* fs: Inode cache scalability V3
@ 2010-10-13 0:15 Dave Chinner
2010-10-13 0:15 ` [PATCH 01/18] kernel: add bl_list Dave Chinner
` (18 more replies)
0 siblings, 19 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
This patch set is derived from Nick Piggin's VFS scalability tree.
there doesn't appear to be any push to get that tree into shape for
.37, so this is an attempt to start the process of finer grained
review of the series for upstream inclusion. I'm hitting VFS lock
contention problems with XFS on 8-16p machines now, so I need to get
this stuff moving.
This patch set is just the basic inode_lock breakup patches plus a
few more simple changes to the inode code. It stops short of
introducing RCU inode freeing because those changes are not
completely baked yet.
As a result, the full inode handling improvements of Nick's patch
set are not realised with this short series. However, my own testing
indicates that the amount of lock traffic and contention is down by
an order of magnitude on an 8-way box for parallel inode create and
unlink workloads, so there is still significant improvements from
just this patch set.
Version 2 of this series is a complete rework of the original patch
series. Nick's original code nested list locks inside the the
inode->i_lock, resulting in a large mess of trylock operations to
get locks out of order all over the place. In many cases, the reason
fo this lock ordering is removed later on in Nick's series as
cleanups are introduced.
As a result I've pulled in several of the cleanups and re-ordered
the series such that cleanups, factoring and list splitting are done
before any of the locking changes. Instead of converting the inode
state flags first, I've converted them last, ensuring that
manipulations are kept inside other locks rather than outside them.
The series is made up of the following steps:
- inode counters are made per-cpu
- inode LRU manipulations are made lazy
- i_list is split into two lists (grows inode by 2
pointers), one for tracking lru status, one for writeback
status
- reference counting is factored, then renamed and locked
differently
- inode hash operations are factored, then locked per bucket
- superblock inode listis locked per-superblock
- inode LRU is locked via a global lock
- unclear what the best way to split this up from
here is, so no attempt is made to optimise
further.
- Currently not showing signs of contention under
any workload on an 8p machine.
- inode IO list are locked via a per-BDI lock
- further analysis needed to determine the next step
in optimising this list. It is extremely contended
under parallel workloads because foreground
throttling (balance_dirty_pages) causes unbound
writeback parallelism and contention. Fixing the
unbound parallelism, I think, is a more important
first optimisation step than making the list
per-cpu.
- lock i_state operations with i_lock
- convert last_ino allocation to a percpu counter
- protect iunique counter with it's own lock
- remove inode_lock
- factor destroying an inode into dispose_one_inode() which
is called from reclaim, dispose_list and iput_final.
None of the patcheѕ are unchanged, and several of them are new or
completely rewritten, so any previous testing is completely
invalidated. I have not tried to optimise locking by using trylock
loops - anywhere that requires out-of-order locking drops locks and
regains the locks needed for the next operation. This approach
simplified the code and lead to several improvments in the patch
series (e.g. moving inode->i_lock inside writeback_single_inode(),
and the dispose_one_inode factoring) that would have gone unnoticed
if I'd gone down the same trylock loop path that Nick used.
I've done some testing so far on ext3, ext4 and XFS (mostly sanity
and lock_stat profile testing), but I have not tested any other
filesystems. IOWs, it is light on testing at this point. I'm sending
out for review now that it passes basic sanity tests so that
comments on the reworked approach can be made.
Version 3:
- whitespace fix in inode_init_early.
- dropped patch that moves inodes around bdi lists as problem is now
fixed in mainline.
- added comments explaining lazy inode LRU manipulations.
- added inode_lru_list_{add,del} helpers much earlier to avoid
needing to export then unexport inode counters.
- renamed i_io to i_wb_list.
- removed iref_locked and just open code internal inode reference
increments.
- added a WARN_ON() condition to detect iref() being called without
a pre-existing reference count.
- added kerneldoc comment to iref().
- dropped iref_read() wrapper function patch
- killed the inode_hash_bucket wrapper, use hlist_bl_head directly
- moved spin_[un]lock_bucket wrappers to list_bl.h, and renamed them
hlist_bl_[un]lock()
- added inode_unhashed() helper function.
- documented use of I_FREEING to ensure removal from inode lru and
writeback lists is kept sane when the inode is being freed.
- added inode_wb_list_del() helper to avoid exporting the
inode_to_bdi() function.
- added comments to explain why we need to set the i_state field
before adding new inodes to various lists
- renamed last_ino_get() to get_next_ino().
- kept invalidate_list/dispose_list pairing for invalidate_inodes(),
but changed the dispose list to use the i_sb_list pointer in the
inode instead of the i_lru to avoid needing to take the
inode_lru_lock for every inode on the superblock list.
- added patch from Christoph Hellwig to spilt up inode_add_to_lists.
Modified the new function names to match the naming convention
used by all the other list helpers in inode.c, and added a
matching inode_sb_list_del() function for symmetry.
- added patch from Christoph Hellwig to move inode number assignment
in get_new_inode() to the callers that don't directly assign an
inode number.
Version 2:
- complete rework of series
--
The following changes since commit cb655d0f3d57c23db51b981648e452988c0223f9:
Linux 2.6.36-rc7 (2010-10-06 13:39:52 -0700)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev.git inode-scale
Christoph Hellwig (2):
fs: split __inode_add_to_list
fs: do not assign default i_ino in new_inode
Dave Chinner (11):
fs: Convert nr_inodes and nr_unused to per-cpu counters
fs: Clean up inode reference counting
exofs: use iput() for inode reference count decrements
fs: rework icount to be a locked variable
fs: Factor inode hash operations into functions
fs: Introduce per-bucket inode hash locks
fs: add a per-superblock lock for the inode list
fs: split locking of inode writeback and LRU lists
fs: Protect inode->i_state with the inode->i_lock
fs: icache remove inode_lock
fs: Reduce inode I_FREEING and factor inode disposal
Eric Dumazet (1):
fs: introduce a per-cpu last_ino allocator
Nick Piggin (4):
kernel: add bl_list
fs: Implement lazy LRU updates for inodes.
fs: inode split IO and LRU lists
fs: Make iunique independent of inode_lock
Documentation/filesystems/Locking | 2 +-
Documentation/filesystems/porting | 10 +-
Documentation/filesystems/vfs.txt | 2 +-
drivers/infiniband/hw/ipath/ipath_fs.c | 1 +
drivers/infiniband/hw/qib/qib_fs.c | 1 +
drivers/misc/ibmasm/ibmasmfs.c | 1 +
drivers/oprofile/oprofilefs.c | 1 +
drivers/usb/core/inode.c | 1 +
drivers/usb/gadget/f_fs.c | 1 +
drivers/usb/gadget/inode.c | 1 +
fs/9p/vfs_inode.c | 5 +-
fs/affs/inode.c | 2 +-
fs/afs/dir.c | 2 +-
fs/anon_inodes.c | 8 +-
fs/autofs4/inode.c | 1 +
fs/bfs/dir.c | 2 +-
fs/binfmt_misc.c | 1 +
fs/block_dev.c | 13 +-
fs/btrfs/inode.c | 18 +-
fs/buffer.c | 2 +-
fs/ceph/mds_client.c | 2 +-
fs/cifs/inode.c | 2 +-
fs/coda/dir.c | 2 +-
fs/configfs/inode.c | 1 +
fs/debugfs/inode.c | 1 +
fs/drop_caches.c | 19 +-
fs/exofs/inode.c | 6 +-
fs/exofs/namei.c | 2 +-
fs/ext2/namei.c | 2 +-
fs/ext3/ialloc.c | 4 +-
fs/ext3/namei.c | 2 +-
fs/ext4/ialloc.c | 4 +-
fs/ext4/mballoc.c | 1 +
fs/ext4/namei.c | 2 +-
fs/freevxfs/vxfs_inode.c | 1 +
fs/fs-writeback.c | 192 +++++---
fs/fuse/control.c | 1 +
fs/gfs2/ops_inode.c | 2 +-
fs/hfs/hfs_fs.h | 2 +-
fs/hfs/inode.c | 2 +-
fs/hfsplus/dir.c | 2 +-
fs/hfsplus/hfsplus_fs.h | 2 +-
fs/hfsplus/inode.c | 2 +-
fs/hpfs/inode.c | 2 +-
fs/hugetlbfs/inode.c | 1 +
fs/inode.c | 785 +++++++++++++++++++++-----------
fs/internal.h | 11 +
fs/jffs2/dir.c | 4 +-
fs/jfs/jfs_txnmgr.c | 2 +-
fs/jfs/namei.c | 2 +-
fs/libfs.c | 2 +-
fs/locks.c | 2 +-
fs/logfs/dir.c | 2 +-
fs/logfs/inode.c | 2 +-
fs/logfs/readwrite.c | 2 +-
fs/minix/namei.c | 2 +-
fs/namei.c | 2 +-
fs/nfs/dir.c | 2 +-
fs/nfs/getroot.c | 2 +-
fs/nfs/inode.c | 4 +-
fs/nfs/nfs4state.c | 2 +-
fs/nfs/write.c | 2 +-
fs/nilfs2/gcdat.c | 1 +
fs/nilfs2/gcinode.c | 22 +-
fs/nilfs2/mdt.c | 5 +-
fs/nilfs2/namei.c | 2 +-
fs/nilfs2/segment.c | 2 +-
fs/nilfs2/the_nilfs.h | 2 +-
fs/notify/inode_mark.c | 47 ++-
fs/notify/mark.c | 1 -
fs/notify/vfsmount_mark.c | 1 -
fs/ntfs/inode.c | 10 +-
fs/ntfs/super.c | 6 +-
fs/ocfs2/dlmfs/dlmfs.c | 2 +
fs/ocfs2/inode.c | 2 +-
fs/ocfs2/namei.c | 2 +-
fs/pipe.c | 2 +
fs/proc/base.c | 2 +
fs/proc/proc_sysctl.c | 2 +
fs/quota/dquot.c | 32 +-
fs/ramfs/inode.c | 1 +
fs/reiserfs/namei.c | 2 +-
fs/reiserfs/stree.c | 2 +-
fs/reiserfs/xattr.c | 2 +-
fs/smbfs/inode.c | 2 +-
fs/super.c | 1 +
fs/sysv/namei.c | 2 +-
fs/ubifs/dir.c | 2 +-
fs/ubifs/super.c | 2 +-
fs/udf/inode.c | 2 +-
fs/udf/namei.c | 2 +-
fs/ufs/namei.c | 2 +-
fs/xfs/linux-2.6/xfs_buf.c | 1 +
fs/xfs/linux-2.6/xfs_iops.c | 6 +-
fs/xfs/linux-2.6/xfs_trace.h | 2 +-
fs/xfs/xfs_inode.h | 3 +-
include/linux/backing-dev.h | 1 +
include/linux/fs.h | 41 ++-
include/linux/list_bl.h | 145 ++++++
include/linux/poison.h | 2 +
include/linux/writeback.h | 4 -
ipc/mqueue.c | 3 +-
kernel/cgroup.c | 1 +
kernel/futex.c | 2 +-
kernel/sysctl.c | 4 +-
mm/backing-dev.c | 28 +-
mm/filemap.c | 6 +-
mm/rmap.c | 6 +-
mm/shmem.c | 7 +-
net/socket.c | 3 +-
net/sunrpc/rpc_pipe.c | 1 +
security/inode.c | 1 +
security/selinux/selinuxfs.c | 1 +
113 files changed, 1059 insertions(+), 538 deletions(-)
create mode 100644 include/linux/list_bl.h
^ permalink raw reply [flat|nested] 50+ messages in thread
* [PATCH 01/18] kernel: add bl_list
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 02/18] fs: Convert nr_inodes and nr_unused to per-cpu counters Dave Chinner
` (17 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Nick Piggin <npiggin@suse.de>
Introduce a type of hlist that can support the use of the lowest bit
in the hlist_head. This will be subsequently used to implement
per-bucket bit spinlock for inode hashes.
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
include/linux/list_bl.h | 127 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/poison.h | 2 +
2 files changed, 129 insertions(+), 0 deletions(-)
create mode 100644 include/linux/list_bl.h
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
new file mode 100644
index 0000000..961bc89
--- /dev/null
+++ b/include/linux/list_bl.h
@@ -0,0 +1,127 @@
+#ifndef _LINUX_LIST_BL_H
+#define _LINUX_LIST_BL_H
+
+#include <linux/list.h>
+#include <linux/bit_spinlock.h>
+
+/*
+ * Special version of lists, where head of the list has a bit spinlock
+ * in the lowest bit. This is useful for scalable hash tables without
+ * increasing memory footprint overhead.
+ *
+ * For modification operations, the 0 bit of hlist_bl_head->first
+ * pointer must be set.
+ */
+
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+#define LIST_BL_LOCKMASK 1UL
+#else
+#define LIST_BL_LOCKMASK 0UL
+#endif
+
+#ifdef CONFIG_DEBUG_LIST
+#define LIST_BL_BUG_ON(x) BUG_ON(x)
+#else
+#define LIST_BL_BUG_ON(x)
+#endif
+
+
+struct hlist_bl_head {
+ struct hlist_bl_node *first;
+};
+
+struct hlist_bl_node {
+ struct hlist_bl_node *next, **pprev;
+};
+#define INIT_HLIST_BL_HEAD(ptr) \
+ ((ptr)->first = NULL)
+
+static inline void init_hlist_bl_node(struct hlist_bl_node *h)
+{
+ h->next = NULL;
+ h->pprev = NULL;
+}
+
+#define hlist_bl_entry(ptr, type, member) container_of(ptr, type, member)
+
+static inline int hlist_bl_unhashed(const struct hlist_bl_node *h)
+{
+ return !h->pprev;
+}
+
+static inline struct hlist_bl_node *hlist_bl_first(struct hlist_bl_head *h)
+{
+ return (struct hlist_bl_node *)
+ ((unsigned long)h->first & ~LIST_BL_LOCKMASK);
+}
+
+static inline void hlist_bl_set_first(struct hlist_bl_head *h,
+ struct hlist_bl_node *n)
+{
+ LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK);
+ LIST_BL_BUG_ON(!bit_spin_is_locked(0, (unsigned long *)&h->first));
+ h->first = (struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK);
+}
+
+static inline int hlist_bl_empty(const struct hlist_bl_head *h)
+{
+ return !((unsigned long)h->first & ~LIST_BL_LOCKMASK);
+}
+
+static inline void hlist_bl_add_head(struct hlist_bl_node *n,
+ struct hlist_bl_head *h)
+{
+ struct hlist_bl_node *first = hlist_bl_first(h);
+
+ n->next = first;
+ if (first)
+ first->pprev = &n->next;
+ n->pprev = &h->first;
+ hlist_bl_set_first(h, n);
+}
+
+static inline void __hlist_bl_del(struct hlist_bl_node *n)
+{
+ struct hlist_bl_node *next = n->next;
+ struct hlist_bl_node **pprev = n->pprev;
+
+ LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK);
+
+ /* pprev may be `first`, so be careful not to lose the lock bit */
+ *pprev = (struct hlist_bl_node *)
+ ((unsigned long)next |
+ ((unsigned long)*pprev & LIST_BL_LOCKMASK));
+ if (next)
+ next->pprev = pprev;
+}
+
+static inline void hlist_bl_del(struct hlist_bl_node *n)
+{
+ __hlist_bl_del(n);
+ n->next = BL_LIST_POISON1;
+ n->pprev = BL_LIST_POISON2;
+}
+
+static inline void hlist_bl_del_init(struct hlist_bl_node *n)
+{
+ if (!hlist_bl_unhashed(n)) {
+ __hlist_bl_del(n);
+ init_hlist_bl_node(n);
+ }
+}
+
+/**
+ * hlist_bl_for_each_entry - iterate over list of given type
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_node to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the hlist_node within the struct.
+ *
+ */
+#define hlist_bl_for_each_entry(tpos, pos, head, member) \
+ for (pos = hlist_bl_first(head); \
+ pos && \
+ ({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1; }); \
+ pos = pos->next)
+
+#endif
diff --git a/include/linux/poison.h b/include/linux/poison.h
index 2110a81..d367d39 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -22,6 +22,8 @@
#define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA)
#define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA)
+#define BL_LIST_POISON1 ((void *) 0x00300300 + POISON_POINTER_DELTA)
+#define BL_LIST_POISON2 ((void *) 0x00400400 + POISON_POINTER_DELTA)
/********** include/linux/timer.h **********/
/*
* Magic number "tsta" to indicate a static timer initializer
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 02/18] fs: Convert nr_inodes and nr_unused to per-cpu counters
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
2010-10-13 0:15 ` [PATCH 01/18] kernel: add bl_list Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 03/18] fs: Implement lazy LRU updates for inodes Dave Chinner
` (16 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
The number of inodes allocated does not need to be tied to the
addition or removal of an inode to/from a list. If we are not tied
to a list lock, we could update the counters when inodes are
initialised or destroyed, but to do that we need to convert the
counters to be per-cpu (i.e. independent of a lock). This means that
we have the freedom to change the list/locking implementation
without needing to care about the counters.
Based on a patch originally from Eric Dumazet.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/fs-writeback.c | 5 +--
fs/inode.c | 64 ++++++++++++++++++++++++++++++++++++---------------
include/linux/fs.h | 4 ++-
kernel/sysctl.c | 4 +-
4 files changed, 52 insertions(+), 25 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ab38fef..58a95b7 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -723,7 +723,7 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb)
wb->last_old_flush = jiffies;
nr_pages = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS) +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused);
+ get_nr_dirty_inodes();
if (nr_pages) {
struct wb_writeback_work work = {
@@ -1090,8 +1090,7 @@ void writeback_inodes_sb(struct super_block *sb)
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- work.nr_pages = nr_dirty + nr_unstable +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused);
+ work.nr_pages = nr_dirty + nr_unstable + get_nr_dirty_inodes();
bdi_queue_work(sb->s_bdi, &work);
wait_for_completion(&done);
diff --git a/fs/inode.c b/fs/inode.c
index 8646433..b3b6a4b 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -103,8 +103,41 @@ static DECLARE_RWSEM(iprune_sem);
*/
struct inodes_stat_t inodes_stat;
+static struct percpu_counter nr_inodes __cacheline_aligned_in_smp;
+static struct percpu_counter nr_inodes_unused __cacheline_aligned_in_smp;
+
static struct kmem_cache *inode_cachep __read_mostly;
+static inline int get_nr_inodes(void)
+{
+ return percpu_counter_sum_positive(&nr_inodes);
+}
+
+static inline int get_nr_inodes_unused(void)
+{
+ return percpu_counter_sum_positive(&nr_inodes_unused);
+}
+
+int get_nr_dirty_inodes(void)
+{
+ int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
+ return nr_dirty > 0 ? nr_dirty : 0;
+
+}
+
+/*
+ * Handle nr_inode sysctl
+ */
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
+int proc_nr_inodes(ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ inodes_stat.nr_inodes = get_nr_inodes();
+ inodes_stat.nr_unused = get_nr_inodes_unused();
+ return proc_dointvec(table, write, buffer, lenp, ppos);
+}
+#endif
+
static void wake_up_inode(struct inode *inode)
{
/*
@@ -192,6 +225,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_fsnotify_mask = 0;
#endif
+ percpu_counter_inc(&nr_inodes);
+
return 0;
out:
return -ENOMEM;
@@ -232,6 +267,7 @@ void __destroy_inode(struct inode *inode)
if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
posix_acl_release(inode->i_default_acl);
#endif
+ percpu_counter_dec(&nr_inodes);
}
EXPORT_SYMBOL(__destroy_inode);
@@ -286,7 +322,7 @@ void __iget(struct inode *inode)
if (!(inode->i_state & (I_DIRTY|I_SYNC)))
list_move(&inode->i_list, &inode_in_use);
- inodes_stat.nr_unused--;
+ percpu_counter_dec(&nr_inodes_unused);
}
void end_writeback(struct inode *inode)
@@ -327,8 +363,6 @@ static void evict(struct inode *inode)
*/
static void dispose_list(struct list_head *head)
{
- int nr_disposed = 0;
-
while (!list_empty(head)) {
struct inode *inode;
@@ -344,11 +378,7 @@ static void dispose_list(struct list_head *head)
wake_up_inode(inode);
destroy_inode(inode);
- nr_disposed++;
}
- spin_lock(&inode_lock);
- inodes_stat.nr_inodes -= nr_disposed;
- spin_unlock(&inode_lock);
}
/*
@@ -357,7 +387,7 @@ static void dispose_list(struct list_head *head)
static int invalidate_list(struct list_head *head, struct list_head *dispose)
{
struct list_head *next;
- int busy = 0, count = 0;
+ int busy = 0;
next = head->next;
for (;;) {
@@ -383,13 +413,11 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
list_move(&inode->i_list, dispose);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
- count++;
+ percpu_counter_dec(&nr_inodes_unused);
continue;
}
busy = 1;
}
- /* only unused inodes may be cached with i_count zero */
- inodes_stat.nr_unused -= count;
return busy;
}
@@ -448,7 +476,6 @@ static int can_unuse(struct inode *inode)
static void prune_icache(int nr_to_scan)
{
LIST_HEAD(freeable);
- int nr_pruned = 0;
int nr_scanned;
unsigned long reap = 0;
@@ -484,9 +511,8 @@ static void prune_icache(int nr_to_scan)
list_move(&inode->i_list, &freeable);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
- nr_pruned++;
+ percpu_counter_dec(&nr_inodes_unused);
}
- inodes_stat.nr_unused -= nr_pruned;
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
@@ -518,7 +544,7 @@ static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
return -1;
prune_icache(nr);
}
- return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
+ return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker icache_shrinker = {
@@ -595,7 +621,6 @@ static inline void
__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
struct inode *inode)
{
- inodes_stat.nr_inodes++;
list_add(&inode->i_list, &inode_in_use);
list_add(&inode->i_sb_list, &sb->s_inodes);
if (head)
@@ -1215,7 +1240,7 @@ static void iput_final(struct inode *inode)
if (!drop) {
if (!(inode->i_state & (I_DIRTY|I_SYNC)))
list_move(&inode->i_list, &inode_unused);
- inodes_stat.nr_unused++;
+ percpu_counter_inc(&nr_inodes_unused);
if (sb->s_flags & MS_ACTIVE) {
spin_unlock(&inode_lock);
return;
@@ -1227,14 +1252,13 @@ static void iput_final(struct inode *inode)
spin_lock(&inode_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- inodes_stat.nr_unused--;
+ percpu_counter_dec(&nr_inodes_unused);
hlist_del_init(&inode->i_hash);
}
list_del_init(&inode->i_list);
list_del_init(&inode->i_sb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
- inodes_stat.nr_inodes--;
spin_unlock(&inode_lock);
evict(inode);
spin_lock(&inode_lock);
@@ -1503,6 +1527,8 @@ void __init inode_init(void)
SLAB_MEM_SPREAD),
init_once);
register_shrinker(&icache_shrinker);
+ percpu_counter_init(&nr_inodes, 0);
+ percpu_counter_init(&nr_inodes_unused, 0);
/* Hash may have been set up in inode_init_early */
if (!hashdist)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 63d069b..1fb92f9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -407,6 +407,7 @@ extern struct files_stat_struct files_stat;
extern int get_max_files(void);
extern int sysctl_nr_open;
extern struct inodes_stat_t inodes_stat;
+extern int get_nr_dirty_inodes(void);
extern int leases_enable, lease_break_time;
struct buffer_head;
@@ -2474,7 +2475,8 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
struct ctl_table;
int proc_nr_files(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
-
+int proc_nr_inodes(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
int __init get_filesystem_list(char *buf);
#define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f88552c..33d1733 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1340,14 +1340,14 @@ static struct ctl_table fs_table[] = {
.data = &inodes_stat,
.maxlen = 2*sizeof(int),
.mode = 0444,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_nr_inodes,
},
{
.procname = "inode-state",
.data = &inodes_stat,
.maxlen = 7*sizeof(int),
.mode = 0444,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_nr_inodes,
},
{
.procname = "file-nr",
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 03/18] fs: Implement lazy LRU updates for inodes.
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
2010-10-13 0:15 ` [PATCH 01/18] kernel: add bl_list Dave Chinner
2010-10-13 0:15 ` [PATCH 02/18] fs: Convert nr_inodes and nr_unused to per-cpu counters Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 13:32 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 04/18] fs: inode split IO and LRU lists Dave Chinner
` (15 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Nick Piggin <npiggin@suse.de>
Convert the inode LRU to use lazy updates to reduce lock and
cacheline traffic. We avoid moving inodes around in the LRU list
during iget/iput operations so these frequent operations don't need
to access the LRUs. Instead, we defer the refcount checks to
reclaim-time and use a per-inode state flag, I_REFERENCED, to tell
reclaim that iget has touched the inode in the past. This means that
only reclaim should be touching the LRU with any frequency, hence
significantly reducing lock acquisitions and the amount contention
on LRU updates.
This also removes the inode_in_use list, which means we now only
have one list for tracking the inode LRU status. This makes it much
simpler to split out the LRU list operations under it's own lock.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/fs-writeback.c | 12 +----
fs/inode.c | 92 +++++++++++++++++++++++++++++++--------------
fs/internal.h | 6 +++
include/linux/fs.h | 13 +++---
include/linux/writeback.h | 1 -
5 files changed, 80 insertions(+), 44 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 58a95b7..61c11d5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -408,16 +408,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completion.
*/
redirty_tail(inode);
- } else if (atomic_read(&inode->i_count)) {
- /*
- * The inode is clean, inuse
- */
- list_move(&inode->i_list, &inode_in_use);
} else {
- /*
- * The inode is clean, unused
- */
- list_move(&inode->i_list, &inode_unused);
+ /* The inode is clean */
+ list_del_init(&inode->i_list);
+ inode_lru_list_add(inode);
}
}
inode_sync_complete(inode);
diff --git a/fs/inode.c b/fs/inode.c
index b3b6a4b..5dd74b4 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -72,7 +72,6 @@ static unsigned int i_hash_shift __read_mostly;
* allowing for low-overhead inode sync() operations.
*/
-LIST_HEAD(inode_in_use);
LIST_HEAD(inode_unused);
static struct hlist_head *inode_hashtable __read_mostly;
@@ -291,6 +290,7 @@ void inode_init_once(struct inode *inode)
INIT_HLIST_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_devices);
+ INIT_LIST_HEAD(&inode->i_list);
INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
spin_lock_init(&inode->i_data.tree_lock);
spin_lock_init(&inode->i_data.i_mmap_lock);
@@ -317,12 +317,21 @@ static void init_once(void *foo)
*/
void __iget(struct inode *inode)
{
- if (atomic_inc_return(&inode->i_count) != 1)
- return;
+ atomic_inc(&inode->i_count);
+}
- if (!(inode->i_state & (I_DIRTY|I_SYNC)))
- list_move(&inode->i_list, &inode_in_use);
- percpu_counter_dec(&nr_inodes_unused);
+void inode_lru_list_add(struct inode *inode)
+{
+ list_add(&inode->i_list, &inode_unused);
+ percpu_counter_inc(&nr_inodes_unused);
+}
+
+void inode_lru_list_del(struct inode *inode)
+{
+ if (!list_empty(&inode->i_list)) {
+ list_del_init(&inode->i_list);
+ percpu_counter_dec(&nr_inodes_unused);
+ }
}
void end_writeback(struct inode *inode)
@@ -367,7 +376,7 @@ static void dispose_list(struct list_head *head)
struct inode *inode;
inode = list_first_entry(head, struct inode, i_list);
- list_del(&inode->i_list);
+ list_del_init(&inode->i_list);
evict(inode);
@@ -410,9 +419,9 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
continue;
invalidate_inode_buffers(inode);
if (!atomic_read(&inode->i_count)) {
- list_move(&inode->i_list, dispose);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ list_move(&inode->i_list, dispose);
percpu_counter_dec(&nr_inodes_unused);
continue;
}
@@ -461,17 +470,20 @@ static int can_unuse(struct inode *inode)
}
/*
- * Scan `goal' inodes on the unused list for freeable ones. They are moved to
- * a temporary list and then are freed outside inode_lock by dispose_list().
+ * Scan `goal' inodes on the unused list for freeable ones. They are moved to a
+ * temporary list and then are freed outside inode_lock by dispose_list().
*
* Any inodes which are pinned purely because of attached pagecache have their
- * pagecache removed. We expect the final iput() on that inode to add it to
- * the front of the inode_unused list. So look for it there and if the
- * inode is still freeable, proceed. The right inode is found 99.9% of the
- * time in testing on a 4-way.
+ * pagecache removed. If the inode has metadata buffers attached to
+ * mapping->private_list then try to remove them.
*
- * If the inode has metadata buffers attached to mapping->private_list then
- * try to remove them.
+ * If the inode has the I_REFERENCED flag set, it means that it has been used
+ * recently - the flag is set in iput_final(). When we encounter such an inode,
+ * clear the flag and move it to the back of the LRU so it gets another pass
+ * through the LRU before it gets reclaimed. This is necessary because of the
+ * fact we are doing lazy LRU updates to minimise lock contention so the LRU
+ * does not have strict ordering. Hence we don't want to reclaim inodes with
+ * this flag set because they are the inodes that are out of order...
*/
static void prune_icache(int nr_to_scan)
{
@@ -489,8 +501,21 @@ static void prune_icache(int nr_to_scan)
inode = list_entry(inode_unused.prev, struct inode, i_list);
- if (inode->i_state || atomic_read(&inode->i_count)) {
+ /*
+ * Referenced or dirty inodes are still in use. Give them
+ * another pass through the LRU as we canot reclaim them now.
+ */
+ if (atomic_read(&inode->i_count) ||
+ (inode->i_state & ~I_REFERENCED)) {
+ list_del_init(&inode->i_list);
+ percpu_counter_dec(&nr_inodes_unused);
+ continue;
+ }
+
+ /* recently referenced inodes get one more pass */
+ if (inode->i_state & I_REFERENCED) {
list_move(&inode->i_list, &inode_unused);
+ inode->i_state &= ~I_REFERENCED;
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
@@ -502,11 +527,15 @@ static void prune_icache(int nr_to_scan)
iput(inode);
spin_lock(&inode_lock);
- if (inode != list_entry(inode_unused.next,
- struct inode, i_list))
- continue; /* wrong inode or list_empty */
- if (!can_unuse(inode))
+ /*
+ * if we can't reclaim this inode immediately, give it
+ * another pass through the free list so we don't spin
+ * on it.
+ */
+ if (!can_unuse(inode)) {
+ list_move(&inode->i_list, &inode_unused);
continue;
+ }
}
list_move(&inode->i_list, &freeable);
WARN_ON(inode->i_state & I_NEW);
@@ -621,7 +650,6 @@ static inline void
__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
struct inode *inode)
{
- list_add(&inode->i_list, &inode_in_use);
list_add(&inode->i_sb_list, &sb->s_inodes);
if (head)
hlist_add_head(&inode->i_hash, head);
@@ -1238,10 +1266,12 @@ static void iput_final(struct inode *inode)
drop = generic_drop_inode(inode);
if (!drop) {
- if (!(inode->i_state & (I_DIRTY|I_SYNC)))
- list_move(&inode->i_list, &inode_unused);
- percpu_counter_inc(&nr_inodes_unused);
if (sb->s_flags & MS_ACTIVE) {
+ inode->i_state |= I_REFERENCED;
+ if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
+ list_del_init(&inode->i_list);
+ inode_lru_list_add(inode);
+ }
spin_unlock(&inode_lock);
return;
}
@@ -1252,13 +1282,19 @@ static void iput_final(struct inode *inode)
spin_lock(&inode_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- percpu_counter_dec(&nr_inodes_unused);
hlist_del_init(&inode->i_hash);
}
- list_del_init(&inode->i_list);
- list_del_init(&inode->i_sb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+
+ /*
+ * After we delete the inode from the LRU here, we avoid moving dirty
+ * inodes back onto the LRU now because I_FREEING is set and hence
+ * writeback_single_inode() won't move the inode around.
+ */
+ inode_lru_list_del(inode);
+
+ list_del_init(&inode->i_sb_list);
spin_unlock(&inode_lock);
evict(inode);
spin_lock(&inode_lock);
diff --git a/fs/internal.h b/fs/internal.h
index a6910e9..ece3565 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -101,3 +101,9 @@ extern void put_super(struct super_block *sb);
struct nameidata;
extern struct file *nameidata_to_filp(struct nameidata *);
extern void release_open_intent(struct nameidata *);
+
+/*
+ * inode.c
+ */
+extern void inode_lru_list_add(struct inode *inode);
+extern void inode_lru_list_del(struct inode *inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1fb92f9..af1d516 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1632,16 +1632,17 @@ struct super_operations {
*
* Q: What is the difference between I_WILL_FREE and I_FREEING?
*/
-#define I_DIRTY_SYNC 1
-#define I_DIRTY_DATASYNC 2
-#define I_DIRTY_PAGES 4
+#define I_DIRTY_SYNC 0x01
+#define I_DIRTY_DATASYNC 0x02
+#define I_DIRTY_PAGES 0x04
#define __I_NEW 3
#define I_NEW (1 << __I_NEW)
-#define I_WILL_FREE 16
-#define I_FREEING 32
-#define I_CLEAR 64
+#define I_WILL_FREE 0x10
+#define I_FREEING 0x20
+#define I_CLEAR 0x40
#define __I_SYNC 7
#define I_SYNC (1 << __I_SYNC)
+#define I_REFERENCED 0x100
#define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 72a5d64..f956b66 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -10,7 +10,6 @@
struct backing_dev_info;
extern spinlock_t inode_lock;
-extern struct list_head inode_in_use;
extern struct list_head inode_unused;
/*
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 04/18] fs: inode split IO and LRU lists
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (2 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 03/18] fs: Implement lazy LRU updates for inodes Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 11:31 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 05/18] fs: Clean up inode reference counting Dave Chinner
` (14 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Nick Piggin <npiggin@suse.de>
The use of the same inode list structure (inode->i_list) for two
different list constructs with different lifecycles and purposes
makes it impossible to separate the locking of the different
operations. Therefore, to enable the separation of the locking of
the writeback and reclaim lists, split the inode->i_list into two
separate lists dedicated to their specific tracking functions.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/fs-writeback.c | 27 ++++++++++++++-------------
fs/inode.c | 40 ++++++++++++++++++++++------------------
fs/nilfs2/mdt.c | 3 ++-
include/linux/fs.h | 3 ++-
include/linux/writeback.h | 1 -
mm/backing-dev.c | 6 +++---
6 files changed, 43 insertions(+), 37 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 61c11d5..99f84a6 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -172,11 +172,11 @@ static void redirty_tail(struct inode *inode)
if (!list_empty(&wb->b_dirty)) {
struct inode *tail;
- tail = list_entry(wb->b_dirty.next, struct inode, i_list);
+ tail = list_entry(wb->b_dirty.next, struct inode, i_wb_list);
if (time_before(inode->dirtied_when, tail->dirtied_when))
inode->dirtied_when = jiffies;
}
- list_move(&inode->i_list, &wb->b_dirty);
+ list_move(&inode->i_wb_list, &wb->b_dirty);
}
/*
@@ -186,7 +186,7 @@ static void requeue_io(struct inode *inode)
{
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
- list_move(&inode->i_list, &wb->b_more_io);
+ list_move(&inode->i_wb_list, &wb->b_more_io);
}
static void inode_sync_complete(struct inode *inode)
@@ -227,14 +227,15 @@ static void move_expired_inodes(struct list_head *delaying_queue,
int do_sb_sort = 0;
while (!list_empty(delaying_queue)) {
- inode = list_entry(delaying_queue->prev, struct inode, i_list);
+ inode = list_entry(delaying_queue->prev,
+ struct inode, i_wb_list);
if (older_than_this &&
inode_dirtied_after(inode, *older_than_this))
break;
if (sb && sb != inode->i_sb)
do_sb_sort = 1;
sb = inode->i_sb;
- list_move(&inode->i_list, &tmp);
+ list_move(&inode->i_wb_list, &tmp);
}
/* just one sb in list, splice to dispatch_queue and we're done */
@@ -245,12 +246,12 @@ static void move_expired_inodes(struct list_head *delaying_queue,
/* Move inodes from one superblock together */
while (!list_empty(&tmp)) {
- inode = list_entry(tmp.prev, struct inode, i_list);
+ inode = list_entry(tmp.prev, struct inode, i_wb_list);
sb = inode->i_sb;
list_for_each_prev_safe(pos, node, &tmp) {
- inode = list_entry(pos, struct inode, i_list);
+ inode = list_entry(pos, struct inode, i_wb_list);
if (inode->i_sb == sb)
- list_move(&inode->i_list, dispatch_queue);
+ list_move(&inode->i_wb_list, dispatch_queue);
}
}
}
@@ -410,7 +411,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
redirty_tail(inode);
} else {
/* The inode is clean */
- list_del_init(&inode->i_list);
+ list_del_init(&inode->i_wb_list);
inode_lru_list_add(inode);
}
}
@@ -460,7 +461,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
while (!list_empty(&wb->b_io)) {
long pages_skipped;
struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode, i_wb_list);
if (inode->i_sb != sb) {
if (only_this_sb) {
@@ -531,7 +532,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
while (!list_empty(&wb->b_io)) {
struct inode *inode = list_entry(wb->b_io.prev,
- struct inode, i_list);
+ struct inode, i_wb_list);
struct super_block *sb = inode->i_sb;
if (!pin_sb_for_writeback(sb)) {
@@ -670,7 +671,7 @@ static long wb_writeback(struct bdi_writeback *wb,
spin_lock(&inode_lock);
if (!list_empty(&wb->b_more_io)) {
inode = list_entry(wb->b_more_io.prev,
- struct inode, i_list);
+ struct inode, i_wb_list);
trace_wbc_writeback_wait(&wbc, wb->bdi);
inode_wait_for_writeback(inode);
}
@@ -984,7 +985,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
}
inode->dirtied_when = jiffies;
- list_move(&inode->i_list, &bdi->wb.b_dirty);
+ list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
}
}
out:
diff --git a/fs/inode.c b/fs/inode.c
index 5dd74b4..fd65368 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -72,7 +72,7 @@ static unsigned int i_hash_shift __read_mostly;
* allowing for low-overhead inode sync() operations.
*/
-LIST_HEAD(inode_unused);
+static LIST_HEAD(inode_lru);
static struct hlist_head *inode_hashtable __read_mostly;
/*
@@ -272,6 +272,7 @@ EXPORT_SYMBOL(__destroy_inode);
void destroy_inode(struct inode *inode)
{
+ BUG_ON(!list_empty(&inode->i_lru));
__destroy_inode(inode);
if (inode->i_sb->s_op->destroy_inode)
inode->i_sb->s_op->destroy_inode(inode);
@@ -290,7 +291,8 @@ void inode_init_once(struct inode *inode)
INIT_HLIST_NODE(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_devices);
- INIT_LIST_HEAD(&inode->i_list);
+ INIT_LIST_HEAD(&inode->i_wb_list);
+ INIT_LIST_HEAD(&inode->i_lru);
INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
spin_lock_init(&inode->i_data.tree_lock);
spin_lock_init(&inode->i_data.i_mmap_lock);
@@ -322,14 +324,16 @@ void __iget(struct inode *inode)
void inode_lru_list_add(struct inode *inode)
{
- list_add(&inode->i_list, &inode_unused);
- percpu_counter_inc(&nr_inodes_unused);
+ if (list_empty(&inode->i_lru)) {
+ list_add(&inode->i_lru, &inode_lru);
+ percpu_counter_inc(&nr_inodes_unused);
+ }
}
void inode_lru_list_del(struct inode *inode)
{
- if (!list_empty(&inode->i_list)) {
- list_del_init(&inode->i_list);
+ if (!list_empty(&inode->i_lru)) {
+ list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
}
}
@@ -375,8 +379,8 @@ static void dispose_list(struct list_head *head)
while (!list_empty(head)) {
struct inode *inode;
- inode = list_first_entry(head, struct inode, i_list);
- list_del_init(&inode->i_list);
+ inode = list_first_entry(head, struct inode, i_lru);
+ list_del_init(&inode->i_lru);
evict(inode);
@@ -421,7 +425,7 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
if (!atomic_read(&inode->i_count)) {
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
- list_move(&inode->i_list, dispose);
+ list_move(&inode->i_lru, dispose);
percpu_counter_dec(&nr_inodes_unused);
continue;
}
@@ -496,10 +500,10 @@ static void prune_icache(int nr_to_scan)
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;
- if (list_empty(&inode_unused))
+ if (list_empty(&inode_lru))
break;
- inode = list_entry(inode_unused.prev, struct inode, i_list);
+ inode = list_entry(inode_lru.prev, struct inode, i_lru);
/*
* Referenced or dirty inodes are still in use. Give them
@@ -507,14 +511,14 @@ static void prune_icache(int nr_to_scan)
*/
if (atomic_read(&inode->i_count) ||
(inode->i_state & ~I_REFERENCED)) {
- list_del_init(&inode->i_list);
+ list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
continue;
}
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
- list_move(&inode->i_list, &inode_unused);
+ list_move(&inode->i_lru, &inode_lru);
inode->i_state &= ~I_REFERENCED;
continue;
}
@@ -533,11 +537,12 @@ static void prune_icache(int nr_to_scan)
* on it.
*/
if (!can_unuse(inode)) {
- list_move(&inode->i_list, &inode_unused);
+ list_move(&inode->i_lru, &inode_lru);
continue;
}
}
- list_move(&inode->i_list, &freeable);
+ list_move(&inode->i_lru, &freeable);
+ list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
percpu_counter_dec(&nr_inodes_unused);
@@ -1268,10 +1273,8 @@ static void iput_final(struct inode *inode)
if (!drop) {
if (sb->s_flags & MS_ACTIVE) {
inode->i_state |= I_REFERENCED;
- if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
- list_del_init(&inode->i_list);
+ if (!(inode->i_state & (I_DIRTY|I_SYNC)))
inode_lru_list_add(inode);
- }
spin_unlock(&inode_lock);
return;
}
@@ -1284,6 +1287,7 @@ static void iput_final(struct inode *inode)
inode->i_state &= ~I_WILL_FREE;
hlist_del_init(&inode->i_hash);
}
+ list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index d01aff4..62756b4 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -504,7 +504,8 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
#endif
inode->dirtied_when = 0;
- INIT_LIST_HEAD(&inode->i_list);
+ INIT_LIST_HEAD(&inode->i_wb_list);
+ INIT_LIST_HEAD(&inode->i_lru);
INIT_LIST_HEAD(&inode->i_sb_list);
inode->i_state = 0;
#endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index af1d516..90d2b47 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -725,7 +725,8 @@ struct posix_acl;
struct inode {
struct hlist_node i_hash;
- struct list_head i_list; /* backing dev IO list */
+ struct list_head i_wb_list; /* backing dev IO list */
+ struct list_head i_lru; /* inode LRU list */
struct list_head i_sb_list;
struct list_head i_dentry;
unsigned long i_ino;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index f956b66..242b6f8 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -10,7 +10,6 @@
struct backing_dev_info;
extern spinlock_t inode_lock;
-extern struct list_head inode_unused;
/*
* fs/fs-writeback.c
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 65d4204..15d5097 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -74,11 +74,11 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
nr_wb = nr_dirty = nr_io = nr_more_io = 0;
spin_lock(&inode_lock);
- list_for_each_entry(inode, &wb->b_dirty, i_list)
+ list_for_each_entry(inode, &wb->b_dirty, i_wb_list)
nr_dirty++;
- list_for_each_entry(inode, &wb->b_io, i_list)
+ list_for_each_entry(inode, &wb->b_io, i_wb_list)
nr_io++;
- list_for_each_entry(inode, &wb->b_more_io, i_list)
+ list_for_each_entry(inode, &wb->b_more_io, i_wb_list)
nr_more_io++;
spin_unlock(&inode_lock);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 05/18] fs: Clean up inode reference counting
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (3 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 04/18] fs: inode split IO and LRU lists Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 11:33 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 06/18] exofs: use iput() for inode reference count decrements Dave Chinner
` (13 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
Lots of filesystem code open codes the act of getting a reference to
an inode. Factor the open coded inode lock, increment, unlock into
a function iref(). This removes most direct external references to
the inode reference count.
Originally based on a patch from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/9p/vfs_inode.c | 5 +++--
fs/affs/inode.c | 2 +-
fs/afs/dir.c | 2 +-
fs/anon_inodes.c | 7 +------
fs/bfs/dir.c | 2 +-
fs/block_dev.c | 13 ++++++-------
fs/btrfs/inode.c | 2 +-
fs/coda/dir.c | 2 +-
fs/drop_caches.c | 2 +-
fs/exofs/inode.c | 2 +-
fs/exofs/namei.c | 2 +-
fs/ext2/namei.c | 2 +-
fs/ext3/namei.c | 2 +-
fs/ext4/namei.c | 2 +-
fs/fs-writeback.c | 7 +++----
fs/gfs2/ops_inode.c | 2 +-
fs/hfsplus/dir.c | 2 +-
fs/inode.c | 34 ++++++++++++++++++++++------------
fs/jffs2/dir.c | 4 ++--
fs/jfs/jfs_txnmgr.c | 2 +-
fs/jfs/namei.c | 2 +-
fs/libfs.c | 2 +-
fs/logfs/dir.c | 2 +-
fs/minix/namei.c | 2 +-
fs/namei.c | 2 +-
fs/nfs/dir.c | 2 +-
fs/nfs/getroot.c | 2 +-
fs/nfs/write.c | 2 +-
fs/nilfs2/namei.c | 2 +-
fs/notify/inode_mark.c | 8 ++++----
fs/ntfs/super.c | 4 ++--
fs/ocfs2/namei.c | 2 +-
fs/quota/dquot.c | 2 +-
fs/reiserfs/namei.c | 2 +-
fs/sysv/namei.c | 2 +-
fs/ubifs/dir.c | 2 +-
fs/udf/namei.c | 2 +-
fs/ufs/namei.c | 2 +-
fs/xfs/linux-2.6/xfs_iops.c | 2 +-
fs/xfs/xfs_inode.h | 2 +-
include/linux/fs.h | 2 +-
ipc/mqueue.c | 2 +-
kernel/futex.c | 2 +-
mm/shmem.c | 2 +-
net/socket.c | 2 +-
45 files changed, 80 insertions(+), 76 deletions(-)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 9e670d5..1f76624 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1789,9 +1789,10 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
kfree(st);
} else {
/* Caching disabled. No need to get upto date stat info.
- * This dentry will be released immediately. So, just i_count++
+ * This dentry will be released immediately. So, just take
+ * a reference.
*/
- atomic_inc(&old_dentry->d_inode->i_count);
+ iref(old_dentry->d_inode);
}
dentry->d_op = old_dentry->d_op;
diff --git a/fs/affs/inode.c b/fs/affs/inode.c
index 3a0fdec..2100852 100644
--- a/fs/affs/inode.c
+++ b/fs/affs/inode.c
@@ -388,7 +388,7 @@ affs_add_entry(struct inode *dir, struct inode *inode, struct dentry *dentry, s3
affs_adjust_checksum(inode_bh, block - be32_to_cpu(chain));
mark_buffer_dirty_inode(inode_bh, inode);
inode->i_nlink = 2;
- atomic_inc(&inode->i_count);
+ iref(inode);
}
affs_fix_checksum(sb, bh);
mark_buffer_dirty_inode(bh, inode);
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 0d38c09..87d8c03 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1045,7 +1045,7 @@ static int afs_link(struct dentry *from, struct inode *dir,
if (ret < 0)
goto link_error;
- atomic_inc(&vnode->vfs_inode.i_count);
+ iref(&vnode->vfs_inode);
d_instantiate(dentry, &vnode->vfs_inode);
key_put(key);
_leave(" = 0");
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index e4b75d6..451be78 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -109,12 +109,7 @@ struct file *anon_inode_getfile(const char *name,
goto err_module;
path.mnt = mntget(anon_inode_mnt);
- /*
- * We know the anon_inode inode count is always greater than zero,
- * so we can avoid doing an igrab() and we can use an open-coded
- * atomic_inc().
- */
- atomic_inc(&anon_inode_inode->i_count);
+ iref(anon_inode_inode);
path.dentry->d_op = &anon_inodefs_dentry_operations;
d_instantiate(path.dentry, anon_inode_inode);
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
index d967e05..6e93a37 100644
--- a/fs/bfs/dir.c
+++ b/fs/bfs/dir.c
@@ -176,7 +176,7 @@ static int bfs_link(struct dentry *old, struct inode *dir,
inc_nlink(inode);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(new, inode);
mutex_unlock(&info->bfs_lock);
return 0;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 50e8c85..d17f02f 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -550,7 +550,7 @@ EXPORT_SYMBOL(bdget);
*/
struct block_device *bdgrab(struct block_device *bdev)
{
- atomic_inc(&bdev->bd_inode->i_count);
+ iref(bdev->bd_inode);
return bdev;
}
@@ -580,7 +580,7 @@ static struct block_device *bd_acquire(struct inode *inode)
spin_lock(&bdev_lock);
bdev = inode->i_bdev;
if (bdev) {
- atomic_inc(&bdev->bd_inode->i_count);
+ bdgrab(bdev);
spin_unlock(&bdev_lock);
return bdev;
}
@@ -591,12 +591,11 @@ static struct block_device *bd_acquire(struct inode *inode)
spin_lock(&bdev_lock);
if (!inode->i_bdev) {
/*
- * We take an additional bd_inode->i_count for inode,
- * and it's released in clear_inode() of inode.
- * So, we can access it via ->i_mapping always
- * without igrab().
+ * We take an additional bdev reference here so
+ * we can access it via ->i_mapping always
+ * without first needing to grab a reference.
*/
- atomic_inc(&bdev->bd_inode->i_count);
+ bdgrab(bdev);
inode->i_bdev = bdev;
inode->i_mapping = bdev->bd_inode->i_mapping;
list_add(&inode->i_devices, &bdev->bd_inodes);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c038644..80e28bf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4758,7 +4758,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
}
btrfs_set_trans_block_group(trans, dir);
- atomic_inc(&inode->i_count);
+ iref(inode);
err = btrfs_add_nondir(trans, dentry, inode, 1, index);
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index ccd98b0..ac8b913 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -303,7 +303,7 @@ static int coda_link(struct dentry *source_de, struct inode *dir_inode,
}
coda_dir_update_mtime(dir_inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(de, inode);
inc_nlink(inode);
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 2195c21..c2721fa 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -22,7 +22,7 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
continue;
if (inode->i_mapping->nrpages == 0)
continue;
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index eb7368e..b631ff3 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1154,7 +1154,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
/* increment the refcount so that the inode will still be around when we
* reach the callback
*/
- atomic_inc(&inode->i_count);
+ iref(inode);
ios->done = create_done;
ios->private = inode;
diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
index b7dd0c2..f2a30a0 100644
--- a/fs/exofs/namei.c
+++ b/fs/exofs/namei.c
@@ -153,7 +153,7 @@ static int exofs_link(struct dentry *old_dentry, struct inode *dir,
inode->i_ctime = CURRENT_TIME;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
return exofs_add_nondir(dentry, inode);
}
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 71efb0e..b15435f 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -206,7 +206,7 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
err = ext2_add_link(dentry, inode);
if (!err) {
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 2b35ddb..6c7a5d6 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -2260,7 +2260,7 @@ retry:
inode->i_ctime = CURRENT_TIME_SEC;
inc_nlink(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
err = ext3_add_entry(handle, dentry, inode);
if (!err) {
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 314c0d3..a406a85 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2312,7 +2312,7 @@ retry:
inode->i_ctime = ext4_current_time(inode);
ext4_inc_count(handle, inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
err = ext4_add_entry(handle, dentry, inode);
if (!err) {
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 99f84a6..8fb092a 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -298,8 +298,7 @@ static void inode_wait_for_writeback(struct inode *inode)
/*
* Write out an inode's dirty pages. Called under inode_lock. Either the
- * caller has ref on the inode (either via __iget or via syscall against an fd)
- * or the inode has I_WILL_FREE set (via generic_forget_inode)
+ * caller has a reference on the inode or the inode has I_WILL_FREE set.
*
* If `wait' is set, wait on the writeout.
*
@@ -494,7 +493,7 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
return 1;
BUG_ON(inode->i_state & I_FREEING);
- __iget(inode);
+ atomic_inc(&inode->i_count);
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
@@ -1040,7 +1039,7 @@ static void wait_sb_inodes(struct super_block *sb)
mapping = inode->i_mapping;
if (mapping->nrpages == 0)
continue;
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index 1009be2..508407d 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -253,7 +253,7 @@ out_parent:
gfs2_holder_uninit(ghs);
gfs2_holder_uninit(ghs + 1);
if (!error) {
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(dentry, inode);
mark_inode_dirty(inode);
}
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 764fd1b..e2ce54d 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -301,7 +301,7 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
inc_nlink(inode);
hfsplus_instantiate(dst_dentry, inode, cnid);
- atomic_inc(&inode->i_count);
+ iref(inode);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
HFSPLUS_SB(sb).file_count++;
diff --git a/fs/inode.c b/fs/inode.c
index fd65368..ee242c1 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -314,13 +314,23 @@ static void init_once(void *foo)
inode_init_once(inode);
}
-/*
- * inode_lock must be held
+/**
+ * iref - increment the reference count on an inode
+ * @inode: inode to take a reference on
+ *
+ * iref() should be called to take an extra reference to an inode. The inode
+ * must already have a reference count obtained via igrab() as iref() does not
+ * do checks for the inode being freed and hence cannot be used to initially
+ * obtain a reference to the inode.
*/
-void __iget(struct inode *inode)
+void iref(struct inode *inode)
{
+ WARN_ON(atomic_read(&inode->i_count < 1));
+ spin_lock(&inode_lock);
atomic_inc(&inode->i_count);
+ spin_unlock(&inode_lock);
}
+EXPORT_SYMBOL_GPL(iref);
void inode_lru_list_add(struct inode *inode)
{
@@ -523,7 +533,7 @@ static void prune_icache(int nr_to_scan)
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
@@ -589,7 +599,7 @@ static struct shrinker icache_shrinker = {
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
- * NOTE: we are not increasing the inode-refcount, you must call __iget()
+ * NOTE: we are not increasing the inode-refcount, you must take a reference
* by hand after calling find_inode now! This simplifies iunique and won't
* add any additional branch in the common code.
*/
@@ -793,7 +803,7 @@ static struct inode *get_new_inode(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- __iget(old);
+ atomic_inc(&old->i_count);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -840,7 +850,7 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- __iget(old);
+ atomic_inc(&old->i_count);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -893,7 +903,7 @@ struct inode *igrab(struct inode *inode)
{
spin_lock(&inode_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
- __iget(inode);
+ atomic_inc(&inode->i_count);
else
/*
* Handle the case where s_op->clear_inode is not been
@@ -934,7 +944,7 @@ static struct inode *ifind(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode(sb, head, test, data);
if (inode) {
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
if (likely(wait))
wait_on_inode(inode);
@@ -967,7 +977,7 @@ static struct inode *ifind_fast(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode_fast(sb, head, ino);
if (inode) {
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
@@ -1150,7 +1160,7 @@ int insert_inode_locked(struct inode *inode)
spin_unlock(&inode_lock);
return 0;
}
- __iget(old);
+ atomic_inc(&old->i_count);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
@@ -1189,7 +1199,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
spin_unlock(&inode_lock);
return 0;
}
- __iget(old);
+ atomic_inc(&old->i_count);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index ed78a3c..797a034 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -289,7 +289,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
mutex_unlock(&f->sem);
d_instantiate(dentry, old_dentry->d_inode);
dir_i->i_mtime = dir_i->i_ctime = ITIME(now);
- atomic_inc(&old_dentry->d_inode->i_count);
+ iref(old_dentry->d_inode);
}
return ret;
}
@@ -864,7 +864,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
printk(KERN_NOTICE "jffs2_rename(): Link succeeded, unlink failed (err %d). You now have a hard link\n", ret);
/* Might as well let the VFS know */
d_instantiate(new_dentry, old_dentry->d_inode);
- atomic_inc(&old_dentry->d_inode->i_count);
+ iref(old_dentry->d_inode);
new_dir_i->i_mtime = new_dir_i->i_ctime = ITIME(now);
return ret;
}
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index d945ea7..3e6dd08 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -1279,7 +1279,7 @@ int txCommit(tid_t tid, /* transaction identifier */
* lazy commit thread finishes processing
*/
if (tblk->xflag & COMMIT_DELETE) {
- atomic_inc(&tblk->u.ip->i_count);
+ iref(tblk->u.ip);
/*
* Avoid a rare deadlock
*
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index a9cf8e8..3d3566e 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -839,7 +839,7 @@ static int jfs_link(struct dentry *old_dentry,
ip->i_ctime = CURRENT_TIME;
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
mark_inode_dirty(dir);
- atomic_inc(&ip->i_count);
+ iref(ip);
iplist[0] = ip;
iplist[1] = dir;
diff --git a/fs/libfs.c b/fs/libfs.c
index 0a9da95..f190d73 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -255,7 +255,7 @@ int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *den
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
inc_nlink(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
dget(dentry);
d_instantiate(dentry, inode);
return 0;
diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c
index 9777eb5..8522edc 100644
--- a/fs/logfs/dir.c
+++ b/fs/logfs/dir.c
@@ -569,7 +569,7 @@ static int logfs_link(struct dentry *old_dentry, struct inode *dir,
return -EMLINK;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
- atomic_inc(&inode->i_count);
+ iref(inode);
inode->i_nlink++;
mark_inode_dirty_sync(inode);
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index f3f3578..7563a82 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -101,7 +101,7 @@ static int minix_link(struct dentry * old_dentry, struct inode * dir,
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
return add_nondir(dentry, inode);
}
diff --git a/fs/namei.c b/fs/namei.c
index 24896e8..5fb93f3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2291,7 +2291,7 @@ static long do_unlinkat(int dfd, const char __user *pathname)
goto slashes;
inode = dentry->d_inode;
if (inode)
- atomic_inc(&inode->i_count);
+ iref(inode);
error = mnt_want_write(nd.path.mnt);
if (error)
goto exit2;
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e257172..5482ede 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1580,7 +1580,7 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
d_drop(dentry);
error = NFS_PROTO(dir)->link(inode, dir, &dentry->d_name);
if (error == 0) {
- atomic_inc(&inode->i_count);
+ iref(inode);
d_add(dentry, inode);
}
return error;
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index a70e446..5aaa2be 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -55,7 +55,7 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
return -ENOMEM;
}
/* Circumvent igrab(): we know the inode is not being freed */
- atomic_inc(&inode->i_count);
+ iref(inode);
/*
* Ensure that this dentry is invisible to d_find_alias().
* Otherwise, it may be spliced into the tree by
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 874972d..d1c2f08 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -390,7 +390,7 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
BUG_ON(error);
if (!nfsi->npages) {
- igrab(inode);
+ iref(inode);
if (nfs_have_delegation(inode, FMODE_WRITE))
nfsi->change_attr++;
}
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index ad6ed2c..fbd3348 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -219,7 +219,7 @@ static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
inode->i_ctime = CURRENT_TIME;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
err = nilfs_add_nondir(dentry, inode);
if (!err)
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 33297c0..fa7f3b8 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -244,7 +244,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
struct inode *need_iput_tmp;
/*
- * We cannot __iget() an inode in state I_FREEING,
+ * We cannot iref() an inode in state I_FREEING,
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
@@ -253,7 +253,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
/*
* If i_count is zero, the inode cannot have any watches and
- * doing an __iget/iput with MS_ACTIVE clear would actually
+ * doing an iref/iput with MS_ACTIVE clear would actually
* evict all inodes with zero i_count from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
@@ -265,7 +265,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
/* In case fsnotify_inode_delete() drops a reference. */
if (inode != need_iput_tmp)
- __iget(inode);
+ atomic_inc(&inode->i_count);
else
need_iput_tmp = NULL;
@@ -273,7 +273,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
if ((&next_i->i_sb_list != list) &&
atomic_read(&next_i->i_count) &&
!(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
- __iget(next_i);
+ atomic_inc(&next_i->i_count);
need_iput = next_i;
}
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 5128061..52b48e3 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2929,8 +2929,8 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
goto unl_upcase_iput_tmp_ino_err_out_now;
}
if ((sb->s_root = d_alloc_root(vol->root_ino))) {
- /* We increment i_count simulating an ntfs_iget(). */
- atomic_inc(&vol->root_ino->i_count);
+ /* Simulate an ntfs_iget() call */
+ iref(vol->root_ino);
ntfs_debug("Exiting, status successful.");
/* Release the default upcase if it has no users. */
mutex_lock(&ntfs_lock);
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index a00dda2..0e002f6 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -741,7 +741,7 @@ static int ocfs2_link(struct dentry *old_dentry,
goto out_commit;
}
- atomic_inc(&inode->i_count);
+ iref(inode);
dentry->d_op = &ocfs2_dentry_ops;
d_instantiate(dentry, inode);
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index aad1316..38d4304 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -909,7 +909,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
if (!dqinit_needed(inode, type))
continue;
- __iget(inode);
+ atomic_inc(&inode->i_count);
spin_unlock(&inode_lock);
iput(old_inode);
diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index ee78d4a..f19bb3d 100644
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -1156,7 +1156,7 @@ static int reiserfs_link(struct dentry *old_dentry, struct inode *dir,
inode->i_ctime = CURRENT_TIME_SEC;
reiserfs_update_sd(&th, inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(dentry, inode);
retval = journal_end(&th, dir->i_sb, jbegin_count);
reiserfs_write_unlock(dir->i_sb);
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index 33e047b..765974f 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -126,7 +126,7 @@ static int sysv_link(struct dentry * old_dentry, struct inode * dir,
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
return add_nondir(dentry, inode);
}
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 87ebcce..9e8281f 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -550,7 +550,7 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
lock_2_inodes(dir, inode);
inc_nlink(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
inode->i_ctime = ubifs_current_time(inode);
dir->i_size += sz_change;
dir_ui->ui_size = dir->i_size;
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index bf5fc67..f6e232a 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -1101,7 +1101,7 @@ static int udf_link(struct dentry *old_dentry, struct inode *dir,
inc_nlink(inode);
inode->i_ctime = current_fs_time(inode->i_sb);
mark_inode_dirty(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(dentry, inode);
unlock_kernel();
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index b056f02..2a598eb 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -180,7 +180,7 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
- atomic_inc(&inode->i_count);
+ iref(inode);
error = ufs_add_nondir(dentry, inode);
unlock_kernel();
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index b1fc2a6..b7ec465 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -352,7 +352,7 @@ xfs_vn_link(
if (unlikely(error))
return -error;
- atomic_inc(&inode->i_count);
+ iref(inode);
d_instantiate(dentry, inode);
return 0;
}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 0898c54..cbb4791 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -482,7 +482,7 @@ void xfs_mark_inode_dirty_sync(xfs_inode_t *);
#define IHOLD(ip) \
do { \
ASSERT(atomic_read(&VFS_I(ip)->i_count) > 0) ; \
- atomic_inc(&(VFS_I(ip)->i_count)); \
+ iref(VFS_I(ip)); \
trace_xfs_ihold(ip, _THIS_IP_); \
} while (0)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 90d2b47..6eb94b0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2184,7 +2184,7 @@ extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struc
extern int insert_inode_locked(struct inode *);
extern void unlock_new_inode(struct inode *);
-extern void __iget(struct inode * inode);
+extern void iref(struct inode *inode);
extern void iget_failed(struct inode *);
extern void end_writeback(struct inode *);
extern void destroy_inode(struct inode *);
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index c60e519..d53a2c1 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -769,7 +769,7 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
inode = dentry->d_inode;
if (inode)
- atomic_inc(&inode->i_count);
+ iref(inode);
err = mnt_want_write(ipc_ns->mq_mnt);
if (err)
goto out_err;
diff --git a/kernel/futex.c b/kernel/futex.c
index 6a3a5fa..3bb418c 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -168,7 +168,7 @@ static void get_futex_key_refs(union futex_key *key)
switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
case FUT_OFF_INODE:
- atomic_inc(&key->shared.inode->i_count);
+ iref(key->shared.inode);
break;
case FUT_OFF_MMSHARED:
atomic_inc(&key->private.mm->mm_count);
diff --git a/mm/shmem.c b/mm/shmem.c
index 080b09a..7d0bc16 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1903,7 +1903,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
dir->i_size += BOGO_DIRENT_SIZE;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
inc_nlink(inode);
- atomic_inc(&inode->i_count); /* New dentry reference */
+ iref(inode);
dget(dentry); /* Extra pinning count for the created dentry */
d_instantiate(dentry, inode);
out:
diff --git a/net/socket.c b/net/socket.c
index 2270b94..715ca57 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -377,7 +377,7 @@ static int sock_alloc_file(struct socket *sock, struct file **f, int flags)
&socket_file_ops);
if (unlikely(!file)) {
/* drop dentry, keep inode */
- atomic_inc(&path.dentry->d_inode->i_count);
+ iref(path.dentry->d_inode);
path_put(&path);
put_unused_fd(fd);
return -ENFILE;
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 06/18] exofs: use iput() for inode reference count decrements
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (4 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 05/18] fs: Clean up inode reference counting Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 11:34 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 07/18] fs: rework icount to be a locked variable Dave Chinner
` (12 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
Direct modification of the inode reference count is a no-no. Convert
the exofs decrements to call iput() instead of acting directly on
i_count.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/exofs/inode.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index b631ff3..0fb4d4c 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1101,7 +1101,7 @@ static void create_done(struct exofs_io_state *ios, void *p)
set_obj_created(oi);
- atomic_dec(&inode->i_count);
+ iput(inode);
wake_up(&oi->i_wq);
}
@@ -1161,7 +1161,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
ios->cred = oi->i_cred;
ret = exofs_sbi_create(ios);
if (ret) {
- atomic_dec(&inode->i_count);
+ iput(inode);
exofs_put_io_state(ios);
return ERR_PTR(ret);
}
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 07/18] fs: rework icount to be a locked variable
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (5 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 06/18] exofs: use iput() for inode reference count decrements Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 11:36 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 08/18] fs: Factor inode hash operations into functions Dave Chinner
` (11 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
The inode reference count is currently an atomic variable so that it can be
sampled/modified outside the inode_lock. However, the inode_lock is still
needed to synchronise the final reference count and checks against the inode
state.
To avoid needing the protection of the inode lock, protect the inode reference
count with the per-inode i_lock and convert it to a normal variable. To avoid
existing out-of-tree code accidentally compiling against the new method, rename
the i_count field to i_ref. This is relatively straight forward as there
are limited external references to the i_count field remaining.
Based on work originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/btrfs/inode.c | 14 +++++--
fs/ceph/mds_client.c | 2 +-
fs/cifs/inode.c | 2 +-
fs/drop_caches.c | 4 ++-
fs/ext3/ialloc.c | 4 +-
fs/ext4/ialloc.c | 4 +-
fs/fs-writeback.c | 10 ++++--
fs/hpfs/inode.c | 2 +-
fs/inode.c | 81 +++++++++++++++++++++++++++++++-----------
fs/locks.c | 2 +-
fs/logfs/readwrite.c | 2 +-
fs/nfs/inode.c | 4 +-
fs/nfs/nfs4state.c | 2 +-
fs/nilfs2/mdt.c | 2 +-
fs/notify/inode_mark.c | 25 ++++++++-----
fs/ntfs/inode.c | 6 ++--
fs/ntfs/super.c | 2 +-
fs/quota/dquot.c | 4 ++-
fs/reiserfs/stree.c | 2 +-
fs/smbfs/inode.c | 2 +-
fs/ubifs/super.c | 2 +-
fs/udf/inode.c | 2 +-
fs/xfs/linux-2.6/xfs_trace.h | 2 +-
fs/xfs/xfs_inode.h | 1 -
include/linux/fs.h | 2 +-
25 files changed, 122 insertions(+), 63 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 80e28bf..7947bf0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1964,8 +1964,14 @@ void btrfs_add_delayed_iput(struct inode *inode)
struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
struct delayed_iput *delayed;
- if (atomic_add_unless(&inode->i_count, -1, 1))
+ /* XXX: filesystems should not play refcount games like this */
+ spin_lock(&inode->i_lock);
+ if (inode->i_ref > 1) {
+ inode->i_ref--;
+ spin_unlock(&inode->i_lock);
return;
+ }
+ spin_unlock(&inode->i_lock);
delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
delayed->inode = inode;
@@ -2718,10 +2724,10 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
return ERR_PTR(-ENOSPC);
/* check if there is someone else holds reference */
- if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
+ if (S_ISDIR(inode->i_mode) && inode->i_ref > 1)
return ERR_PTR(-ENOSPC);
- if (atomic_read(&inode->i_count) > 2)
+ if (inode->i_ref > 2)
return ERR_PTR(-ENOSPC);
if (xchg(&root->fs_info->enospc_unlink, 1))
@@ -3939,7 +3945,7 @@ again:
inode = igrab(&entry->vfs_inode);
if (inode) {
spin_unlock(&root->inode_lock);
- if (atomic_read(&inode->i_count) > 1)
+ if (inode->i_ref > 1)
d_prune_aliases(inode);
/*
* btrfs_drop_inode will have it removed from
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index fad95f8..1217580 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1102,7 +1102,7 @@ static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
spin_unlock(&inode->i_lock);
d_prune_aliases(inode);
dout("trim_caps_cb %p cap %p pruned, count now %d\n",
- inode, cap, atomic_read(&inode->i_count));
+ inode, cap, inode->i_ref);
return 0;
}
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 53cce8c..f13f2d0 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1641,7 +1641,7 @@ int cifs_revalidate_dentry(struct dentry *dentry)
}
cFYI(1, "Revalidate: %s inode 0x%p count %d dentry: 0x%p d_time %ld "
- "jiffies %ld", full_path, inode, inode->i_count.counter,
+ "jiffies %ld", full_path, inode, inode->i_ref,
dentry, dentry->d_time, jiffies);
if (CIFS_SB(sb)->tcon->unix_ext)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index c2721fa..10c8c5a 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -22,7 +22,9 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
continue;
if (inode->i_mapping->nrpages == 0)
continue;
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
diff --git a/fs/ext3/ialloc.c b/fs/ext3/ialloc.c
index 4ab72db..fb20ac7 100644
--- a/fs/ext3/ialloc.c
+++ b/fs/ext3/ialloc.c
@@ -100,9 +100,9 @@ void ext3_free_inode (handle_t *handle, struct inode * inode)
struct ext3_sb_info *sbi;
int fatal = 0, err;
- if (atomic_read(&inode->i_count) > 1) {
+ if (inode->i_ref > 1) {
printk ("ext3_free_inode: inode has count=%d\n",
- atomic_read(&inode->i_count));
+ inode->i_ref);
return;
}
if (inode->i_nlink) {
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 45853e0..56d0bb0 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -189,9 +189,9 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
struct ext4_sb_info *sbi;
int fatal = 0, err, count, cleared;
- if (atomic_read(&inode->i_count) > 1) {
+ if (inode->i_ref > 1) {
printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
- atomic_read(&inode->i_count));
+ inode->i_ref);
return;
}
if (inode->i_nlink) {
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 8fb092a..be40b8d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -315,7 +315,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty;
int ret;
- if (!atomic_read(&inode->i_count))
+ if (!inode->i_ref)
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
WARN_ON(inode->i_state & I_WILL_FREE);
@@ -493,7 +493,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
return 1;
BUG_ON(inode->i_state & I_FREEING);
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
@@ -1039,7 +1041,9 @@ static void wait_sb_inodes(struct super_block *sb)
mapping = inode->i_mapping;
if (mapping->nrpages == 0)
continue;
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
index 56f0da1..67147bf 100644
--- a/fs/hpfs/inode.c
+++ b/fs/hpfs/inode.c
@@ -183,7 +183,7 @@ void hpfs_write_inode(struct inode *i)
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct inode *parent;
if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
- if (hpfs_inode->i_rddir_off && !atomic_read(&i->i_count)) {
+ if (hpfs_inode->i_rddir_off && !i->i_ref) {
if (*hpfs_inode->i_rddir_off) printk("HPFS: write_inode: some position still there\n");
kfree(hpfs_inode->i_rddir_off);
hpfs_inode->i_rddir_off = NULL;
diff --git a/fs/inode.c b/fs/inode.c
index ee242c1..9f7d284 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -26,6 +26,13 @@
#include <linux/posix_acl.h>
/*
+ * Locking rules.
+ *
+ * inode->i_lock protects:
+ * i_ref
+ */
+
+/*
* This is needed for the following functions:
* - inode_has_buffers
* - invalidate_inode_buffers
@@ -64,9 +71,9 @@ static unsigned int i_hash_shift __read_mostly;
* Each inode can be on two separate lists. One is
* the hash list of the inode, used for lookups. The
* other linked list is the "type" list:
- * "in_use" - valid inode, i_count > 0, i_nlink > 0
+ * "in_use" - valid inode, i_ref > 0, i_nlink > 0
* "dirty" - as "in_use" but also dirty
- * "unused" - valid inode, i_count = 0
+ * "unused" - valid inode, i_ref = 0
*
* A "dirty" list is maintained for each super block,
* allowing for low-overhead inode sync() operations.
@@ -164,7 +171,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_sb = sb;
inode->i_blkbits = sb->s_blocksize_bits;
inode->i_flags = 0;
- atomic_set(&inode->i_count, 1);
+ inode->i_ref = 1;
inode->i_op = &empty_iops;
inode->i_fop = &empty_fops;
inode->i_nlink = 1;
@@ -325,9 +332,11 @@ static void init_once(void *foo)
*/
void iref(struct inode *inode)
{
- WARN_ON(atomic_read(&inode->i_count < 1));
+ WARN_ON(inode->i_ref < 1);
spin_lock(&inode_lock);
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(iref);
@@ -432,13 +441,16 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
if (inode->i_state & I_NEW)
continue;
invalidate_inode_buffers(inode);
- if (!atomic_read(&inode->i_count)) {
+ spin_lock(&inode->i_lock);
+ if (!inode->i_ref) {
+ spin_unlock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
list_move(&inode->i_lru, dispose);
percpu_counter_dec(&nr_inodes_unused);
continue;
}
+ spin_unlock(&inode->i_lock);
busy = 1;
}
return busy;
@@ -476,7 +488,7 @@ static int can_unuse(struct inode *inode)
return 0;
if (inode_has_buffers(inode))
return 0;
- if (atomic_read(&inode->i_count))
+ if (inode->i_ref)
return 0;
if (inode->i_data.nrpages)
return 0;
@@ -519,8 +531,9 @@ static void prune_icache(int nr_to_scan)
* Referenced or dirty inodes are still in use. Give them
* another pass through the LRU as we canot reclaim them now.
*/
- if (atomic_read(&inode->i_count) ||
- (inode->i_state & ~I_REFERENCED)) {
+ spin_lock(&inode->i_lock);
+ if (inode->i_ref || (inode->i_state & ~I_REFERENCED)) {
+ spin_unlock(&inode->i_lock);
list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
continue;
@@ -528,12 +541,14 @@ static void prune_icache(int nr_to_scan)
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
+ spin_unlock(&inode->i_lock);
list_move(&inode->i_lru, &inode_lru);
inode->i_state &= ~I_REFERENCED;
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
- atomic_inc(&inode->i_count);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
@@ -550,7 +565,8 @@ static void prune_icache(int nr_to_scan)
list_move(&inode->i_lru, &inode_lru);
continue;
}
- }
+ } else
+ spin_unlock(&inode->i_lock);
list_move(&inode->i_lru, &freeable);
list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
@@ -803,7 +819,9 @@ static struct inode *get_new_inode(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- atomic_inc(&old->i_count);
+ spin_lock(&old->i_lock);
+ old->i_ref++;
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -850,7 +868,9 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- atomic_inc(&old->i_count);
+ spin_lock(&old->i_lock);
+ old->i_ref++;
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
@@ -902,15 +922,19 @@ EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
spin_lock(&inode_lock);
- if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
- atomic_inc(&inode->i_count);
- else
+ spin_lock(&inode->i_lock);
+ if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
+ } else {
+ spin_unlock(&inode->i_lock);
/*
* Handle the case where s_op->clear_inode is not been
* called yet, and somebody is calling igrab
* while the inode is getting freed.
*/
inode = NULL;
+ }
spin_unlock(&inode_lock);
return inode;
}
@@ -944,7 +968,9 @@ static struct inode *ifind(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode(sb, head, test, data);
if (inode) {
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
if (likely(wait))
wait_on_inode(inode);
@@ -977,7 +1003,9 @@ static struct inode *ifind_fast(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode_fast(sb, head, ino);
if (inode) {
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
@@ -1160,7 +1188,9 @@ int insert_inode_locked(struct inode *inode)
spin_unlock(&inode_lock);
return 0;
}
- atomic_inc(&old->i_count);
+ spin_lock(&old->i_lock);
+ old->i_ref++;
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
@@ -1199,7 +1229,9 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
spin_unlock(&inode_lock);
return 0;
}
- atomic_inc(&old->i_count);
+ spin_lock(&old->i_lock);
+ old->i_ref++;
+ spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!hlist_unhashed(&old->i_hash))) {
@@ -1333,8 +1365,15 @@ void iput(struct inode *inode)
if (inode) {
BUG_ON(inode->i_state & I_CLEAR);
- if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
+ spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
+ if (--inode->i_ref == 0) {
+ spin_unlock(&inode->i_lock);
iput_final(inode);
+ return;
+ }
+ spin_unlock(&inode->i_lock);
+ spin_lock(&inode_lock);
}
}
EXPORT_SYMBOL(iput);
diff --git a/fs/locks.c b/fs/locks.c
index ab24d49..4dec81a 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1376,7 +1376,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
goto out;
if ((arg == F_WRLCK)
&& ((atomic_read(&dentry->d_count) > 1)
- || (atomic_read(&inode->i_count) > 1)))
+ || inode->i_ref > 1))
goto out;
}
diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c
index 6127baf..1b26a8d 100644
--- a/fs/logfs/readwrite.c
+++ b/fs/logfs/readwrite.c
@@ -1002,7 +1002,7 @@ static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
{
struct logfs_inode *li = logfs_inode(inode);
- if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
+ if ((inode->i_nlink == 0) && inode->i_ref == 1)
return 0;
if (bix < I0_BLOCKS)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 7d2d6c7..32a9c69 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -384,7 +384,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
dprintk("NFS: nfs_fhget(%s/%Ld ct=%d)\n",
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
- atomic_read(&inode->i_count));
+ inode->i_ref);
out:
return inode;
@@ -1190,7 +1190,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
dfprintk(VFS, "NFS: %s(%s/%ld ct=%d info=0x%x)\n",
__func__, inode->i_sb->s_id, inode->i_ino,
- atomic_read(&inode->i_count), fattr->valid);
+ inode->i_ref, fattr->valid);
if ((fattr->valid & NFS_ATTR_FATTR_FILEID) && nfsi->fileid != fattr->fileid)
goto out_fileid;
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 3e2f19b..d7fc5d0 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -506,8 +506,8 @@ nfs4_get_open_state(struct inode *inode, struct nfs4_state_owner *owner)
state->owner = owner;
atomic_inc(&owner->so_count);
list_add(&state->inode_states, &nfsi->open_states);
- state->inode = igrab(inode);
spin_unlock(&inode->i_lock);
+ state->inode = igrab(inode);
/* Note: The reclaim code dictates that we add stateless
* and read-only stateids to the end of the list */
list_add_tail(&state->open_states, &owner->so_states);
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 62756b4..939459d 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -480,7 +480,7 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
inode->i_sb = sb; /* sb may be NULL for some meta data files */
inode->i_blkbits = nilfs->ns_blocksize_bits;
inode->i_flags = 0;
- atomic_set(&inode->i_count, 1);
+ inode->i_ref = 1;
inode->i_nlink = 1;
inode->i_ino = ino;
inode->i_mode = S_IFREG;
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index fa7f3b8..1a4c117 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -252,29 +252,36 @@ void fsnotify_unmount_inodes(struct list_head *list)
continue;
/*
- * If i_count is zero, the inode cannot have any watches and
+ * If i_ref is zero, the inode cannot have any watches and
* doing an iref/iput with MS_ACTIVE clear would actually
- * evict all inodes with zero i_count from icache which is
+ * evict all inodes with zero i_ref from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- if (!atomic_read(&inode->i_count))
+ spin_lock(&inode->i_lock);
+ if (!inode->i_ref) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
need_iput_tmp = need_iput;
need_iput = NULL;
/* In case fsnotify_inode_delete() drops a reference. */
if (inode != need_iput_tmp)
- atomic_inc(&inode->i_count);
+ inode->i_ref++;
else
need_iput_tmp = NULL;
+ spin_unlock(&inode->i_lock);
/* In case the dropping of a reference would nuke next_i. */
- if ((&next_i->i_sb_list != list) &&
- atomic_read(&next_i->i_count) &&
- !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
- atomic_inc(&next_i->i_count);
- need_iput = next_i;
+ if (&next_i->i_sb_list != list) {
+ spin_lock(&next_i->i_lock);
+ if (inode->i_ref &&
+ !(next_i->i_state & (I_FREEING | I_WILL_FREE))) {
+ next_i->i_ref++;
+ need_iput = next_i;
+ }
+ spin_unlock(&next_i->i_lock);
}
/*
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 93622b1..07fdef8 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -531,7 +531,7 @@ err_corrupt_attr:
*
* Q: What locks are held when the function is called?
* A: i_state has I_NEW set, hence the inode is locked, also
- * i_count is set to 1, so it is not going to go away
+ * i_ref is set to 1, so it is not going to go away
* i_flags is set to 0 and we have no business touching it. Only an ioctl()
* is allowed to write to them. We should of course be honouring them but
* we need to do that using the IS_* macros defined in include/linux/fs.h.
@@ -1208,7 +1208,7 @@ err_out:
*
* Q: What locks are held when the function is called?
* A: i_state has I_NEW set, hence the inode is locked, also
- * i_count is set to 1, so it is not going to go away
+ * i_ref is set to 1, so it is not going to go away
*
* Return 0 on success and -errno on error. In the error case, the inode will
* have had make_bad_inode() executed on it.
@@ -1475,7 +1475,7 @@ err_out:
*
* Q: What locks are held when the function is called?
* A: i_state has I_NEW set, hence the inode is locked, also
- * i_count is set to 1, so it is not going to go away
+ * i_ref is set to 1, so it is not going to go away
*
* Return 0 on success and -errno on error. In the error case, the inode will
* have had make_bad_inode() executed on it.
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 52b48e3..181eddb 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -2689,7 +2689,7 @@ static const struct super_operations ntfs_sops = {
// held. See fs/inode.c::
// generic_drop_inode(). */
//.delete_inode = NULL, /* VFS: Delete inode from disk.
- // Called when i_count becomes
+ // Called when i_ref becomes
// 0 and i_nlink is also 0. */
//.write_super = NULL, /* Flush dirty super block to
// disk. */
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 38d4304..326df72 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -909,7 +909,9 @@ static void add_dquot_ref(struct super_block *sb, int type)
if (!dqinit_needed(inode, type))
continue;
- atomic_inc(&inode->i_count);
+ spin_lock(&inode->i_lock);
+ inode->i_ref++;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
iput(old_inode);
diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index 313d39d..42d3311 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1477,7 +1477,7 @@ static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
** reading in the last block. The user will hit problems trying to
** read the file, but for now we just skip the indirect2direct
*/
- if (atomic_read(&inode->i_count) > 1 ||
+ if (inode->i_ref > 1 ||
!tail_has_to_be_packed(inode) ||
!page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
/* leave tail in an unformatted node */
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 450c919..85ff606 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -320,7 +320,7 @@ out:
}
/*
- * This routine is called when i_nlink == 0 and i_count goes to 0.
+ * This routine is called when i_nlink == 0 and i_ref goes to 0.
* All blocking cleanup operations need to go here to avoid races.
*/
static void
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index cd5900b..ead1f89 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -342,7 +342,7 @@ static void ubifs_evict_inode(struct inode *inode)
goto out;
dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
- ubifs_assert(!atomic_read(&inode->i_count));
+ ubifs_assert(!inode->i_ref);
truncate_inode_pages(&inode->i_data, 0);
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index fc48f37..05b0445 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1071,7 +1071,7 @@ static void __udf_read_inode(struct inode *inode)
* i_flags = sb->s_flags
* i_state = 0
* clean_inode(): zero fills and sets
- * i_count = 1
+ * i_ref = 1
* i_nlink = 1
* i_op = NULL;
*/
diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index be5dffd..0428b06 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -599,7 +599,7 @@ DECLARE_EVENT_CLASS(xfs_iref_class,
TP_fast_assign(
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
- __entry->count = atomic_read(&VFS_I(ip)->i_count);
+ __entry->count = VFS_I(ip)->i_ref;
__entry->pincount = atomic_read(&ip->i_pincount);
__entry->caller_ip = caller_ip;
),
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index cbb4791..1e41fa8 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -481,7 +481,6 @@ void xfs_mark_inode_dirty_sync(xfs_inode_t *);
#define IHOLD(ip) \
do { \
- ASSERT(atomic_read(&VFS_I(ip)->i_count) > 0) ; \
iref(VFS_I(ip)); \
trace_xfs_ihold(ip, _THIS_IP_); \
} while (0)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6eb94b0..0b6ee34 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -730,7 +730,7 @@ struct inode {
struct list_head i_sb_list;
struct list_head i_dentry;
unsigned long i_ino;
- atomic_t i_count;
+ unsigned int i_ref;
unsigned int i_nlink;
uid_t i_uid;
gid_t i_gid;
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 08/18] fs: Factor inode hash operations into functions
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (6 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 07/18] fs: rework icount to be a locked variable Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 09/18] fs: Introduce per-bucket inode hash locks Dave Chinner
` (10 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
Before replacing the inode hash locking with a more scalable
mechanism, factor the removal of the inode from the hashes rather
than open coding it in several places.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/inode.c | 100 +++++++++++++++++++++++++++++++++--------------------------
1 files changed, 56 insertions(+), 44 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 9f7d284..f595542 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -357,6 +357,59 @@ void inode_lru_list_del(struct inode *inode)
}
}
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+ unsigned long tmp;
+
+ tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+ L1_CACHE_BYTES;
+ tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
+ return tmp & I_HASHMASK;
+}
+
+/**
+ * __insert_inode_hash - hash an inode
+ * @inode: unhashed inode
+ * @hashval: unsigned long value used to locate this object in the
+ * inode_hashtable.
+ *
+ * Add an inode to the inode hash for this superblock.
+ */
+void __insert_inode_hash(struct inode *inode, unsigned long hashval)
+{
+ struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+ spin_lock(&inode_lock);
+ hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(__insert_inode_hash);
+
+/**
+ * __remove_inode_hash - remove an inode from the hash
+ * @inode: inode to unhash
+ *
+ * Remove an inode from the superblock. inode->i_lock must be
+ * held.
+ */
+static void __remove_inode_hash(struct inode *inode)
+{
+ hlist_del_init(&inode->i_hash);
+}
+
+/**
+ * remove_inode_hash - remove an inode from the hash
+ * @inode: inode to unhash
+ *
+ * Remove an inode from the superblock.
+ */
+void remove_inode_hash(struct inode *inode)
+{
+ spin_lock(&inode_lock);
+ hlist_del_init(&inode->i_hash);
+ spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(remove_inode_hash);
+
void end_writeback(struct inode *inode)
{
might_sleep();
@@ -404,7 +457,7 @@ static void dispose_list(struct list_head *head)
evict(inode);
spin_lock(&inode_lock);
- hlist_del_init(&inode->i_hash);
+ __remove_inode_hash(inode);
list_del_init(&inode->i_sb_list);
spin_unlock(&inode_lock);
@@ -667,16 +720,6 @@ repeat:
return node ? inode : NULL;
}
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
- unsigned long tmp;
-
- tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
- L1_CACHE_BYTES;
- tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
- return tmp & I_HASHMASK;
-}
-
static inline void
__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
struct inode *inode)
@@ -1243,36 +1286,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
}
EXPORT_SYMBOL(insert_inode_locked4);
-/**
- * __insert_inode_hash - hash an inode
- * @inode: unhashed inode
- * @hashval: unsigned long value used to locate this object in the
- * inode_hashtable.
- *
- * Add an inode to the inode hash for this superblock.
- */
-void __insert_inode_hash(struct inode *inode, unsigned long hashval)
-{
- struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
- spin_lock(&inode_lock);
- hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(__insert_inode_hash);
-
-/**
- * remove_inode_hash - remove an inode from the hash
- * @inode: inode to unhash
- *
- * Remove an inode from the superblock.
- */
-void remove_inode_hash(struct inode *inode)
-{
- spin_lock(&inode_lock);
- hlist_del_init(&inode->i_hash);
- spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(remove_inode_hash);
int generic_delete_inode(struct inode *inode)
{
@@ -1328,6 +1341,7 @@ static void iput_final(struct inode *inode)
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
hlist_del_init(&inode->i_hash);
+ __remove_inode_hash(inode);
}
list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
@@ -1343,9 +1357,7 @@ static void iput_final(struct inode *inode)
list_del_init(&inode->i_sb_list);
spin_unlock(&inode_lock);
evict(inode);
- spin_lock(&inode_lock);
- hlist_del_init(&inode->i_hash);
- spin_unlock(&inode_lock);
+ remove_inode_hash(inode);
wake_up_inode(inode);
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
destroy_inode(inode);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 09/18] fs: Introduce per-bucket inode hash locks
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (7 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 08/18] fs: Factor inode hash operations into functions Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 11:41 ` Christoph Hellwig
2010-10-13 15:05 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 10/18] fs: add a per-superblock lock for the inode list Dave Chinner
` (9 subsequent siblings)
18 siblings, 2 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
Protect the inode hash with a single lock is not scalable. Convert
the inode hash to use the new bit-locked hash list implementation
that allows per-bucket locks to be used. This allows us to replace
the global inode_lock with finer grained locking without increasing
the size of the hash table.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/btrfs/inode.c | 2 +-
fs/fs-writeback.c | 2 +-
fs/hfs/hfs_fs.h | 2 +-
fs/hfs/inode.c | 2 +-
fs/hfsplus/hfsplus_fs.h | 2 +-
fs/hfsplus/inode.c | 2 +-
fs/inode.c | 149 ++++++++++++++++++++++++++++------------------
fs/nilfs2/gcinode.c | 22 ++++---
fs/nilfs2/segment.c | 2 +-
fs/nilfs2/the_nilfs.h | 2 +-
fs/reiserfs/xattr.c | 2 +-
include/linux/fs.h | 8 ++-
include/linux/list_bl.h | 18 ++++++
mm/shmem.c | 4 +-
14 files changed, 139 insertions(+), 80 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7947bf0..c7a2bef 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3855,7 +3855,7 @@ again:
p = &root->inode_tree.rb_node;
parent = NULL;
- if (hlist_unhashed(&inode->i_hash))
+ if (inode_unhashed(inode))
return;
spin_lock(&root->inode_lock);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index be40b8d..31d7f35 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -958,7 +958,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
* dirty list. Add blockdev inodes as well.
*/
if (!S_ISBLK(inode->i_mode)) {
- if (hlist_unhashed(&inode->i_hash))
+ if (inode_unhashed(inode))
goto out;
}
if (inode->i_state & I_FREEING)
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index 4f55651..24591be 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -148,7 +148,7 @@ struct hfs_sb_info {
int fs_div;
- struct hlist_head rsrc_inodes;
+ struct hlist_bl_head rsrc_inodes;
};
#define HFS_FLG_BITMAP_DIRTY 0
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 397b7ad..7778298 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -524,7 +524,7 @@ static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
HFS_I(inode)->rsrc_inode = dir;
HFS_I(dir)->rsrc_inode = inode;
igrab(dir);
- hlist_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
+ hlist_bl_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
mark_inode_dirty(inode);
out:
d_add(dentry, inode);
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index dc856be..499f5a5 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -144,7 +144,7 @@ struct hfsplus_sb_info {
unsigned long flags;
- struct hlist_head rsrc_inodes;
+ struct hlist_bl_head rsrc_inodes;
};
#define HFSPLUS_SB_WRITEBACKUP 0x0001
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index c5a979d..b755cf0 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -202,7 +202,7 @@ static struct dentry *hfsplus_file_lookup(struct inode *dir, struct dentry *dent
HFSPLUS_I(inode).rsrc_inode = dir;
HFSPLUS_I(dir).rsrc_inode = inode;
igrab(dir);
- hlist_add_head(&inode->i_hash, &HFSPLUS_SB(sb).rsrc_inodes);
+ hlist_bl_add_head(&inode->i_hash, &HFSPLUS_SB(sb).rsrc_inodes);
mark_inode_dirty(inode);
out:
d_add(dentry, inode);
diff --git a/fs/inode.c b/fs/inode.c
index f595542..dd3270a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -24,12 +24,20 @@
#include <linux/mount.h>
#include <linux/async.h>
#include <linux/posix_acl.h>
+#include <linux/bit_spinlock.h>
/*
* Locking rules.
*
* inode->i_lock protects:
* i_ref
+ * inode hash lock protects:
+ * inode hash table, i_hash
+ *
+ * Lock orders
+ * inode_lock
+ * inode hash bucket lock
+ * inode->i_lock
*/
/*
@@ -66,6 +74,7 @@
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
+static struct hlist_bl_head *inode_hashtable __read_mostly;
/*
* Each inode can be on two separate lists. One is
@@ -78,9 +87,7 @@ static unsigned int i_hash_shift __read_mostly;
* A "dirty" list is maintained for each super block,
* allowing for low-overhead inode sync() operations.
*/
-
static LIST_HEAD(inode_lru);
-static struct hlist_head *inode_hashtable __read_mostly;
/*
* A simple spinlock to protect the list manipulations.
@@ -295,7 +302,7 @@ void destroy_inode(struct inode *inode)
void inode_init_once(struct inode *inode)
{
memset(inode, 0, sizeof(*inode));
- INIT_HLIST_NODE(&inode->i_hash);
+ init_hlist_bl_node(&inode->i_hash);
INIT_LIST_HEAD(&inode->i_dentry);
INIT_LIST_HEAD(&inode->i_devices);
INIT_LIST_HEAD(&inode->i_wb_list);
@@ -377,9 +384,13 @@ static unsigned long hash(struct super_block *sb, unsigned long hashval)
*/
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
- struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+ struct hlist_bl_head *b;
+
+ b = inode_hashtable + hash(inode->i_sb, hashval);
spin_lock(&inode_lock);
- hlist_add_head(&inode->i_hash, head);
+ hlist_bl_lock(b);
+ hlist_bl_add_head(&inode->i_hash, b);
+ hlist_bl_unlock(b);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
@@ -393,7 +404,12 @@ EXPORT_SYMBOL(__insert_inode_hash);
*/
static void __remove_inode_hash(struct inode *inode)
{
- hlist_del_init(&inode->i_hash);
+ struct hlist_bl_head *b;
+
+ b = inode_hashtable + hash(inode->i_sb, inode->i_ino);
+ hlist_bl_lock(b);
+ hlist_bl_del_init(&inode->i_hash);
+ hlist_bl_unlock(b);
}
/**
@@ -405,7 +421,7 @@ static void __remove_inode_hash(struct inode *inode)
void remove_inode_hash(struct inode *inode)
{
spin_lock(&inode_lock);
- hlist_del_init(&inode->i_hash);
+ __remove_inode_hash(inode);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(remove_inode_hash);
@@ -673,25 +689,28 @@ static void __wait_on_freeing_inode(struct inode *inode);
* add any additional branch in the common code.
*/
static struct inode *find_inode(struct super_block *sb,
- struct hlist_head *head,
+ struct hlist_bl_head *b,
int (*test)(struct inode *, void *),
void *data)
{
- struct hlist_node *node;
+ struct hlist_bl_node *node;
struct inode *inode = NULL;
repeat:
- hlist_for_each_entry(inode, node, head, i_hash) {
+ hlist_bl_lock(b);
+ hlist_bl_for_each_entry(inode, node, b, i_hash) {
if (inode->i_sb != sb)
continue;
if (!test(inode, data))
continue;
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
+ hlist_bl_unlock(b);
__wait_on_freeing_inode(inode);
goto repeat;
}
break;
}
+ hlist_bl_unlock(b);
return node ? inode : NULL;
}
@@ -700,33 +719,40 @@ repeat:
* iget_locked for details.
*/
static struct inode *find_inode_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
+ struct hlist_bl_head *b,
+ unsigned long ino)
{
- struct hlist_node *node;
+ struct hlist_bl_node *node;
struct inode *inode = NULL;
repeat:
- hlist_for_each_entry(inode, node, head, i_hash) {
+ hlist_bl_lock(b);
+ hlist_bl_for_each_entry(inode, node, b, i_hash) {
if (inode->i_ino != ino)
continue;
if (inode->i_sb != sb)
continue;
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
+ hlist_bl_unlock(b);
__wait_on_freeing_inode(inode);
goto repeat;
}
break;
}
+ hlist_bl_unlock(b);
return node ? inode : NULL;
}
static inline void
-__inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
+__inode_add_to_lists(struct super_block *sb, struct hlist_bl_head *b,
struct inode *inode)
{
list_add(&inode->i_sb_list, &sb->s_inodes);
- if (head)
- hlist_add_head(&inode->i_hash, head);
+ if (b) {
+ hlist_bl_lock(b);
+ hlist_bl_add_head(&inode->i_hash, b);
+ hlist_bl_unlock(b);
+ }
}
/**
@@ -743,10 +769,10 @@ __inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
*/
void inode_add_to_lists(struct super_block *sb, struct inode *inode)
{
- struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, inode->i_ino);
spin_lock(&inode_lock);
- __inode_add_to_lists(sb, head, inode);
+ __inode_add_to_lists(sb, b, inode);
spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(inode_add_to_lists);
@@ -829,7 +855,7 @@ EXPORT_SYMBOL(unlock_new_inode);
* -- rmk@arm.uk.linux.org
*/
static struct inode *get_new_inode(struct super_block *sb,
- struct hlist_head *head,
+ struct hlist_bl_head *b,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *),
void *data)
@@ -842,12 +868,12 @@ static struct inode *get_new_inode(struct super_block *sb,
spin_lock(&inode_lock);
/* We released the lock, so.. */
- old = find_inode(sb, head, test, data);
+ old = find_inode(sb, b, test, data);
if (!old) {
if (set(inode, data))
goto set_failed;
- __inode_add_to_lists(sb, head, inode);
+ __inode_add_to_lists(sb, b, inode);
inode->i_state = I_NEW;
spin_unlock(&inode_lock);
@@ -883,7 +909,7 @@ set_failed:
* comment at iget_locked for details.
*/
static struct inode *get_new_inode_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
+ struct hlist_bl_head *b, unsigned long ino)
{
struct inode *inode;
@@ -893,10 +919,10 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
spin_lock(&inode_lock);
/* We released the lock, so.. */
- old = find_inode_fast(sb, head, ino);
+ old = find_inode_fast(sb, b, ino);
if (!old) {
inode->i_ino = ino;
- __inode_add_to_lists(sb, head, inode);
+ __inode_add_to_lists(sb, b, inode);
inode->i_state = I_NEW;
spin_unlock(&inode_lock);
@@ -945,7 +971,7 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
*/
static unsigned int counter;
struct inode *inode;
- struct hlist_head *head;
+ struct hlist_bl_head *b;
ino_t res;
spin_lock(&inode_lock);
@@ -953,8 +979,8 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
if (counter <= max_reserved)
counter = max_reserved + 1;
res = counter++;
- head = inode_hashtable + hash(sb, res);
- inode = find_inode_fast(sb, head, res);
+ b = inode_hashtable + hash(sb, res);
+ inode = find_inode_fast(sb, b, res);
} while (inode != NULL);
spin_unlock(&inode_lock);
@@ -1003,13 +1029,14 @@ EXPORT_SYMBOL(igrab);
* Note, @test is called with the inode_lock held, so can't sleep.
*/
static struct inode *ifind(struct super_block *sb,
- struct hlist_head *head, int (*test)(struct inode *, void *),
+ struct hlist_bl_head *b,
+ int (*test)(struct inode *, void *),
void *data, const int wait)
{
struct inode *inode;
spin_lock(&inode_lock);
- inode = find_inode(sb, head, test, data);
+ inode = find_inode(sb, b, test, data);
if (inode) {
spin_lock(&inode->i_lock);
inode->i_ref++;
@@ -1039,12 +1066,13 @@ static struct inode *ifind(struct super_block *sb,
* Otherwise NULL is returned.
*/
static struct inode *ifind_fast(struct super_block *sb,
- struct hlist_head *head, unsigned long ino)
+ struct hlist_bl_head *b,
+ unsigned long ino)
{
struct inode *inode;
spin_lock(&inode_lock);
- inode = find_inode_fast(sb, head, ino);
+ inode = find_inode_fast(sb, b, ino);
if (inode) {
spin_lock(&inode->i_lock);
inode->i_ref++;
@@ -1081,9 +1109,9 @@ static struct inode *ifind_fast(struct super_block *sb,
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, hashval);
- return ifind(sb, head, test, data, 0);
+ return ifind(sb, b, test, data, 0);
}
EXPORT_SYMBOL(ilookup5_nowait);
@@ -1109,9 +1137,9 @@ EXPORT_SYMBOL(ilookup5_nowait);
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, hashval);
- return ifind(sb, head, test, data, 1);
+ return ifind(sb, b, test, data, 1);
}
EXPORT_SYMBOL(ilookup5);
@@ -1131,9 +1159,9 @@ EXPORT_SYMBOL(ilookup5);
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, ino);
- return ifind_fast(sb, head, ino);
+ return ifind_fast(sb, b, ino);
}
EXPORT_SYMBOL(ilookup);
@@ -1161,17 +1189,17 @@ struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, hashval);
struct inode *inode;
- inode = ifind(sb, head, test, data, 1);
+ inode = ifind(sb, b, test, data, 1);
if (inode)
return inode;
/*
* get_new_inode() will do the right thing, re-trying the search
* in case it had to block at any point.
*/
- return get_new_inode(sb, head, test, set, data);
+ return get_new_inode(sb, b, test, set, data);
}
EXPORT_SYMBOL(iget5_locked);
@@ -1192,17 +1220,17 @@ EXPORT_SYMBOL(iget5_locked);
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, ino);
struct inode *inode;
- inode = ifind_fast(sb, head, ino);
+ inode = ifind_fast(sb, b, ino);
if (inode)
return inode;
/*
* get_new_inode_fast() will do the right thing, re-trying the search
* in case it had to block at any point.
*/
- return get_new_inode_fast(sb, head, ino);
+ return get_new_inode_fast(sb, b, ino);
}
EXPORT_SYMBOL(iget_locked);
@@ -1210,14 +1238,15 @@ int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, ino);
inode->i_state |= I_NEW;
while (1) {
- struct hlist_node *node;
+ struct hlist_bl_node *node;
struct inode *old = NULL;
spin_lock(&inode_lock);
- hlist_for_each_entry(old, node, head, i_hash) {
+ hlist_bl_lock(b);
+ hlist_bl_for_each_entry(old, node, b, i_hash) {
if (old->i_ino != ino)
continue;
if (old->i_sb != sb)
@@ -1227,16 +1256,18 @@ int insert_inode_locked(struct inode *inode)
break;
}
if (likely(!node)) {
- hlist_add_head(&inode->i_hash, head);
+ hlist_bl_add_head(&inode->i_hash, b);
+ hlist_bl_unlock(b);
spin_unlock(&inode_lock);
return 0;
}
spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
+ hlist_bl_unlock(b);
spin_unlock(&inode_lock);
wait_on_inode(old);
- if (unlikely(!hlist_unhashed(&old->i_hash))) {
+ if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
@@ -1249,16 +1280,17 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
struct super_block *sb = inode->i_sb;
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, hashval);
inode->i_state |= I_NEW;
while (1) {
- struct hlist_node *node;
+ struct hlist_bl_node *node;
struct inode *old = NULL;
spin_lock(&inode_lock);
- hlist_for_each_entry(old, node, head, i_hash) {
+ hlist_bl_lock(b);
+ hlist_bl_for_each_entry(old, node, b, i_hash) {
if (old->i_sb != sb)
continue;
if (!test(old, data))
@@ -1268,16 +1300,18 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
break;
}
if (likely(!node)) {
- hlist_add_head(&inode->i_hash, head);
+ hlist_bl_add_head(&inode->i_hash, b);
+ hlist_bl_unlock(b);
spin_unlock(&inode_lock);
return 0;
}
spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
+ hlist_bl_unlock(b);
spin_unlock(&inode_lock);
wait_on_inode(old);
- if (unlikely(!hlist_unhashed(&old->i_hash))) {
+ if (unlikely(!inode_unhashed(old))) {
iput(old);
return -EBUSY;
}
@@ -1300,7 +1334,7 @@ EXPORT_SYMBOL(generic_delete_inode);
*/
int generic_drop_inode(struct inode *inode)
{
- return !inode->i_nlink || hlist_unhashed(&inode->i_hash);
+ return !inode->i_nlink || inode_unhashed(inode);
}
EXPORT_SYMBOL_GPL(generic_drop_inode);
@@ -1340,7 +1374,6 @@ static void iput_final(struct inode *inode)
spin_lock(&inode_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- hlist_del_init(&inode->i_hash);
__remove_inode_hash(inode);
}
list_del_init(&inode->i_wb_list);
@@ -1604,7 +1637,7 @@ void __init inode_init_early(void)
inode_hashtable =
alloc_large_system_hash("Inode-cache",
- sizeof(struct hlist_head),
+ sizeof(struct hlist_bl_head),
ihash_entries,
14,
HASH_EARLY,
@@ -1637,7 +1670,7 @@ void __init inode_init(void)
inode_hashtable =
alloc_large_system_hash("Inode-cache",
- sizeof(struct hlist_head),
+ sizeof(struct hlist_bl_head),
ihash_entries,
14,
0,
@@ -1646,7 +1679,7 @@ void __init inode_init(void)
0);
for (loop = 0; loop < (1 << i_hash_shift); loop++)
- INIT_HLIST_HEAD(&inode_hashtable[loop]);
+ INIT_HLIST_BL_HEAD(&inode_hashtable[loop]);
}
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index bed3a78..ce7344e 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -196,13 +196,13 @@ int nilfs_init_gccache(struct the_nilfs *nilfs)
INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
nilfs->ns_gc_inodes_h =
- kmalloc(sizeof(struct hlist_head) * NILFS_GCINODE_HASH_SIZE,
+ kmalloc(sizeof(struct hlist_bl_head) * NILFS_GCINODE_HASH_SIZE,
GFP_NOFS);
if (nilfs->ns_gc_inodes_h == NULL)
return -ENOMEM;
for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++)
- INIT_HLIST_HEAD(&nilfs->ns_gc_inodes_h[loop]);
+ INIT_HLIST_BL_HEAD(&nilfs->ns_gc_inodes_h[loop]);
return 0;
}
@@ -254,18 +254,18 @@ static unsigned long ihash(ino_t ino, __u64 cno)
*/
struct inode *nilfs_gc_iget(struct the_nilfs *nilfs, ino_t ino, __u64 cno)
{
- struct hlist_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno);
- struct hlist_node *node;
+ struct hlist_bl_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno);
+ struct hlist_bl_node *node;
struct inode *inode;
- hlist_for_each_entry(inode, node, head, i_hash) {
+ hlist_bl_for_each_entry(inode, node, head, i_hash) {
if (inode->i_ino == ino && NILFS_I(inode)->i_cno == cno)
return inode;
}
inode = alloc_gcinode(nilfs, ino, cno);
if (likely(inode)) {
- hlist_add_head(&inode->i_hash, head);
+ hlist_bl_add_head(&inode->i_hash, head);
list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes);
}
return inode;
@@ -284,16 +284,18 @@ void nilfs_clear_gcinode(struct inode *inode)
*/
void nilfs_remove_all_gcinode(struct the_nilfs *nilfs)
{
- struct hlist_head *head = nilfs->ns_gc_inodes_h;
- struct hlist_node *node, *n;
+ struct hlist_bl_head *head = nilfs->ns_gc_inodes_h;
+ struct hlist_bl_node *node;
struct inode *inode;
int loop;
for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++, head++) {
- hlist_for_each_entry_safe(inode, node, n, head, i_hash) {
- hlist_del_init(&inode->i_hash);
+restart:
+ hlist_bl_for_each_entry(inode, node, head, i_hash) {
+ hlist_bl_del_init(&inode->i_hash);
list_del_init(&NILFS_I(inode)->i_dirty);
nilfs_clear_gcinode(inode); /* might sleep */
+ goto restart;
}
}
}
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 9fd051a..038251c 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2452,7 +2452,7 @@ nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
list_for_each_entry_safe(ii, n, head, i_dirty) {
if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
continue;
- hlist_del_init(&ii->vfs_inode.i_hash);
+ hlist_bl_del_init(&ii->vfs_inode.i_hash);
list_del_init(&ii->i_dirty);
nilfs_clear_gcinode(&ii->vfs_inode);
}
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index f785a7b..1ab441a 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -167,7 +167,7 @@ struct the_nilfs {
/* GC inode list and hash table head */
struct list_head ns_gc_inodes;
- struct hlist_head *ns_gc_inodes_h;
+ struct hlist_bl_head *ns_gc_inodes_h;
/* Disk layout information (static) */
unsigned int ns_blocksize_bits;
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 8c4cf27..b246e3c 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -424,7 +424,7 @@ int reiserfs_prepare_write(struct file *f, struct page *page,
static void update_ctime(struct inode *inode)
{
struct timespec now = current_fs_time(inode->i_sb);
- if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink ||
+ if (inode_unhashed(inode) || !inode->i_nlink ||
timespec_equal(&inode->i_ctime, &now))
return;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0b6ee34..67dd926 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -383,6 +383,7 @@ struct inodes_stat_t {
#include <linux/capability.h>
#include <linux/semaphore.h>
#include <linux/fiemap.h>
+#include <linux/list_bl.h>
#include <asm/atomic.h>
#include <asm/byteorder.h>
@@ -724,7 +725,7 @@ struct posix_acl;
#define ACL_NOT_CACHED ((void *)(-1))
struct inode {
- struct hlist_node i_hash;
+ struct hlist_bl_node i_hash;
struct list_head i_wb_list; /* backing dev IO list */
struct list_head i_lru; /* inode LRU list */
struct list_head i_sb_list;
@@ -789,6 +790,11 @@ struct inode {
void *i_private; /* fs or device private pointer */
};
+static inline int inode_unhashed(struct inode *inode)
+{
+ return hlist_bl_unhashed(&inode->i_hash);
+}
+
/*
* inode->i_mutex nesting subclasses for the lock validator:
*
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
index 961bc89..0d791ff 100644
--- a/include/linux/list_bl.h
+++ b/include/linux/list_bl.h
@@ -125,3 +125,21 @@ static inline void hlist_bl_del_init(struct hlist_bl_node *n)
pos = pos->next)
#endif
+
+/**
+ * hlist_bl_lock - lock a hash list
+ * @h: hash list head to lock
+ */
+static inline void hlist_bl_lock(struct hlist_bl_head *h)
+{
+ bit_spin_lock(0, (unsigned long *)h);
+}
+
+/**
+ * hlist_bl_unlock - unlock a hash list
+ * @h: hash list head to unlock
+ */
+static inline void hlist_bl_unlock(struct hlist_bl_head *h)
+{
+ __bit_spin_unlock(0, (unsigned long *)h);
+}
diff --git a/mm/shmem.c b/mm/shmem.c
index 7d0bc16..419de2c 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2146,7 +2146,7 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
if (*len < 3)
return 255;
- if (hlist_unhashed(&inode->i_hash)) {
+ if (inode_unhashed(inode)) {
/* Unfortunately insert_inode_hash is not idempotent,
* so as we hash inodes here rather than at creation
* time, we need a lock to ensure we only try
@@ -2154,7 +2154,7 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
*/
static DEFINE_SPINLOCK(lock);
spin_lock(&lock);
- if (hlist_unhashed(&inode->i_hash))
+ if (inode_unhashed(inode))
__insert_inode_hash(inode,
inode->i_ino + inode->i_generation);
spin_unlock(&lock);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 10/18] fs: add a per-superblock lock for the inode list
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (8 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 09/18] fs: Introduce per-bucket inode hash locks Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 11/18] fs: split locking of inode writeback and LRU lists Dave Chinner
` (8 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
To allow removal of the inode_lock, we first need to protect the
superblock inode list with its own lock instead of using the
inode_lock. Add a lock to the superblock to protect this list and
nest the new lock inside the inode_lock around the list operations
it needs to protect.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/drop_caches.c | 4 ++++
fs/fs-writeback.c | 4 ++++
fs/inode.c | 22 +++++++++++++++++++---
fs/notify/inode_mark.c | 3 +++
fs/quota/dquot.c | 6 ++++++
fs/super.c | 1 +
include/linux/fs.h | 1 +
7 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 10c8c5a..dfe8cb1 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -17,6 +17,7 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
struct inode *inode, *toput_inode = NULL;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
@@ -25,12 +26,15 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(toput_inode);
}
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 31d7f35..387385b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1025,6 +1025,7 @@ static void wait_sb_inodes(struct super_block *sb)
WARN_ON(!rwsem_is_locked(&sb->s_umount));
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
/*
* Data integrity sync. Must wait for all pages under writeback,
@@ -1044,6 +1045,7 @@ static void wait_sb_inodes(struct super_block *sb)
spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
/*
* We hold a reference to 'inode' so it couldn't have
@@ -1061,7 +1063,9 @@ static void wait_sb_inodes(struct super_block *sb)
cond_resched();
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
}
diff --git a/fs/inode.c b/fs/inode.c
index dd3270a..ab65f99 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -33,13 +33,18 @@
* i_ref
* inode hash lock protects:
* inode hash table, i_hash
+ * sb inode lock protects:
+ * s_inodes, i_sb_list
*
* Lock orders
* inode_lock
* inode hash bucket lock
* inode->i_lock
+ *
+ * inode_lock
+ * sb inode lock
+ * inode->i_lock
*/
-
/*
* This is needed for the following functions:
* - inode_has_buffers
@@ -474,7 +479,9 @@ static void dispose_list(struct list_head *head)
spin_lock(&inode_lock);
__remove_inode_hash(inode);
+ spin_lock(&inode->i_sb->s_inodes_lock);
list_del_init(&inode->i_sb_list);
+ spin_unlock(&inode->i_sb->s_inodes_lock);
spin_unlock(&inode_lock);
wake_up_inode(inode);
@@ -485,7 +492,8 @@ static void dispose_list(struct list_head *head)
/*
* Invalidate all inodes for a device.
*/
-static int invalidate_list(struct list_head *head, struct list_head *dispose)
+static int invalidate_list(struct super_block *sb, struct list_head *head,
+ struct list_head *dispose)
{
struct list_head *next;
int busy = 0;
@@ -502,6 +510,7 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
* shrink_icache_memory() away.
*/
cond_resched_lock(&inode_lock);
+ cond_resched_lock(&sb->s_inodes_lock);
next = next->next;
if (tmp == head)
@@ -540,8 +549,10 @@ int invalidate_inodes(struct super_block *sb)
down_write(&iprune_sem);
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
fsnotify_unmount_inodes(&sb->s_inodes);
- busy = invalidate_list(&sb->s_inodes, &throw_away);
+ busy = invalidate_list(sb, &sb->s_inodes, &throw_away);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
dispose_list(&throw_away);
@@ -747,7 +758,9 @@ static inline void
__inode_add_to_lists(struct super_block *sb, struct hlist_bl_head *b,
struct inode *inode)
{
+ spin_lock(&sb->s_inodes_lock);
list_add(&inode->i_sb_list, &sb->s_inodes);
+ spin_unlock(&sb->s_inodes_lock);
if (b) {
hlist_bl_lock(b);
hlist_bl_add_head(&inode->i_hash, b);
@@ -1387,7 +1400,10 @@ static void iput_final(struct inode *inode)
*/
inode_lru_list_del(inode);
+ spin_lock(&sb->s_inodes_lock);
list_del_init(&inode->i_sb_list);
+ spin_unlock(&sb->s_inodes_lock);
+
spin_unlock(&inode_lock);
evict(inode);
remove_inode_hash(inode);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 1a4c117..4ed0e43 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -242,6 +242,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
struct inode *need_iput_tmp;
+ struct super_block *sb = inode->i_sb;
/*
* We cannot iref() an inode in state I_FREEING,
@@ -290,6 +291,7 @@ void fsnotify_unmount_inodes(struct list_head *list)
* will be added since the umount has begun. Finally,
* iprune_mutex keeps shrink_icache_memory() away.
*/
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
if (need_iput_tmp)
@@ -303,5 +305,6 @@ void fsnotify_unmount_inodes(struct list_head *list)
iput(inode);
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
}
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 326df72..7ef5411 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -897,6 +897,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
#endif
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
continue;
@@ -912,6 +913,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
@@ -923,7 +925,9 @@ static void add_dquot_ref(struct super_block *sb, int type)
* keep the reference and iput it later. */
old_inode = inode;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
iput(old_inode);
@@ -1006,6 +1010,7 @@ static void remove_dquot_ref(struct super_block *sb, int type,
int reserved = 0;
spin_lock(&inode_lock);
+ spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
* We have to scan also I_NEW inodes because they can already
@@ -1019,6 +1024,7 @@ static void remove_dquot_ref(struct super_block *sb, int type,
remove_inode_dquot_ref(inode, type, tofree_head);
}
}
+ spin_unlock(&sb->s_inodes_lock);
spin_unlock(&inode_lock);
#ifdef CONFIG_QUOTA_DEBUG
if (reserved) {
diff --git a/fs/super.c b/fs/super.c
index 8819e3a..c5332e5 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -76,6 +76,7 @@ static struct super_block *alloc_super(struct file_system_type *type)
INIT_LIST_HEAD(&s->s_dentry_lru);
init_rwsem(&s->s_umount);
mutex_init(&s->s_lock);
+ spin_lock_init(&s->s_inodes_lock);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
/*
* The locking rules for s_lock are up to the
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 67dd926..767913a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1347,6 +1347,7 @@ struct super_block {
#endif
const struct xattr_handler **s_xattr;
+ spinlock_t s_inodes_lock; /* lock for s_inodes */
struct list_head s_inodes; /* all inodes */
struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */
#ifdef CONFIG_SMP
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 11/18] fs: split locking of inode writeback and LRU lists
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (9 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 10/18] fs: add a per-superblock lock for the inode list Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 3:26 ` Lin Ming
2010-10-13 13:18 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
` (7 subsequent siblings)
18 siblings, 2 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
Given that the inode LRU and IO lists are split apart, they do not
need to be protected by the same lock. So in preparation for removal
of the inode_lock, add new locks for them. The writeback lists are
only ever accessed in the context of a bdi, so add a per-BDI lock to
protect manipulations of these lists.
For the inode LRU, introduce a simple global lock to protect it.
While this could be made per-sb, it is unclear yet as to what is the
next step for optimising/parallelising reclaim of inodes. Rather
than optimise now, leave it as a global list and lock until further
analysis can be done.
Because there will now be a situation where the inode is on
different lists protected by different locks during the freeing of
the inode (i.e. not an atomic state transition), we need to ensure
that we set the I_FREEING state flag before we start removing inodes
from the IO and LRU lists. This ensures that if we race with other
threads during freeing, they will notice the I_FREEING flag is set
and be able to take appropriate action to avoid problems.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/fs-writeback.c | 51 +++++++++++++++++++++++++++++++++++++---
fs/inode.c | 54 ++++++++++++++++++++++++++++++++++++------
fs/internal.h | 5 ++++
include/linux/backing-dev.h | 1 +
mm/backing-dev.c | 18 ++++++++++++++
5 files changed, 117 insertions(+), 12 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 387385b..45046af 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -157,6 +157,18 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi)
}
/*
+ * Remove the inode from the writeback list it is on.
+ */
+void inode_wb_list_del(struct inode *inode)
+{
+ struct backing_dev_info *bdi = inode_to_bdi(inode);
+
+ spin_lock(&bdi->wb.b_lock);
+ list_del_init(&inode->i_wb_list);
+ spin_unlock(&bdi->wb.b_lock);
+}
+
+/*
* Redirty an inode: set its when-it-was dirtied timestamp and move it to the
* furthest end of its superblock's dirty-inode list.
*
@@ -169,6 +181,7 @@ static void redirty_tail(struct inode *inode)
{
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
+ assert_spin_locked(&wb->b_lock);
if (!list_empty(&wb->b_dirty)) {
struct inode *tail;
@@ -186,6 +199,7 @@ static void requeue_io(struct inode *inode)
{
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
+ assert_spin_locked(&wb->b_lock);
list_move(&inode->i_wb_list, &wb->b_more_io);
}
@@ -269,6 +283,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
*/
static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
{
+ assert_spin_locked(&wb->b_lock);
list_splice_init(&wb->b_more_io, &wb->b_io);
move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
}
@@ -311,6 +326,7 @@ static void inode_wait_for_writeback(struct inode *inode)
static int
writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
{
+ struct backing_dev_info *bdi = inode_to_bdi(inode);
struct address_space *mapping = inode->i_mapping;
unsigned dirty;
int ret;
@@ -330,7 +346,9 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completed a full scan of b_io.
*/
if (wbc->sync_mode != WB_SYNC_ALL) {
+ spin_lock(&bdi->wb.b_lock);
requeue_io(inode);
+ spin_unlock(&bdi->wb.b_lock);
return 0;
}
@@ -385,6 +403,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* sometimes bales out without doing anything.
*/
inode->i_state |= I_DIRTY_PAGES;
+ spin_lock(&bdi->wb.b_lock);
if (wbc->nr_to_write <= 0) {
/*
* slice used up: queue for next turn
@@ -400,6 +419,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
*/
redirty_tail(inode);
}
+ spin_unlock(&bdi->wb.b_lock);
} else if (inode->i_state & I_DIRTY) {
/*
* Filesystems can dirty the inode during writeback
@@ -407,10 +427,12 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* submission or metadata updates after data IO
* completion.
*/
+ spin_lock(&bdi->wb.b_lock);
redirty_tail(inode);
+ spin_unlock(&bdi->wb.b_lock);
} else {
/* The inode is clean */
- list_del_init(&inode->i_wb_list);
+ inode_wb_list_del(inode);
inode_lru_list_add(inode);
}
}
@@ -457,6 +479,7 @@ static bool pin_sb_for_writeback(struct super_block *sb)
static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
struct writeback_control *wbc, bool only_this_sb)
{
+ assert_spin_locked(&wb->b_lock);
while (!list_empty(&wb->b_io)) {
long pages_skipped;
struct inode *inode = list_entry(wb->b_io.prev,
@@ -472,7 +495,6 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
redirty_tail(inode);
continue;
}
-
/*
* The inode belongs to a different superblock.
* Bounce back to the caller to unpin this and
@@ -481,7 +503,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
return 0;
}
- if (inode->i_state & (I_NEW | I_WILL_FREE)) {
+ /*
+ * We can see I_FREEING here when the inod isin the process of
+ * being reclaimed. In that case the freer is waiting on the
+ * wb->b_lock that we currently hold to remove the inode from
+ * the writeback list. So we don't spin on it here, requeue it
+ * and move on to the next inode, which will allow the other
+ * thread to free the inode when we drop the lock.
+ */
+ if (inode->i_state & (I_NEW | I_WILL_FREE | I_FREEING)) {
requeue_io(inode);
continue;
}
@@ -492,10 +522,11 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
if (inode_dirtied_after(inode, wbc->wb_start))
return 1;
- BUG_ON(inode->i_state & I_FREEING);
spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
+ spin_unlock(&wb->b_lock);
+
pages_skipped = wbc->pages_skipped;
writeback_single_inode(inode, wbc);
if (wbc->pages_skipped != pages_skipped) {
@@ -503,12 +534,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* writeback is not making progress due to locked
* buffers. Skip this inode for now.
*/
+ spin_lock(&wb->b_lock);
redirty_tail(inode);
+ spin_unlock(&wb->b_lock);
}
spin_unlock(&inode_lock);
iput(inode);
cond_resched();
spin_lock(&inode_lock);
+ spin_lock(&wb->b_lock);
if (wbc->nr_to_write <= 0) {
wbc->more_io = 1;
return 1;
@@ -528,6 +562,8 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
if (!wbc->wb_start)
wbc->wb_start = jiffies; /* livelock avoidance */
spin_lock(&inode_lock);
+ spin_lock(&wb->b_lock);
+
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
@@ -546,6 +582,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
if (ret)
break;
}
+ spin_unlock(&wb->b_lock);
spin_unlock(&inode_lock);
/* Leave any unwritten inodes on b_io */
}
@@ -556,9 +593,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
WARN_ON(!rwsem_is_locked(&sb->s_umount));
spin_lock(&inode_lock);
+ spin_lock(&wb->b_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
writeback_sb_inodes(sb, wb, wbc, true);
+ spin_unlock(&wb->b_lock);
spin_unlock(&inode_lock);
}
@@ -671,8 +710,10 @@ static long wb_writeback(struct bdi_writeback *wb,
*/
spin_lock(&inode_lock);
if (!list_empty(&wb->b_more_io)) {
+ spin_lock(&wb->b_lock);
inode = list_entry(wb->b_more_io.prev,
struct inode, i_wb_list);
+ spin_unlock(&wb->b_lock);
trace_wbc_writeback_wait(&wbc, wb->bdi);
inode_wait_for_writeback(inode);
}
@@ -985,8 +1026,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
wakeup_bdi = true;
}
+ spin_lock(&bdi->wb.b_lock);
inode->dirtied_when = jiffies;
list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
+ spin_unlock(&bdi->wb.b_lock);
}
}
out:
diff --git a/fs/inode.c b/fs/inode.c
index ab65f99..a9ba18a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -26,6 +26,8 @@
#include <linux/posix_acl.h>
#include <linux/bit_spinlock.h>
+#include "internal.h"
+
/*
* Locking rules.
*
@@ -35,6 +37,10 @@
* inode hash table, i_hash
* sb inode lock protects:
* s_inodes, i_sb_list
+ * bdi writeback lock protects:
+ * b_io, b_more_io, b_dirty, i_io
+ * inode_lru_lock protects:
+ * inode_lru, i_lru
*
* Lock orders
* inode_lock
@@ -43,7 +49,9 @@
*
* inode_lock
* sb inode lock
- * inode->i_lock
+ * inode_lru_lock
+ * wb->b_lock
+ * inode->i_lock
*/
/*
* This is needed for the following functions:
@@ -93,6 +101,7 @@ static struct hlist_bl_head *inode_hashtable __read_mostly;
* allowing for low-overhead inode sync() operations.
*/
static LIST_HEAD(inode_lru);
+static DEFINE_SPINLOCK(inode_lru_lock);
/*
* A simple spinlock to protect the list manipulations.
@@ -353,20 +362,28 @@ void iref(struct inode *inode)
}
EXPORT_SYMBOL_GPL(iref);
+/*
+ * check against I_FREEING as inode writeback completion could race with
+ * setting the I_FREEING and removing the inode from the LRU.
+ */
void inode_lru_list_add(struct inode *inode)
{
- if (list_empty(&inode->i_lru)) {
+ spin_lock(&inode_lru_lock);
+ if (list_empty(&inode->i_lru) && !(inode->i_state & I_FREEING)) {
list_add(&inode->i_lru, &inode_lru);
percpu_counter_inc(&nr_inodes_unused);
}
+ spin_unlock(&inode_lru_lock);
}
void inode_lru_list_del(struct inode *inode)
{
+ spin_lock(&inode_lru_lock);
if (!list_empty(&inode->i_lru)) {
list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
}
+ spin_unlock(&inode_lru_lock);
}
static unsigned long hash(struct super_block *sb, unsigned long hashval)
@@ -524,8 +541,18 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
spin_unlock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+
+ /*
+ * move the inode off the IO lists and LRU once
+ * I_FREEING is set so that it won't get moved back on
+ * there if it is dirty.
+ */
+ inode_wb_list_del(inode);
+
+ spin_lock(&inode_lru_lock);
list_move(&inode->i_lru, dispose);
percpu_counter_dec(&nr_inodes_unused);
+ spin_unlock(&inode_lru_lock);
continue;
}
spin_unlock(&inode->i_lock);
@@ -599,6 +626,7 @@ static void prune_icache(int nr_to_scan)
down_read(&iprune_sem);
spin_lock(&inode_lock);
+ spin_lock(&inode_lru_lock);
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;
@@ -629,12 +657,14 @@ static void prune_icache(int nr_to_scan)
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
inode->i_ref++;
spin_unlock(&inode->i_lock);
+ spin_unlock(&inode_lru_lock);
spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
spin_lock(&inode_lock);
+ spin_lock(&inode_lru_lock);
/*
* if we can't reclaim this inode immediately, give it
@@ -647,16 +677,24 @@ static void prune_icache(int nr_to_scan)
}
} else
spin_unlock(&inode->i_lock);
- list_move(&inode->i_lru, &freeable);
- list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+
+ /*
+ * move the inode off the io lists and lru once
+ * i_freeing is set so that it won't get moved back on
+ * there if it is dirty.
+ */
+ inode_wb_list_del(inode);
+
+ list_move(&inode->i_lru, &freeable);
percpu_counter_dec(&nr_inodes_unused);
}
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
__count_vm_events(PGINODESTEAL, reap);
+ spin_unlock(&inode_lru_lock);
spin_unlock(&inode_lock);
dispose_list(&freeable);
@@ -1389,15 +1427,15 @@ static void iput_final(struct inode *inode)
inode->i_state &= ~I_WILL_FREE;
__remove_inode_hash(inode);
}
- list_del_init(&inode->i_wb_list);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
/*
- * After we delete the inode from the LRU here, we avoid moving dirty
- * inodes back onto the LRU now because I_FREEING is set and hence
- * writeback_single_inode() won't move the inode around.
+ * After we delete the inode from the LRU and IO lists here, we avoid
+ * moving dirty inodes back onto the LRU now because I_FREEING is set
+ * and hence writeback_single_inode() won't move the inode around.
*/
+ inode_wb_list_del(inode);
inode_lru_list_del(inode);
spin_lock(&sb->s_inodes_lock);
diff --git a/fs/internal.h b/fs/internal.h
index ece3565..f8825ae 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -107,3 +107,8 @@ extern void release_open_intent(struct nameidata *);
*/
extern void inode_lru_list_add(struct inode *inode);
extern void inode_lru_list_del(struct inode *inode);
+
+/*
+ * fs-writeback.c
+ */
+extern void inode_wb_list_del(struct inode *inode);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 35b0074..970056a 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -57,6 +57,7 @@ struct bdi_writeback {
struct list_head b_dirty; /* dirty inodes */
struct list_head b_io; /* parked for writeback */
struct list_head b_more_io; /* parked for more writeback */
+ spinlock_t b_lock; /* writeback lists lock */
};
struct backing_dev_info {
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 15d5097..2cdb7a8 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -74,12 +74,14 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
nr_wb = nr_dirty = nr_io = nr_more_io = 0;
spin_lock(&inode_lock);
+ spin_lock(&wb->b_lock);
list_for_each_entry(inode, &wb->b_dirty, i_wb_list)
nr_dirty++;
list_for_each_entry(inode, &wb->b_io, i_wb_list)
nr_io++;
list_for_each_entry(inode, &wb->b_more_io, i_wb_list)
nr_more_io++;
+ spin_unlock(&wb->b_lock);
spin_unlock(&inode_lock);
global_dirty_limits(&background_thresh, &dirty_thresh);
@@ -634,6 +636,7 @@ static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi)
INIT_LIST_HEAD(&wb->b_dirty);
INIT_LIST_HEAD(&wb->b_io);
INIT_LIST_HEAD(&wb->b_more_io);
+ spin_lock_init(&wb->b_lock);
setup_timer(&wb->wakeup_timer, wakeup_timer_fn, (unsigned long)bdi);
}
@@ -671,6 +674,18 @@ err:
}
EXPORT_SYMBOL(bdi_init);
+static void bdi_lock_two(struct backing_dev_info *bdi1,
+ struct backing_dev_info *bdi2)
+{
+ if (bdi1 < bdi2) {
+ spin_lock(&bdi1->wb.b_lock);
+ spin_lock_nested(&bdi2->wb.b_lock, 1);
+ } else {
+ spin_lock(&bdi2->wb.b_lock);
+ spin_lock_nested(&bdi1->wb.b_lock, 1);
+ }
+}
+
void bdi_destroy(struct backing_dev_info *bdi)
{
int i;
@@ -683,9 +698,12 @@ void bdi_destroy(struct backing_dev_info *bdi)
struct bdi_writeback *dst = &default_backing_dev_info.wb;
spin_lock(&inode_lock);
+ bdi_lock_two(bdi, &default_backing_dev_info);
list_splice(&bdi->wb.b_dirty, &dst->b_dirty);
list_splice(&bdi->wb.b_io, &dst->b_io);
list_splice(&bdi->wb.b_more_io, &dst->b_more_io);
+ spin_unlock(&bdi->wb.b_lock);
+ spin_unlock(&dst->b_lock);
spin_unlock(&inode_lock);
}
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (10 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 11/18] fs: split locking of inode writeback and LRU lists Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 13:27 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 13/18] fs: introduce a per-cpu last_ino allocator Dave Chinner
` (6 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
We currently protect the per-inode state flags with the inode_lock.
Using a global lock to protect per-object state is overkill when we
coul duse a per-inode lock to protect the state. Use the
inode->i_lock for this, and wrap all the state changes and checks
with the inode->i_lock.
Based on work originally written by Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/drop_caches.c | 9 +++--
fs/fs-writeback.c | 45 ++++++++++++++++++-----
fs/inode.c | 93 ++++++++++++++++++++++++++++++++++-------------
fs/nilfs2/gcdat.c | 1 +
fs/notify/inode_mark.c | 6 ++-
fs/quota/dquot.c | 12 +++---
6 files changed, 118 insertions(+), 48 deletions(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index dfe8cb1..f958dd8 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -19,11 +19,12 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
- continue;
- if (inode->i_mapping->nrpages == 0)
- continue;
spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ (inode->i_mapping->nrpages == 0)) {
+ spin_unlock(&inode->i_lock);
+ continue;
+ }
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 45046af..9b25bc1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -304,10 +304,12 @@ static void inode_wait_for_writeback(struct inode *inode)
wait_queue_head_t *wqh;
wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
- while (inode->i_state & I_SYNC) {
+ while (inode->i_state & I_SYNC) {
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
}
}
@@ -331,6 +333,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
unsigned dirty;
int ret;
+ spin_lock(&inode->i_lock);
if (!inode->i_ref)
WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
else
@@ -346,6 +349,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* completed a full scan of b_io.
*/
if (wbc->sync_mode != WB_SYNC_ALL) {
+ spin_unlock(&inode->i_lock);
spin_lock(&bdi->wb.b_lock);
requeue_io(inode);
spin_unlock(&bdi->wb.b_lock);
@@ -363,6 +367,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
/* Set I_SYNC, reset I_DIRTY_PAGES */
inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY_PAGES;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
ret = do_writepages(mapping, wbc);
@@ -384,8 +389,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* write_inode()
*/
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
@@ -395,6 +402,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
}
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) {
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
@@ -403,6 +411,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* sometimes bales out without doing anything.
*/
inode->i_state |= I_DIRTY_PAGES;
+ spin_unlock(&inode->i_lock);
spin_lock(&bdi->wb.b_lock);
if (wbc->nr_to_write <= 0) {
/*
@@ -427,14 +436,19 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* submission or metadata updates after data IO
* completion.
*/
+ spin_unlock(&inode->i_lock);
spin_lock(&bdi->wb.b_lock);
redirty_tail(inode);
spin_unlock(&bdi->wb.b_lock);
} else {
/* The inode is clean */
+ spin_unlock(&inode->i_lock);
inode_wb_list_del(inode);
inode_lru_list_add(inode);
}
+ } else {
+ /* freer will clean up */
+ spin_unlock(&inode->i_lock);
}
inode_sync_complete(inode);
return ret;
@@ -511,7 +525,9 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* and move on to the next inode, which will allow the other
* thread to free the inode when we drop the lock.
*/
+ spin_lock(&inode->i_lock);
if (inode->i_state & (I_NEW | I_WILL_FREE | I_FREEING)) {
+ spin_unlock(&inode->i_lock);
requeue_io(inode);
continue;
}
@@ -519,10 +535,11 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
* Was this inode dirtied after sync_sb_inodes was called?
* This keeps sync from extra jobs and livelock.
*/
- if (inode_dirtied_after(inode, wbc->wb_start))
+ if (inode_dirtied_after(inode, wbc->wb_start)) {
+ spin_unlock(&inode->i_lock);
return 1;
+ }
- spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&wb->b_lock);
@@ -713,9 +730,11 @@ static long wb_writeback(struct bdi_writeback *wb,
spin_lock(&wb->b_lock);
inode = list_entry(wb->b_more_io.prev,
struct inode, i_wb_list);
+ spin_lock(&inode->i_lock);
spin_unlock(&wb->b_lock);
trace_wbc_writeback_wait(&wbc, wb->bdi);
inode_wait_for_writeback(inode);
+ spin_unlock(&inode->i_lock);
}
spin_unlock(&inode_lock);
}
@@ -981,6 +1000,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
block_dump___mark_inode_dirty(inode);
spin_lock(&inode_lock);
+ spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
@@ -992,7 +1012,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
* superblock list, based upon its state.
*/
if (inode->i_state & I_SYNC)
- goto out;
+ goto out_unlock;
/*
* Only add valid (hashed) inodes to the superblock's
@@ -1000,10 +1020,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
*/
if (!S_ISBLK(inode->i_mode)) {
if (inode_unhashed(inode))
- goto out;
+ goto out_unlock;
}
if (inode->i_state & I_FREEING)
- goto out;
+ goto out_unlock;
/*
* If the inode was already on b_dirty/b_io/b_more_io, don't
@@ -1026,12 +1046,16 @@ void __mark_inode_dirty(struct inode *inode, int flags)
wakeup_bdi = true;
}
+ spin_unlock(&inode->i_lock);
spin_lock(&bdi->wb.b_lock);
inode->dirtied_when = jiffies;
list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
spin_unlock(&bdi->wb.b_lock);
+ goto out;
}
}
+out_unlock:
+ spin_unlock(&inode->i_lock);
out:
spin_unlock(&inode_lock);
@@ -1080,12 +1104,13 @@ static void wait_sb_inodes(struct super_block *sb)
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping;
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
- continue;
+ spin_lock(&inode->i_lock);
mapping = inode->i_mapping;
- if (mapping->nrpages == 0)
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ mapping->nrpages == 0) {
+ spin_unlock(&inode->i_lock);
continue;
- spin_lock(&inode->i_lock);
+ }
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
diff --git a/fs/inode.c b/fs/inode.c
index a9ba18a..3094356 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -32,7 +32,7 @@
* Locking rules.
*
* inode->i_lock protects:
- * i_ref
+ * i_ref i_state
* inode hash lock protects:
* inode hash table, i_hash
* sb inode lock protects:
@@ -168,7 +168,7 @@ int proc_nr_inodes(ctl_table *table, int write,
static void wake_up_inode(struct inode *inode)
{
/*
- * Prevent speculative execution through spin_unlock(&inode_lock);
+ * Prevent speculative execution through spin_unlock(&inode->i_lock);
*/
smp_mb();
wake_up_bit(&inode->i_state, __I_NEW);
@@ -456,7 +456,9 @@ void end_writeback(struct inode *inode)
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
inode_sync_wait(inode);
+ spin_lock(&inode->i_lock);
inode->i_state = I_FREEING | I_CLEAR;
+ spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL(end_writeback);
@@ -533,14 +535,16 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
if (tmp == head)
break;
inode = list_entry(tmp, struct inode, i_sb_list);
- if (inode->i_state & I_NEW)
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & I_NEW) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
invalidate_inode_buffers(inode);
- spin_lock(&inode->i_lock);
if (!inode->i_ref) {
- spin_unlock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ spin_unlock(&inode->i_lock);
/*
* move the inode off the IO lists and LRU once
@@ -591,6 +595,7 @@ EXPORT_SYMBOL(invalidate_inodes);
static int can_unuse(struct inode *inode)
{
+ assert_spin_locked(&inode->i_lock);
if (inode->i_state)
return 0;
if (inode_has_buffers(inode))
@@ -649,9 +654,9 @@ static void prune_icache(int nr_to_scan)
/* recently referenced inodes get one more pass */
if (inode->i_state & I_REFERENCED) {
+ inode->i_state &= ~I_REFERENCED;
spin_unlock(&inode->i_lock);
list_move(&inode->i_lru, &inode_lru);
- inode->i_state &= ~I_REFERENCED;
continue;
}
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
@@ -665,6 +670,7 @@ static void prune_icache(int nr_to_scan)
iput(inode);
spin_lock(&inode_lock);
spin_lock(&inode_lru_lock);
+ spin_lock(&inode->i_lock);
/*
* if we can't reclaim this inode immediately, give it
@@ -673,12 +679,14 @@ static void prune_icache(int nr_to_scan)
*/
if (!can_unuse(inode)) {
list_move(&inode->i_lru, &inode_lru);
+ spin_unlock(&inode->i_lock);
continue;
}
- } else
- spin_unlock(&inode->i_lock);
+ }
+
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ spin_unlock(&inode->i_lock);
/*
* move the inode off the io lists and lru once
@@ -732,7 +740,7 @@ static struct shrinker icache_shrinker = {
static void __wait_on_freeing_inode(struct inode *inode);
/*
- * Called with the inode lock held.
+ * Called with the inode->i_lock held.
* NOTE: we are not increasing the inode-refcount, you must take a reference
* by hand after calling find_inode now! This simplifies iunique and won't
* add any additional branch in the common code.
@@ -750,8 +758,11 @@ repeat:
hlist_bl_for_each_entry(inode, node, b, i_hash) {
if (inode->i_sb != sb)
continue;
- if (!test(inode, data))
+ spin_lock(&inode->i_lock);
+ if (!test(inode, data)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
hlist_bl_unlock(b);
__wait_on_freeing_inode(inode);
@@ -781,6 +792,7 @@ repeat:
continue;
if (inode->i_sb != sb)
continue;
+ spin_lock(&inode->i_lock);
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
hlist_bl_unlock(b);
__wait_on_freeing_inode(inode);
@@ -855,9 +867,14 @@ struct inode *new_inode(struct super_block *sb)
inode = alloc_inode(sb);
if (inode) {
spin_lock(&inode_lock);
- __inode_add_to_lists(sb, NULL, inode);
+
+ /*
+ * set the inode state before we make the inode accessible to
+ * the outside world.
+ */
inode->i_ino = ++last_ino;
inode->i_state = 0;
+ __inode_add_to_lists(sb, NULL, inode);
spin_unlock(&inode_lock);
}
return inode;
@@ -924,8 +941,12 @@ static struct inode *get_new_inode(struct super_block *sb,
if (set(inode, data))
goto set_failed;
- __inode_add_to_lists(sb, b, inode);
+ /*
+ * Set the inode state before we make the inode
+ * visible to the outside world.
+ */
inode->i_state = I_NEW;
+ __inode_add_to_lists(sb, b, inode);
spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
@@ -939,7 +960,6 @@ static struct inode *get_new_inode(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
@@ -972,9 +992,13 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
/* We released the lock, so.. */
old = find_inode_fast(sb, b, ino);
if (!old) {
+ /*
+ * Set the inode state before we make the inode
+ * visible to the outside world.
+ */
inode->i_ino = ino;
- __inode_add_to_lists(sb, b, inode);
inode->i_state = I_NEW;
+ __inode_add_to_lists(sb, b, inode);
spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
@@ -988,7 +1012,6 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
spin_unlock(&inode_lock);
@@ -1089,7 +1112,6 @@ static struct inode *ifind(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode(sb, b, test, data);
if (inode) {
- spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
@@ -1125,7 +1147,6 @@ static struct inode *ifind_fast(struct super_block *sb,
spin_lock(&inode_lock);
inode = find_inode_fast(sb, b, ino);
if (inode) {
- spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
@@ -1302,8 +1323,11 @@ int insert_inode_locked(struct inode *inode)
continue;
if (old->i_sb != sb)
continue;
- if (old->i_state & (I_FREEING|I_WILL_FREE))
+ spin_lock(&old->i_lock);
+ if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+ spin_unlock(&old->i_lock);
continue;
+ }
break;
}
if (likely(!node)) {
@@ -1312,7 +1336,6 @@ int insert_inode_locked(struct inode *inode)
spin_unlock(&inode_lock);
return 0;
}
- spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
hlist_bl_unlock(b);
@@ -1333,6 +1356,10 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
struct super_block *sb = inode->i_sb;
struct hlist_bl_head *b = inode_hashtable + hash(sb, hashval);
+ /*
+ * Nobody else can see the new inode yet, so it is safe to set flags
+ * without locking here.
+ */
inode->i_state |= I_NEW;
while (1) {
@@ -1346,8 +1373,11 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
continue;
if (!test(old, data))
continue;
- if (old->i_state & (I_FREEING|I_WILL_FREE))
+ spin_lock(&old->i_lock);
+ if (old->i_state & (I_FREEING|I_WILL_FREE)) {
+ spin_unlock(&old->i_lock);
continue;
+ }
break;
}
if (likely(!node)) {
@@ -1356,7 +1386,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
spin_unlock(&inode_lock);
return 0;
}
- spin_lock(&old->i_lock);
old->i_ref++;
spin_unlock(&old->i_lock);
hlist_bl_unlock(b);
@@ -1405,6 +1434,8 @@ static void iput_final(struct inode *inode)
const struct super_operations *op = inode->i_sb->s_op;
int drop;
+ assert_spin_locked(&inode->i_lock);
+
if (op && op->drop_inode)
drop = op->drop_inode(inode);
else
@@ -1413,22 +1444,30 @@ static void iput_final(struct inode *inode)
if (!drop) {
if (sb->s_flags & MS_ACTIVE) {
inode->i_state |= I_REFERENCED;
- if (!(inode->i_state & (I_DIRTY|I_SYNC)))
+ if (!(inode->i_state & (I_DIRTY|I_SYNC)) &&
+ list_empty(&inode->i_lru)) {
+ spin_unlock(&inode->i_lock);
inode_lru_list_add(inode);
+ return;
+ }
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
return;
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_WILL_FREE;
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
write_inode_now(inode, 1);
spin_lock(&inode_lock);
+ __remove_inode_hash(inode);
+ spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
- __remove_inode_hash(inode);
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_FREEING;
+ spin_unlock(&inode->i_lock);
/*
* After we delete the inode from the LRU and IO lists here, we avoid
@@ -1462,12 +1501,11 @@ static void iput_final(struct inode *inode)
void iput(struct inode *inode)
{
if (inode) {
- BUG_ON(inode->i_state & I_CLEAR);
-
spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
+ BUG_ON(inode->i_state & I_CLEAR);
+
if (--inode->i_ref == 0) {
- spin_unlock(&inode->i_lock);
iput_final(inode);
return;
}
@@ -1653,6 +1691,8 @@ EXPORT_SYMBOL(inode_wait);
* wake_up_inode() after removing from the hash list will DTRT.
*
* This is called with inode_lock held.
+ *
+ * Called with i_lock held and returns with it dropped.
*/
static void __wait_on_freeing_inode(struct inode *inode)
{
@@ -1660,6 +1700,7 @@ static void __wait_on_freeing_inode(struct inode *inode)
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&inode->i_lock);
spin_unlock(&inode_lock);
schedule();
finish_wait(wq, &wait.wait);
diff --git a/fs/nilfs2/gcdat.c b/fs/nilfs2/gcdat.c
index 84a45d1..c51f0e8 100644
--- a/fs/nilfs2/gcdat.c
+++ b/fs/nilfs2/gcdat.c
@@ -27,6 +27,7 @@
#include "page.h"
#include "mdt.h"
+/* XXX: what protects i_state? */
int nilfs_init_gcdat_inode(struct the_nilfs *nilfs)
{
struct inode *dat = nilfs->ns_dat, *gcdat = nilfs->ns_gc_dat;
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 4ed0e43..203146b 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -249,8 +249,11 @@ void fsnotify_unmount_inodes(struct list_head *list)
* I_WILL_FREE, or I_NEW which is fine because by that point
* the inode cannot have any associated watches.
*/
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ spin_lock(&inode->i_lock);
+ if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
/*
* If i_ref is zero, the inode cannot have any watches and
@@ -258,7 +261,6 @@ void fsnotify_unmount_inodes(struct list_head *list)
* evict all inodes with zero i_ref from icache which is
* unnecessarily violent and may in fact be illegal to do.
*/
- spin_lock(&inode->i_lock);
if (!inode->i_ref) {
spin_unlock(&inode->i_lock);
continue;
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 7ef5411..b02a3e1 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -899,18 +899,18 @@ static void add_dquot_ref(struct super_block *sb, int type)
spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ spin_lock(&inode->i_lock);
+ if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
+ !atomic_read(&inode->i_writecount) ||
+ !dqinit_needed(inode, type)) {
+ spin_unlock(&inode->i_lock);
continue;
+ }
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
- if (!atomic_read(&inode->i_writecount))
- continue;
- if (!dqinit_needed(inode, type))
- continue;
- spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 13/18] fs: introduce a per-cpu last_ino allocator
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (11 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 14/18] fs: Make iunique independent of inode_lock Dave Chinner
` (5 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Eric Dumazet <eric.dumazet@gmail.com>
new_inode() dirties a contended cache line to get increasing
inode numbers. This limits performance on workloads that cause
significant parallel inode allocation.
Solve this problem by using a per_cpu variable fed by the shared
last_ino in batches of 1024 allocations. This reduces contention on
the shared last_ino, and give same spreading ino numbers than before
(i.e. same wraparound after 2^32 allocations).
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/inode.c | 45 ++++++++++++++++++++++++++++++++++++++-------
1 files changed, 38 insertions(+), 7 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 3094356..e65a01d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -840,6 +840,43 @@ void inode_add_to_lists(struct super_block *sb, struct inode *inode)
}
EXPORT_SYMBOL_GPL(inode_add_to_lists);
+/*
+ * Each cpu owns a range of LAST_INO_BATCH numbers.
+ * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
+ * to renew the exhausted range.
+ *
+ * This does not significantly increase overflow rate because every CPU can
+ * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
+ * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
+ * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
+ * overflow rate by 2x, which does not seem too significant.
+ *
+ * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
+ * error if st_ino won't fit in target struct field. Use 32bit counter
+ * here to attempt to avoid that.
+ */
+#define LAST_INO_BATCH 1024
+static DEFINE_PER_CPU(unsigned int, last_ino);
+
+static unsigned int get_next_ino(void)
+{
+ unsigned int *p = &get_cpu_var(last_ino);
+ unsigned int res = *p;
+
+#ifdef CONFIG_SMP
+ if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
+ static atomic_t shared_last_ino;
+ int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
+
+ res = next - LAST_INO_BATCH;
+ }
+#endif
+
+ *p = ++res;
+ put_cpu_var(last_ino);
+ return res;
+}
+
/**
* new_inode - obtain an inode
* @sb: superblock
@@ -854,12 +891,6 @@ EXPORT_SYMBOL_GPL(inode_add_to_lists);
*/
struct inode *new_inode(struct super_block *sb)
{
- /*
- * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
- * error if st_ino won't fit in target struct field. Use 32bit counter
- * here to attempt to avoid that.
- */
- static unsigned int last_ino;
struct inode *inode;
spin_lock_prefetch(&inode_lock);
@@ -872,7 +903,7 @@ struct inode *new_inode(struct super_block *sb)
* set the inode state before we make the inode accessible to
* the outside world.
*/
- inode->i_ino = ++last_ino;
+ inode->i_ino = get_next_ino();
inode->i_state = 0;
__inode_add_to_lists(sb, NULL, inode);
spin_unlock(&inode_lock);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 14/18] fs: Make iunique independent of inode_lock
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (12 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 13/18] fs: introduce a per-cpu last_ino allocator Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 0:15 ` [PATCH 15/18] fs: icache remove inode_lock Dave Chinner
` (4 subsequent siblings)
18 siblings, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Nick Piggin <npiggin@suse.de>
Before removing the inode_lock, the iunique counter needs to be made
independent of the inode_lock. Add a new lock to protect the iunique
counter and nest it inside the inode_lock to provide the same
protection that the inode_lock currently provides.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/inode.c | 35 ++++++++++++++++++++++++++++-------
1 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index e65a01d..434a49b 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1053,6 +1053,30 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
return inode;
}
+/*
+ * search the inode cache for a matching inode number.
+ * If we find one, then the inode number we are trying to
+ * allocate is not unique and so we should not use it.
+ *
+ * Returns 1 if the inode number is unique, 0 if it is not.
+ */
+static int test_inode_iunique(struct super_block * sb, unsigned long ino)
+{
+ struct hlist_bl_head *b = inode_hashtable + hash(sb, ino);
+ struct hlist_bl_node *node;
+ struct inode *inode;
+
+ hlist_bl_lock(b);
+ hlist_bl_for_each_entry(inode, node, b, i_hash) {
+ if (inode->i_ino == ino && inode->i_sb == sb) {
+ hlist_bl_unlock(b);
+ return 0;
+ }
+ }
+ hlist_bl_unlock(b);
+ return 1;
+}
+
/**
* iunique - get a unique inode number
* @sb: superblock
@@ -1074,20 +1098,17 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
* error if st_ino won't fit in target struct field. Use 32bit counter
* here to attempt to avoid that.
*/
+ static DEFINE_SPINLOCK(iunique_lock);
static unsigned int counter;
- struct inode *inode;
- struct hlist_bl_head *b;
ino_t res;
- spin_lock(&inode_lock);
+ spin_lock(&iunique_lock);
do {
if (counter <= max_reserved)
counter = max_reserved + 1;
res = counter++;
- b = inode_hashtable + hash(sb, res);
- inode = find_inode_fast(sb, b, res);
- } while (inode != NULL);
- spin_unlock(&inode_lock);
+ } while (!test_inode_iunique(sb, res));
+ spin_unlock(&iunique_lock);
return res;
}
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 15/18] fs: icache remove inode_lock
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (13 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 14/18] fs: Make iunique independent of inode_lock Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 2:09 ` Dave Chinner
2010-10-13 13:42 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
` (3 subsequent siblings)
18 siblings, 2 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
All the functionality that the inode_lock protected has now been
wrapped up in new independent locks and/or functionality. Hence the
inode_lock does not serve a purpose any longer and hence can now be
removed.
Based on work originally done by Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
Documentation/filesystems/Locking | 2 +-
Documentation/filesystems/porting | 10 +++-
Documentation/filesystems/vfs.txt | 2 +-
fs/buffer.c | 2 +-
fs/drop_caches.c | 4 --
fs/fs-writeback.c | 45 +++-------------
fs/inode.c | 101 +++++--------------------------------
fs/logfs/inode.c | 2 +-
fs/notify/inode_mark.c | 11 ++---
fs/notify/mark.c | 1 -
fs/notify/vfsmount_mark.c | 1 -
fs/ntfs/inode.c | 4 +-
fs/ocfs2/inode.c | 2 +-
fs/quota/dquot.c | 12 +---
include/linux/fs.h | 2 +-
include/linux/writeback.h | 2 -
mm/backing-dev.c | 4 --
mm/filemap.c | 6 +-
mm/rmap.c | 6 +-
19 files changed, 51 insertions(+), 168 deletions(-)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 2db4283..e92dad2 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -114,7 +114,7 @@ alloc_inode:
destroy_inode:
dirty_inode: (must not sleep)
write_inode:
-drop_inode: !!!inode_lock!!!
+drop_inode: !!!i_lock, sb_inode_list_lock!!!
evict_inode:
put_super: write
write_super: read
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index b12c895..ab07213 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -299,7 +299,7 @@ be used instead. It gets called whenever the inode is evicted, whether it has
remaining links or not. Caller does *not* evict the pagecache or inode-associated
metadata buffers; getting rid of those is responsibility of method, as it had
been for ->delete_inode().
- ->drop_inode() returns int now; it's called on final iput() with inode_lock
+ ->drop_inode() returns int now; it's called on final iput() with i_lock
held and it returns true if filesystems wants the inode to be dropped. As before,
generic_drop_inode() is still the default and it's been updated appropriately.
generic_delete_inode() is also alive and it consists simply of return 1. Note that
@@ -318,3 +318,11 @@ if it's zero is not *and* *never* *had* *been* enough. Final unlink() and iput(
may happen while the inode is in the middle of ->write_inode(); e.g. if you blindly
free the on-disk inode, you may end up doing that while ->write_inode() is writing
to it.
+
+
+[mandatory]
+ inode_lock is gone, replaced by fine grained locks. See fs/inode.c
+for details of what locks to replace inode_lock with in order to protect
+particular things. Most of the time, a filesystem only needs ->i_lock, which
+protects *all* the inode state and its membership on lists that was
+previously protected with inode_lock.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index ed7e5ef..405beb2 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -246,7 +246,7 @@ or bottom half).
should be synchronous or not, not all filesystems check this flag.
drop_inode: called when the last access to the inode is dropped,
- with the inode_lock spinlock held.
+ with the i_lock and sb_inode_list_lock spinlock held.
This method should be either NULL (normal UNIX filesystem
semantics) or "generic_delete_inode" (for filesystems that do not
diff --git a/fs/buffer.c b/fs/buffer.c
index 3e7dca2..66f7afd 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1145,7 +1145,7 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
* inode list.
*
* mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock,
- * mapping->tree_lock and the global inode_lock.
+ * and mapping->tree_lock.
*/
void mark_buffer_dirty(struct buffer_head *bh)
{
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index f958dd8..bd39f65 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -16,7 +16,6 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
{
struct inode *inode, *toput_inode = NULL;
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
@@ -28,15 +27,12 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
iput(toput_inode);
toput_inode = inode;
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
}
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
iput(toput_inode);
}
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 9b25bc1..aa46d73 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -206,7 +206,7 @@ static void requeue_io(struct inode *inode)
static void inode_sync_complete(struct inode *inode)
{
/*
- * Prevent speculative execution through spin_unlock(&inode_lock);
+ * Prevent speculative execution through spin_unlock(&inode->i_lock);
*/
smp_mb();
wake_up_bit(&inode->i_state, __I_SYNC);
@@ -306,24 +306,20 @@ static void inode_wait_for_writeback(struct inode *inode)
wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
while (inode->i_state & I_SYNC) {
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
}
}
/*
- * Write out an inode's dirty pages. Called under inode_lock. Either the
- * caller has a reference on the inode or the inode has I_WILL_FREE set.
+ * Write out an inode's dirty pages. Either the caller has a reference on the
+ * inode or the inode has I_WILL_FREE set.
*
* If `wait' is set, wait on the writeout.
*
* The whole writeout design is quite complex and fragile. We want to avoid
* starvation of particular inodes when others are being redirtied, prevent
* livelocks, etc.
- *
- * Called under inode_lock.
*/
static int
writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
@@ -368,7 +364,6 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
inode->i_state |= I_SYNC;
inode->i_state &= ~I_DIRTY_PAGES;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
ret = do_writepages(mapping, wbc);
@@ -388,12 +383,10 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
* due to delalloc, clear dirty metadata flags right before
* write_inode()
*/
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
/* Don't write the inode if only I_DIRTY_PAGES was set */
if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
int err = write_inode(inode, wbc);
@@ -401,7 +394,6 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
ret = err;
}
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
inode->i_state &= ~I_SYNC;
if (!(inode->i_state & I_FREEING)) {
@@ -555,10 +547,8 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
redirty_tail(inode);
spin_unlock(&wb->b_lock);
}
- spin_unlock(&inode_lock);
iput(inode);
cond_resched();
- spin_lock(&inode_lock);
spin_lock(&wb->b_lock);
if (wbc->nr_to_write <= 0) {
wbc->more_io = 1;
@@ -578,9 +568,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
if (!wbc->wb_start)
wbc->wb_start = jiffies; /* livelock avoidance */
- spin_lock(&inode_lock);
spin_lock(&wb->b_lock);
-
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
@@ -600,7 +588,6 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
break;
}
spin_unlock(&wb->b_lock);
- spin_unlock(&inode_lock);
/* Leave any unwritten inodes on b_io */
}
@@ -609,13 +596,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
{
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- spin_lock(&inode_lock);
spin_lock(&wb->b_lock);
if (!wbc->for_kupdate || list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
writeback_sb_inodes(sb, wb, wbc, true);
spin_unlock(&wb->b_lock);
- spin_unlock(&inode_lock);
}
/*
@@ -725,7 +710,6 @@ static long wb_writeback(struct bdi_writeback *wb,
* become available for writeback. Otherwise
* we'll just busyloop.
*/
- spin_lock(&inode_lock);
if (!list_empty(&wb->b_more_io)) {
spin_lock(&wb->b_lock);
inode = list_entry(wb->b_more_io.prev,
@@ -736,7 +720,6 @@ static long wb_writeback(struct bdi_writeback *wb,
inode_wait_for_writeback(inode);
spin_unlock(&inode->i_lock);
}
- spin_unlock(&inode_lock);
}
return wrote;
@@ -999,7 +982,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
if (unlikely(block_dump))
block_dump___mark_inode_dirty(inode);
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
if ((inode->i_state & flags) != flags) {
const int was_dirty = inode->i_state & I_DIRTY;
@@ -1057,8 +1039,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
out_unlock:
spin_unlock(&inode->i_lock);
out:
- spin_unlock(&inode_lock);
-
if (wakeup_bdi)
bdi_wakeup_thread_delayed(bdi);
}
@@ -1091,7 +1071,6 @@ static void wait_sb_inodes(struct super_block *sb)
*/
WARN_ON(!rwsem_is_locked(&sb->s_umount));
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
/*
@@ -1114,14 +1093,12 @@ static void wait_sb_inodes(struct super_block *sb)
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
/*
- * We hold a reference to 'inode' so it couldn't have
- * been removed from s_inodes list while we dropped the
- * inode_lock. We cannot iput the inode now as we can
- * be holding the last reference and we cannot iput it
- * under inode_lock. So we keep the reference and iput
- * it later.
+ * We hold a reference to 'inode' so it couldn't have been
+ * removed from s_inodes list while we dropped the
+ * s_inodes_lock. We cannot iput the inode now as we can be
+ * holding the last reference and we cannot iput it under
+ * s_inodes_lock. So we keep the reference and iput it later.
*/
iput(old_inode);
old_inode = inode;
@@ -1130,11 +1107,9 @@ static void wait_sb_inodes(struct super_block *sb)
cond_resched();
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
}
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
iput(old_inode);
}
@@ -1237,9 +1212,7 @@ int write_inode_now(struct inode *inode, int sync)
wbc.nr_to_write = 0;
might_sleep();
- spin_lock(&inode_lock);
ret = writeback_single_inode(inode, &wbc);
- spin_unlock(&inode_lock);
if (sync)
inode_sync_wait(inode);
return ret;
@@ -1261,9 +1234,7 @@ int sync_inode(struct inode *inode, struct writeback_control *wbc)
{
int ret;
- spin_lock(&inode_lock);
ret = writeback_single_inode(inode, wbc);
- spin_unlock(&inode_lock);
return ret;
}
EXPORT_SYMBOL(sync_inode);
diff --git a/fs/inode.c b/fs/inode.c
index 434a49b..e58524d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -43,11 +43,9 @@
* inode_lru, i_lru
*
* Lock orders
- * inode_lock
* inode hash bucket lock
* inode->i_lock
*
- * inode_lock
* sb inode lock
* inode_lru_lock
* wb->b_lock
@@ -104,14 +102,6 @@ static LIST_HEAD(inode_lru);
static DEFINE_SPINLOCK(inode_lru_lock);
/*
- * A simple spinlock to protect the list manipulations.
- *
- * NOTE! You also have to own the lock if you change
- * the i_state of an inode while it is in use..
- */
-DEFINE_SPINLOCK(inode_lock);
-
-/*
* iprune_sem provides exclusion between the kswapd or try_to_free_pages
* icache shrinking path, and the umount path. Without this exclusion,
* by the time prune_icache calls iput for the inode whose pages it has
@@ -354,11 +344,9 @@ static void init_once(void *foo)
void iref(struct inode *inode)
{
WARN_ON(inode->i_ref < 1);
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
inode->i_ref++;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(iref);
@@ -409,22 +397,19 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval)
struct hlist_bl_head *b;
b = inode_hashtable + hash(inode->i_sb, hashval);
- spin_lock(&inode_lock);
hlist_bl_lock(b);
hlist_bl_add_head(&inode->i_hash, b);
hlist_bl_unlock(b);
- spin_unlock(&inode_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
/**
- * __remove_inode_hash - remove an inode from the hash
+ * remove_inode_hash - remove an inode from the hash
* @inode: inode to unhash
*
- * Remove an inode from the superblock. inode->i_lock must be
- * held.
+ * Remove an inode from the superblock.
*/
-static void __remove_inode_hash(struct inode *inode)
+void remove_inode_hash(struct inode *inode)
{
struct hlist_bl_head *b;
@@ -433,19 +418,6 @@ static void __remove_inode_hash(struct inode *inode)
hlist_bl_del_init(&inode->i_hash);
hlist_bl_unlock(b);
}
-
-/**
- * remove_inode_hash - remove an inode from the hash
- * @inode: inode to unhash
- *
- * Remove an inode from the superblock.
- */
-void remove_inode_hash(struct inode *inode)
-{
- spin_lock(&inode_lock);
- __remove_inode_hash(inode);
- spin_unlock(&inode_lock);
-}
EXPORT_SYMBOL(remove_inode_hash);
void end_writeback(struct inode *inode)
@@ -496,12 +468,10 @@ static void dispose_list(struct list_head *head)
evict(inode);
- spin_lock(&inode_lock);
- __remove_inode_hash(inode);
+ remove_inode_hash(inode);
spin_lock(&inode->i_sb->s_inodes_lock);
list_del_init(&inode->i_sb_list);
spin_unlock(&inode->i_sb->s_inodes_lock);
- spin_unlock(&inode_lock);
wake_up_inode(inode);
destroy_inode(inode);
@@ -528,7 +498,6 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
* change during umount anymore, and because iprune_sem keeps
* shrink_icache_memory() away.
*/
- cond_resched_lock(&inode_lock);
cond_resched_lock(&sb->s_inodes_lock);
next = next->next;
@@ -579,12 +548,10 @@ int invalidate_inodes(struct super_block *sb)
LIST_HEAD(throw_away);
down_write(&iprune_sem);
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
fsnotify_unmount_inodes(&sb->s_inodes);
busy = invalidate_list(sb, &sb->s_inodes, &throw_away);
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
dispose_list(&throw_away);
up_write(&iprune_sem);
@@ -609,7 +576,7 @@ static int can_unuse(struct inode *inode)
/*
* Scan `goal' inodes on the unused list for freeable ones. They are moved to a
- * temporary list and then are freed outside inode_lock by dispose_list().
+ * temporary list and then are freed outside locks by dispose_list().
*
* Any inodes which are pinned purely because of attached pagecache have their
* pagecache removed. If the inode has metadata buffers attached to
@@ -630,7 +597,6 @@ static void prune_icache(int nr_to_scan)
unsigned long reap = 0;
down_read(&iprune_sem);
- spin_lock(&inode_lock);
spin_lock(&inode_lru_lock);
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;
@@ -663,12 +629,10 @@ static void prune_icache(int nr_to_scan)
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&inode_lru_lock);
- spin_unlock(&inode_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
- spin_lock(&inode_lock);
spin_lock(&inode_lru_lock);
spin_lock(&inode->i_lock);
@@ -703,7 +667,6 @@ static void prune_icache(int nr_to_scan)
else
__count_vm_events(PGINODESTEAL, reap);
spin_unlock(&inode_lru_lock);
- spin_unlock(&inode_lock);
dispose_list(&freeable);
up_read(&iprune_sem);
@@ -824,9 +787,9 @@ __inode_add_to_lists(struct super_block *sb, struct hlist_bl_head *b,
* @inode: inode to mark in use
*
* When an inode is allocated it needs to be accounted for, added to the in use
- * list, the owning superblock and the inode hash. This needs to be done under
- * the inode_lock, so export a function to do this rather than the inode lock
- * itself. We calculate the hash list to add to here so it is all internal
+ * list, the owning superblock and the inode hash.
+ *
+ * We calculate the hash list to add to here so it is all internal
* which requires the caller to have already set up the inode number in the
* inode to add.
*/
@@ -834,9 +797,7 @@ void inode_add_to_lists(struct super_block *sb, struct inode *inode)
{
struct hlist_bl_head *b = inode_hashtable + hash(sb, inode->i_ino);
- spin_lock(&inode_lock);
__inode_add_to_lists(sb, b, inode);
- spin_unlock(&inode_lock);
}
EXPORT_SYMBOL_GPL(inode_add_to_lists);
@@ -893,12 +854,8 @@ struct inode *new_inode(struct super_block *sb)
{
struct inode *inode;
- spin_lock_prefetch(&inode_lock);
-
inode = alloc_inode(sb);
if (inode) {
- spin_lock(&inode_lock);
-
/*
* set the inode state before we make the inode accessible to
* the outside world.
@@ -906,7 +863,6 @@ struct inode *new_inode(struct super_block *sb)
inode->i_ino = get_next_ino();
inode->i_state = 0;
__inode_add_to_lists(sb, NULL, inode);
- spin_unlock(&inode_lock);
}
return inode;
}
@@ -965,7 +921,6 @@ static struct inode *get_new_inode(struct super_block *sb,
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
/* We released the lock, so.. */
old = find_inode(sb, b, test, data);
if (!old) {
@@ -978,7 +933,6 @@ static struct inode *get_new_inode(struct super_block *sb,
*/
inode->i_state = I_NEW;
__inode_add_to_lists(sb, b, inode);
- spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
@@ -993,7 +947,6 @@ static struct inode *get_new_inode(struct super_block *sb,
*/
old->i_ref++;
spin_unlock(&old->i_lock);
- spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
@@ -1001,7 +954,6 @@ static struct inode *get_new_inode(struct super_block *sb,
return inode;
set_failed:
- spin_unlock(&inode_lock);
destroy_inode(inode);
return NULL;
}
@@ -1019,7 +971,6 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, b, ino);
if (!old) {
@@ -1030,7 +981,6 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
inode->i_ino = ino;
inode->i_state = I_NEW;
__inode_add_to_lists(sb, b, inode);
- spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
@@ -1045,7 +995,6 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
*/
old->i_ref++;
spin_unlock(&old->i_lock);
- spin_unlock(&inode_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
@@ -1116,7 +1065,6 @@ EXPORT_SYMBOL(iunique);
struct inode *igrab(struct inode *inode)
{
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
inode->i_ref++;
@@ -1130,7 +1078,6 @@ struct inode *igrab(struct inode *inode)
*/
inode = NULL;
}
- spin_unlock(&inode_lock);
return inode;
}
EXPORT_SYMBOL(igrab);
@@ -1152,7 +1099,7 @@ EXPORT_SYMBOL(igrab);
*
* Otherwise NULL is returned.
*
- * Note, @test is called with the inode_lock held, so can't sleep.
+ * Note, @test is called with the i_lock held, so can't sleep.
*/
static struct inode *ifind(struct super_block *sb,
struct hlist_bl_head *b,
@@ -1161,17 +1108,14 @@ static struct inode *ifind(struct super_block *sb,
{
struct inode *inode;
- spin_lock(&inode_lock);
inode = find_inode(sb, b, test, data);
if (inode) {
inode->i_ref++;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
if (likely(wait))
wait_on_inode(inode);
return inode;
}
- spin_unlock(&inode_lock);
return NULL;
}
@@ -1196,16 +1140,13 @@ static struct inode *ifind_fast(struct super_block *sb,
{
struct inode *inode;
- spin_lock(&inode_lock);
inode = find_inode_fast(sb, b, ino);
if (inode) {
inode->i_ref++;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
wait_on_inode(inode);
return inode;
}
- spin_unlock(&inode_lock);
return NULL;
}
@@ -1228,7 +1169,7 @@ static struct inode *ifind_fast(struct super_block *sb,
*
* Otherwise NULL is returned.
*
- * Note, @test is called with the inode_lock held, so can't sleep.
+ * Note, @test is called with the i_lock held, so can't sleep.
*/
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
@@ -1256,7 +1197,7 @@ EXPORT_SYMBOL(ilookup5_nowait);
*
* Otherwise NULL is returned.
*
- * Note, @test is called with the inode_lock held, so can't sleep.
+ * Note, @test is called with the i_lock held, so can't sleep.
*/
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
@@ -1307,7 +1248,7 @@ EXPORT_SYMBOL(ilookup);
* inode and this is returned locked, hashed, and with the I_NEW flag set. The
* file system gets to fill it in before unlocking it via unlock_new_inode().
*
- * Note both @test and @set are called with the inode_lock held, so can't sleep.
+ * Note both @test and @set are called with the i_lock held, so can't sleep.
*/
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *),
@@ -1368,7 +1309,6 @@ int insert_inode_locked(struct inode *inode)
while (1) {
struct hlist_bl_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
hlist_bl_lock(b);
hlist_bl_for_each_entry(old, node, b, i_hash) {
if (old->i_ino != ino)
@@ -1385,13 +1325,11 @@ int insert_inode_locked(struct inode *inode)
if (likely(!node)) {
hlist_bl_add_head(&inode->i_hash, b);
hlist_bl_unlock(b);
- spin_unlock(&inode_lock);
return 0;
}
old->i_ref++;
spin_unlock(&old->i_lock);
hlist_bl_unlock(b);
- spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
@@ -1418,7 +1356,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
struct hlist_bl_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
hlist_bl_lock(b);
hlist_bl_for_each_entry(old, node, b, i_hash) {
if (old->i_sb != sb)
@@ -1435,13 +1372,11 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
if (likely(!node)) {
hlist_bl_add_head(&inode->i_hash, b);
hlist_bl_unlock(b);
- spin_unlock(&inode_lock);
return 0;
}
old->i_ref++;
spin_unlock(&old->i_lock);
hlist_bl_unlock(b);
- spin_unlock(&inode_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
@@ -1503,16 +1438,13 @@ static void iput_final(struct inode *inode)
return;
}
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
return;
}
WARN_ON(inode->i_state & I_NEW);
inode->i_state |= I_WILL_FREE;
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
write_inode_now(inode, 1);
- spin_lock(&inode_lock);
- __remove_inode_hash(inode);
+ remove_inode_hash(inode);
spin_lock(&inode->i_lock);
WARN_ON(inode->i_state & I_NEW);
inode->i_state &= ~I_WILL_FREE;
@@ -1533,7 +1465,6 @@ static void iput_final(struct inode *inode)
list_del_init(&inode->i_sb_list);
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
evict(inode);
remove_inode_hash(inode);
wake_up_inode(inode);
@@ -1553,7 +1484,6 @@ static void iput_final(struct inode *inode)
void iput(struct inode *inode)
{
if (inode) {
- spin_lock(&inode_lock);
spin_lock(&inode->i_lock);
BUG_ON(inode->i_state & I_CLEAR);
@@ -1562,7 +1492,6 @@ void iput(struct inode *inode)
return;
}
spin_unlock(&inode->i_lock);
- spin_lock(&inode_lock);
}
}
EXPORT_SYMBOL(iput);
@@ -1742,8 +1671,6 @@ EXPORT_SYMBOL(inode_wait);
* It doesn't matter if I_NEW is not set initially, a call to
* wake_up_inode() after removing from the hash list will DTRT.
*
- * This is called with inode_lock held.
- *
* Called with i_lock held and returns with it dropped.
*/
static void __wait_on_freeing_inode(struct inode *inode)
@@ -1753,10 +1680,8 @@ static void __wait_on_freeing_inode(struct inode *inode)
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
schedule();
finish_wait(wq, &wait.wait);
- spin_lock(&inode_lock);
}
static __initdata unsigned long ihash_entries;
diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c
index d8c71ec..a67b607 100644
--- a/fs/logfs/inode.c
+++ b/fs/logfs/inode.c
@@ -286,7 +286,7 @@ static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc)
return ret;
}
-/* called with inode_lock held */
+/* called with i_lock held */
static int logfs_drop_inode(struct inode *inode)
{
struct logfs_super *super = logfs_super(inode->i_sb);
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 203146b..2f8356f 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -22,7 +22,7 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
-#include <linux/writeback.h> /* for inode_lock */
+#include <linux/writeback.h>
#include <asm/atomic.h>
@@ -232,9 +232,8 @@ out:
* fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
* @list: list of inodes being unmounted (sb->s_inodes)
*
- * Called with inode_lock held, protecting the unmounting super block's list
- * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay.
- * We temporarily drop inode_lock, however, and CAN block.
+ * Called with iprune_mutex held, keeping shrink_icache_memory() at bay.
+ * sb_inode_list_lock to protect the super block's list of inodes.
*/
void fsnotify_unmount_inodes(struct list_head *list)
{
@@ -288,13 +287,12 @@ void fsnotify_unmount_inodes(struct list_head *list)
}
/*
- * We can safely drop inode_lock here because we hold
+ * We can safely drop sb->s_inodes_lock here because we hold
* references on both inode and next_i. Also no new inodes
* will be added since the umount has begun. Finally,
* iprune_mutex keeps shrink_icache_memory() away.
*/
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
if (need_iput_tmp)
iput(need_iput_tmp);
@@ -306,7 +304,6 @@ void fsnotify_unmount_inodes(struct list_head *list)
iput(inode);
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
}
}
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 325185e..50c0085 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -91,7 +91,6 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/srcu.h>
-#include <linux/writeback.h> /* for inode_lock */
#include <asm/atomic.h>
diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index 56772b5..6f8eefe 100644
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -23,7 +23,6 @@
#include <linux/mount.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
-#include <linux/writeback.h> /* for inode_lock */
#include <asm/atomic.h>
diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 07fdef8..9b9375a 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -54,7 +54,7 @@
*
* Return 1 if the attributes match and 0 if not.
*
- * NOTE: This function runs with the inode_lock spin lock held so it is not
+ * NOTE: This function runs with the i_lock spin lock held so it is not
* allowed to sleep.
*/
int ntfs_test_inode(struct inode *vi, ntfs_attr *na)
@@ -98,7 +98,7 @@ int ntfs_test_inode(struct inode *vi, ntfs_attr *na)
*
* Return 0 on success and -errno on error.
*
- * NOTE: This function runs with the inode_lock spin lock held so it is not
+ * NOTE: This function runs with the i_lock spin lock held so it is not
* allowed to sleep. (Hence the GFP_ATOMIC allocation.)
*/
static int ntfs_init_locked_inode(struct inode *vi, ntfs_attr *na)
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index eece3e0..65c61e2 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1195,7 +1195,7 @@ void ocfs2_evict_inode(struct inode *inode)
ocfs2_clear_inode(inode);
}
-/* Called under inode_lock, with no more references on the
+/* Called under i_lock, with no more references on the
* struct inode, so it's safe here to check the flags field
* and to manipulate i_nlink without any other locks. */
int ocfs2_drop_inode(struct inode *inode)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index b02a3e1..178bed4 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -76,7 +76,7 @@
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
-#include <linux/writeback.h> /* for inode_lock, oddly enough.. */
+#include <linux/writeback.h>
#include <asm/uaccess.h>
@@ -896,7 +896,6 @@ static void add_dquot_ref(struct super_block *sb, int type)
int reserved = 0;
#endif
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
@@ -914,21 +913,18 @@ static void add_dquot_ref(struct super_block *sb, int type)
inode->i_ref++;
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
iput(old_inode);
__dquot_initialize(inode, type);
/* We hold a reference to 'inode' so it couldn't have been
- * removed from s_inodes list while we dropped the inode_lock.
+ * removed from s_inodes list while we dropped the lock.
* We cannot iput the inode now as we can be holding the last
- * reference and we cannot iput it under inode_lock. So we
+ * reference and we cannot iput it under the lock. So we
* keep the reference and iput it later. */
old_inode = inode;
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
}
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
iput(old_inode);
#ifdef CONFIG_QUOTA_DEBUG
@@ -1009,7 +1005,6 @@ static void remove_dquot_ref(struct super_block *sb, int type,
struct inode *inode;
int reserved = 0;
- spin_lock(&inode_lock);
spin_lock(&sb->s_inodes_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
@@ -1025,7 +1020,6 @@ static void remove_dquot_ref(struct super_block *sb, int type,
}
}
spin_unlock(&sb->s_inodes_lock);
- spin_unlock(&inode_lock);
#ifdef CONFIG_QUOTA_DEBUG
if (reserved) {
printk(KERN_WARNING "VFS (%s): Writes happened after quota"
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 767913a..816b471 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1593,7 +1593,7 @@ struct super_operations {
};
/*
- * Inode state bits. Protected by inode_lock.
+ * Inode state bits. Protected by i_lock.
*
* Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
* I_DIRTY_DATASYNC and I_DIRTY_PAGES.
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 242b6f8..fa38cf0 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -9,8 +9,6 @@
struct backing_dev_info;
-extern spinlock_t inode_lock;
-
/*
* fs/fs-writeback.c
*/
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 2cdb7a8..5703f35 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -73,7 +73,6 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
struct inode *inode;
nr_wb = nr_dirty = nr_io = nr_more_io = 0;
- spin_lock(&inode_lock);
spin_lock(&wb->b_lock);
list_for_each_entry(inode, &wb->b_dirty, i_wb_list)
nr_dirty++;
@@ -82,7 +81,6 @@ static int bdi_debug_stats_show(struct seq_file *m, void *v)
list_for_each_entry(inode, &wb->b_more_io, i_wb_list)
nr_more_io++;
spin_unlock(&wb->b_lock);
- spin_unlock(&inode_lock);
global_dirty_limits(&background_thresh, &dirty_thresh);
bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
@@ -697,14 +695,12 @@ void bdi_destroy(struct backing_dev_info *bdi)
if (bdi_has_dirty_io(bdi)) {
struct bdi_writeback *dst = &default_backing_dev_info.wb;
- spin_lock(&inode_lock);
bdi_lock_two(bdi, &default_backing_dev_info);
list_splice(&bdi->wb.b_dirty, &dst->b_dirty);
list_splice(&bdi->wb.b_io, &dst->b_io);
list_splice(&bdi->wb.b_more_io, &dst->b_more_io);
spin_unlock(&bdi->wb.b_lock);
spin_unlock(&dst->b_lock);
- spin_unlock(&inode_lock);
}
bdi_unregister(bdi);
diff --git a/mm/filemap.c b/mm/filemap.c
index 3d4df44..ece6ef2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -80,7 +80,7 @@
* ->i_mutex
* ->i_alloc_sem (various)
*
- * ->inode_lock
+ * ->i_lock
* ->sb_lock (fs/fs-writeback.c)
* ->mapping->tree_lock (__sync_single_inode)
*
@@ -98,8 +98,8 @@
* ->zone.lru_lock (check_pte_range->isolate_lru_page)
* ->private_lock (page_remove_rmap->set_page_dirty)
* ->tree_lock (page_remove_rmap->set_page_dirty)
- * ->inode_lock (page_remove_rmap->set_page_dirty)
- * ->inode_lock (zap_pte_range->set_page_dirty)
+ * ->i_lock (page_remove_rmap->set_page_dirty)
+ * ->i_lock (zap_pte_range->set_page_dirty)
* ->private_lock (zap_pte_range->__set_page_dirty_buffers)
*
* ->task->proc_lock
diff --git a/mm/rmap.c b/mm/rmap.c
index 92e6757..dbfccae 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -31,11 +31,11 @@
* swap_lock (in swap_duplicate, swap_info_get)
* mmlist_lock (in mmput, drain_mmlist and others)
* mapping->private_lock (in __set_page_dirty_buffers)
- * inode_lock (in set_page_dirty's __mark_inode_dirty)
- * sb_lock (within inode_lock in fs/fs-writeback.c)
+ * i_lock (in set_page_dirty's __mark_inode_dirty)
+ * sb_lock (within i_lock in fs/fs-writeback.c)
* mapping->tree_lock (widely used, in set_page_dirty,
* in arch-dependent flush_dcache_mmap_lock,
- * within inode_lock in __sync_single_inode)
+ * within i_lock in __sync_single_inode)
*
* (code doesn't rely on that order so it could be switched around)
* ->tasklist_lock
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (14 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 15/18] fs: icache remove inode_lock Dave Chinner
@ 2010-10-13 0:15 ` Dave Chinner
2010-10-13 13:51 ` Christoph Hellwig
2010-10-13 0:16 ` [PATCH 17/18] fs: split __inode_add_to_list Dave Chinner
` (2 subsequent siblings)
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:15 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Dave Chinner <dchinner@redhat.com>
Inode reclaim can push many inodes into the I_FREEING state before
it actually frees them. During the time it gathers these inodes, it
can call iput(), invalidate_mapping_pages, be preempted, etc. As a
result, holding inodes in I_FREEING can cause pauses.
After the inode scalability work, there is not a big reason to batch
up inodes to reclaim them, so we can dispose them as they are found
from the LRU.
Unmount does a very similar reclaim process via invalidate_list(),
but currently uses the i_lru list to aggregate inodes for a batched
disposal. This requires taking the inode_lru_lock for every inode we
want to dispose. Instead, take the inodes off the superblock inode
list (as we already hold the lock) and use i_sb_list as the
aggregator for inodes to dispose to reduce lock traffic.
Further, iput_final() does the same inode cleanup as reclaim and
unmount, so convert them all to use a single function for destroying
inodes. This is written such that the callers can optimise list
removals to avoid unneccessary lock round trips when removing inodes
from lists.
Based on a patch originally from Nick Piggin.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/inode.c | 116 +++++++++++++++++++++++++++++++++---------------------------
1 files changed, 64 insertions(+), 52 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index e58524d..5fed0e5 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -31,6 +31,8 @@
/*
* Locking rules.
*
+ * inode->i_lock is *always* the innermost lock.
+ *
* inode->i_lock protects:
* i_ref i_state
* inode hash lock protects:
@@ -48,8 +50,15 @@
*
* sb inode lock
* inode_lru_lock
- * wb->b_lock
- * inode->i_lock
+ * wb->b_lock
+ * inode->i_lock
+ *
+ * wb->b_lock
+ * sb_lock (pin sb for writeback)
+ * inode->i_lock
+ *
+ * inode_lru
+ * inode->i_lock
*/
/*
* This is needed for the following functions:
@@ -452,6 +461,44 @@ static void evict(struct inode *inode)
}
/*
+ * Free the inode passed in, removing it from the lists it is still connected
+ * to but avoiding unnecessary lock round-trips for the lists it is no longer
+ * on.
+ *
+ * An inode must already be marked I_FREEING so that we avoid the inode being
+ * moved back onto lists if we race with other code that manipulates the lists
+ * (e.g. writeback_single_inode). The caller
+ */
+static void dispose_one_inode(struct inode *inode)
+{
+ BUG_ON(!(inode->i_state & I_FREEING));
+
+ /*
+ * move the inode off the IO lists and LRU once
+ * I_FREEING is set so that it won't get moved back on
+ * there if it is dirty.
+ */
+ if (!list_empty(&inode->i_wb_list))
+ inode_wb_list_del(inode);
+
+ if (!list_empty(&inode->i_lru))
+ inode_lru_list_del(inode);
+
+ if (!list_empty(&inode->i_sb_list)) {
+ spin_lock(&inode->i_sb->s_inodes_lock);
+ list_del_init(&inode->i_sb_list);
+ spin_unlock(&inode->i_sb->s_inodes_lock);
+ }
+
+ evict(inode);
+
+ remove_inode_hash(inode);
+ wake_up_inode(inode);
+ BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
+ destroy_inode(inode);
+}
+
+/*
* dispose_list - dispose of the contents of a local list
* @head: the head of the list to free
*
@@ -463,18 +510,10 @@ static void dispose_list(struct list_head *head)
while (!list_empty(head)) {
struct inode *inode;
- inode = list_first_entry(head, struct inode, i_lru);
- list_del_init(&inode->i_lru);
-
- evict(inode);
-
- remove_inode_hash(inode);
- spin_lock(&inode->i_sb->s_inodes_lock);
+ inode = list_first_entry(head, struct inode, i_sb_list);
list_del_init(&inode->i_sb_list);
- spin_unlock(&inode->i_sb->s_inodes_lock);
- wake_up_inode(inode);
- destroy_inode(inode);
+ dispose_one_inode(inode);
}
}
@@ -515,17 +554,8 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
inode->i_state |= I_FREEING;
spin_unlock(&inode->i_lock);
- /*
- * move the inode off the IO lists and LRU once
- * I_FREEING is set so that it won't get moved back on
- * there if it is dirty.
- */
- inode_wb_list_del(inode);
-
- spin_lock(&inode_lru_lock);
- list_move(&inode->i_lru, dispose);
- percpu_counter_dec(&nr_inodes_unused);
- spin_unlock(&inode_lru_lock);
+ /* save a lock round trip by removing the inode here. */
+ list_move(&inode->i_sb_list, dispose);
continue;
}
spin_unlock(&inode->i_lock);
@@ -544,17 +574,17 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
*/
int invalidate_inodes(struct super_block *sb)
{
- int busy;
LIST_HEAD(throw_away);
+ int busy;
down_write(&iprune_sem);
spin_lock(&sb->s_inodes_lock);
fsnotify_unmount_inodes(&sb->s_inodes);
busy = invalidate_list(sb, &sb->s_inodes, &throw_away);
spin_unlock(&sb->s_inodes_lock);
+ up_write(&iprune_sem);
dispose_list(&throw_away);
- up_write(&iprune_sem);
return busy;
}
@@ -592,7 +622,6 @@ static int can_unuse(struct inode *inode)
*/
static void prune_icache(int nr_to_scan)
{
- LIST_HEAD(freeable);
int nr_scanned;
unsigned long reap = 0;
@@ -652,15 +681,15 @@ static void prune_icache(int nr_to_scan)
inode->i_state |= I_FREEING;
spin_unlock(&inode->i_lock);
- /*
- * move the inode off the io lists and lru once
- * i_freeing is set so that it won't get moved back on
- * there if it is dirty.
- */
- inode_wb_list_del(inode);
-
- list_move(&inode->i_lru, &freeable);
+ /* save a lock round trip by removing the inode here. */
+ list_del_init(&inode->i_lru);
percpu_counter_dec(&nr_inodes_unused);
+ spin_unlock(&inode_lru_lock);
+
+ dispose_one_inode(inode);
+ cond_resched();
+
+ spin_lock(&inode_lru_lock);
}
if (current_is_kswapd())
__count_vm_events(KSWAPD_INODESTEAL, reap);
@@ -668,7 +697,6 @@ static void prune_icache(int nr_to_scan)
__count_vm_events(PGINODESTEAL, reap);
spin_unlock(&inode_lru_lock);
- dispose_list(&freeable);
up_read(&iprune_sem);
}
@@ -1453,23 +1481,7 @@ static void iput_final(struct inode *inode)
inode->i_state |= I_FREEING;
spin_unlock(&inode->i_lock);
- /*
- * After we delete the inode from the LRU and IO lists here, we avoid
- * moving dirty inodes back onto the LRU now because I_FREEING is set
- * and hence writeback_single_inode() won't move the inode around.
- */
- inode_wb_list_del(inode);
- inode_lru_list_del(inode);
-
- spin_lock(&sb->s_inodes_lock);
- list_del_init(&inode->i_sb_list);
- spin_unlock(&sb->s_inodes_lock);
-
- evict(inode);
- remove_inode_hash(inode);
- wake_up_inode(inode);
- BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
- destroy_inode(inode);
+ dispose_one_inode(inode);
}
/**
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 17/18] fs: split __inode_add_to_list
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (15 preceding siblings ...)
2010-10-13 0:15 ` [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
@ 2010-10-13 0:16 ` Dave Chinner
2010-10-13 15:08 ` Christoph Hellwig
2010-10-13 0:16 ` [PATCH 18/18] fs: do not assign default i_ino in new_inode Dave Chinner
2010-10-13 14:51 ` fs: Inode cache scalability V3 Christoph Hellwig
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:16 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Christoph Hellwig <hch@lst.de>
__inode_add_to_list does two things that aren't related. First it adds
the inode to the s_inodes list in the superblock, and second it optionally
adds the inode to the inode hash. Now that these don't even share the
same lock there is no need to keeps this functionally together. Split
out an add_to_inode_hash helper from __insert_inode_hash to add an inode
to a pre-calculated hash bucket for use by the various iget version, and
a inode_sb_list_add helper from __inode_add_to_list to just add an
inode to the per-sb list. The inode.c-internal callers of
__inode_add_to_list are converted to a sequence of inode_sb_list_add
and __insert_inode_hash (if needed), and the only use of inode_add_to_list
in XFS is replaced with a call to inode_sb_list_add and insert_inode_hash.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/inode.c | 80 ++++++++++++++++++++-----------------------
fs/xfs/linux-2.6/xfs_iops.c | 4 ++-
include/linux/fs.h | 5 ++-
3 files changed, 43 insertions(+), 46 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 5fed0e5..2685460 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -383,6 +383,29 @@ void inode_lru_list_del(struct inode *inode)
spin_unlock(&inode_lru_lock);
}
+/**
+ * inode_sb_list_add - add inode to the superblock list of inodes
+ * @inode: inode to add
+ */
+void inode_sb_list_add(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ spin_lock(&sb->s_inodes_lock);
+ list_add(&inode->i_sb_list, &sb->s_inodes);
+ spin_unlock(&sb->s_inodes_lock);
+}
+EXPORT_SYMBOL_GPL(inode_sb_list_add);
+
+static void inode_sb_list_del(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ spin_lock(&sb->s_inodes_lock);
+ list_del_init(&inode->i_sb_list);
+ spin_unlock(&sb->s_inodes_lock);
+}
+
static unsigned long hash(struct super_block *sb, unsigned long hashval)
{
unsigned long tmp;
@@ -393,6 +416,13 @@ static unsigned long hash(struct super_block *sb, unsigned long hashval)
return tmp & I_HASHMASK;
}
+static void inode_hash_list_add(struct hlist_bl_head *b, struct inode *inode)
+{
+ hlist_bl_lock(b);
+ hlist_bl_add_head(&inode->i_hash, b);
+ hlist_bl_unlock(b);
+}
+
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
@@ -406,9 +436,7 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval)
struct hlist_bl_head *b;
b = inode_hashtable + hash(inode->i_sb, hashval);
- hlist_bl_lock(b);
- hlist_bl_add_head(&inode->i_hash, b);
- hlist_bl_unlock(b);
+ inode_hash_list_add(b, inode);
}
EXPORT_SYMBOL(__insert_inode_hash);
@@ -485,9 +513,7 @@ static void dispose_one_inode(struct inode *inode)
inode_lru_list_del(inode);
if (!list_empty(&inode->i_sb_list)) {
- spin_lock(&inode->i_sb->s_inodes_lock);
- list_del_init(&inode->i_sb_list);
- spin_unlock(&inode->i_sb->s_inodes_lock);
+ inode_sb_list_del(inode);
}
evict(inode);
@@ -795,40 +821,6 @@ repeat:
return node ? inode : NULL;
}
-static inline void
-__inode_add_to_lists(struct super_block *sb, struct hlist_bl_head *b,
- struct inode *inode)
-{
- spin_lock(&sb->s_inodes_lock);
- list_add(&inode->i_sb_list, &sb->s_inodes);
- spin_unlock(&sb->s_inodes_lock);
- if (b) {
- hlist_bl_lock(b);
- hlist_bl_add_head(&inode->i_hash, b);
- hlist_bl_unlock(b);
- }
-}
-
-/**
- * inode_add_to_lists - add a new inode to relevant lists
- * @sb: superblock inode belongs to
- * @inode: inode to mark in use
- *
- * When an inode is allocated it needs to be accounted for, added to the in use
- * list, the owning superblock and the inode hash.
- *
- * We calculate the hash list to add to here so it is all internal
- * which requires the caller to have already set up the inode number in the
- * inode to add.
- */
-void inode_add_to_lists(struct super_block *sb, struct inode *inode)
-{
- struct hlist_bl_head *b = inode_hashtable + hash(sb, inode->i_ino);
-
- __inode_add_to_lists(sb, b, inode);
-}
-EXPORT_SYMBOL_GPL(inode_add_to_lists);
-
/*
* Each cpu owns a range of LAST_INO_BATCH numbers.
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
@@ -890,7 +882,7 @@ struct inode *new_inode(struct super_block *sb)
*/
inode->i_ino = get_next_ino();
inode->i_state = 0;
- __inode_add_to_lists(sb, NULL, inode);
+ inode_sb_list_add(inode);
}
return inode;
}
@@ -960,7 +952,8 @@ static struct inode *get_new_inode(struct super_block *sb,
* visible to the outside world.
*/
inode->i_state = I_NEW;
- __inode_add_to_lists(sb, b, inode);
+ inode_sb_list_add(inode);
+ inode_hash_list_add(b, inode);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
@@ -1008,7 +1001,8 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
*/
inode->i_ino = ino;
inode->i_state = I_NEW;
- __inode_add_to_lists(sb, b, inode);
+ inode_sb_list_add(inode);
+ inode_hash_list_add(b, inode);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index b7ec465..3c7cea3 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -795,7 +795,9 @@ xfs_setup_inode(
inode->i_ino = ip->i_ino;
inode->i_state = I_NEW;
- inode_add_to_lists(ip->i_mount->m_super, inode);
+
+ inode_sb_list_add(inode);
+ insert_inode_hash(inode);
inode->i_mode = ip->i_d.di_mode;
inode->i_nlink = ip->i_d.di_nlink;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 816b471..041355b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2170,7 +2170,6 @@ extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin);
extern int inode_init_always(struct super_block *, struct inode *);
extern void inode_init_once(struct inode *);
-extern void inode_add_to_lists(struct super_block *, struct inode *);
extern void iput(struct inode *);
extern struct inode * igrab(struct inode *);
extern ino_t iunique(struct super_block *, ino_t);
@@ -2202,9 +2201,11 @@ extern int file_remove_suid(struct file *);
extern void __insert_inode_hash(struct inode *, unsigned long hashval);
extern void remove_inode_hash(struct inode *);
-static inline void insert_inode_hash(struct inode *inode) {
+static inline void insert_inode_hash(struct inode *inode)
+{
__insert_inode_hash(inode, inode->i_ino);
}
+extern void inode_sb_list_add(struct inode *inode);
#ifdef CONFIG_BLOCK
extern void submit_bio(int, struct bio *);
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* [PATCH 18/18] fs: do not assign default i_ino in new_inode
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (16 preceding siblings ...)
2010-10-13 0:16 ` [PATCH 17/18] fs: split __inode_add_to_list Dave Chinner
@ 2010-10-13 0:16 ` Dave Chinner
2010-10-16 7:57 ` Nick Piggin
2010-10-13 14:51 ` fs: Inode cache scalability V3 Christoph Hellwig
18 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 0:16 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
From: Christoph Hellwig <hch@lst.de>
Instead of always assigning an increasing inode number in new_inode
move the call to assign it into those callers that actually need it.
For now callers that need it is estimated conservatively, that is
the call is added to all filesystems that do not assign an i_ino
by themselves. For a few more filesystems we can avoid assigning
any inode number given that they aren't user visible, and for others
it could be done lazily when an inode number is actually needed,
but that's left for later patches.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
drivers/infiniband/hw/ipath/ipath_fs.c | 1 +
drivers/infiniband/hw/qib/qib_fs.c | 1 +
drivers/misc/ibmasm/ibmasmfs.c | 1 +
drivers/oprofile/oprofilefs.c | 1 +
drivers/usb/core/inode.c | 1 +
drivers/usb/gadget/f_fs.c | 1 +
drivers/usb/gadget/inode.c | 1 +
fs/anon_inodes.c | 1 +
fs/autofs4/inode.c | 1 +
fs/binfmt_misc.c | 1 +
fs/configfs/inode.c | 1 +
fs/debugfs/inode.c | 1 +
fs/ext4/mballoc.c | 1 +
fs/freevxfs/vxfs_inode.c | 1 +
fs/fuse/control.c | 1 +
fs/hugetlbfs/inode.c | 1 +
fs/inode.c | 3 ++-
fs/ocfs2/dlmfs/dlmfs.c | 2 ++
fs/pipe.c | 2 ++
fs/proc/base.c | 2 ++
fs/proc/proc_sysctl.c | 2 ++
fs/ramfs/inode.c | 1 +
fs/xfs/linux-2.6/xfs_buf.c | 1 +
include/linux/fs.h | 1 +
ipc/mqueue.c | 1 +
kernel/cgroup.c | 1 +
mm/shmem.c | 1 +
net/socket.c | 1 +
net/sunrpc/rpc_pipe.c | 1 +
security/inode.c | 1 +
security/selinux/selinuxfs.c | 1 +
31 files changed, 36 insertions(+), 1 deletions(-)
diff --git a/drivers/infiniband/hw/ipath/ipath_fs.c b/drivers/infiniband/hw/ipath/ipath_fs.c
index 2fca708..3d7c1df 100644
--- a/drivers/infiniband/hw/ipath/ipath_fs.c
+++ b/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -57,6 +57,7 @@ static int ipathfs_mknod(struct inode *dir, struct dentry *dentry,
goto bail;
}
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_private = data;
diff --git a/drivers/infiniband/hw/qib/qib_fs.c b/drivers/infiniband/hw/qib/qib_fs.c
index 9f989c0..0a8da2a 100644
--- a/drivers/infiniband/hw/qib/qib_fs.c
+++ b/drivers/infiniband/hw/qib/qib_fs.c
@@ -58,6 +58,7 @@ static int qibfs_mknod(struct inode *dir, struct dentry *dentry,
goto bail;
}
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = 0;
inode->i_gid = 0;
diff --git a/drivers/misc/ibmasm/ibmasmfs.c b/drivers/misc/ibmasm/ibmasmfs.c
index 8844a3f..1ebe935 100644
--- a/drivers/misc/ibmasm/ibmasmfs.c
+++ b/drivers/misc/ibmasm/ibmasmfs.c
@@ -146,6 +146,7 @@ static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
struct inode *ret = new_inode(sb);
if (ret) {
+ ret->i_ino = get_next_ino();
ret->i_mode = mode;
ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
}
diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c
index 2766a6d..5acc58d 100644
--- a/drivers/oprofile/oprofilefs.c
+++ b/drivers/oprofile/oprofilefs.c
@@ -28,6 +28,7 @@ static struct inode *oprofilefs_get_inode(struct super_block *sb, int mode)
struct inode *inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}
diff --git a/drivers/usb/core/inode.c b/drivers/usb/core/inode.c
index 095fa53..e2f63c0 100644
--- a/drivers/usb/core/inode.c
+++ b/drivers/usb/core/inode.c
@@ -276,6 +276,7 @@ static struct inode *usbfs_get_inode (struct super_block *sb, int mode, dev_t de
struct inode *inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index e4f5950..e093fd8 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -980,6 +980,7 @@ ffs_sb_make_inode(struct super_block *sb, void *data,
if (likely(inode)) {
struct timespec current_time = CURRENT_TIME;
+ inode->i_ino = usbfs_get_inode();
inode->i_mode = perms->mode;
inode->i_uid = perms->uid;
inode->i_gid = perms->gid;
diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c
index fc35406..136e78d 100644
--- a/drivers/usb/gadget/inode.c
+++ b/drivers/usb/gadget/inode.c
@@ -1994,6 +1994,7 @@ gadgetfs_make_inode (struct super_block *sb,
struct inode *inode = new_inode (sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = default_uid;
inode->i_gid = default_gid;
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 451be78..327c484 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -189,6 +189,7 @@ static struct inode *anon_inode_mkinode(void)
if (!inode)
return ERR_PTR(-ENOMEM);
+ inode->i_ino = get_next_ino();
inode->i_fop = &anon_inode_fops;
inode->i_mapping->a_ops = &anon_aops;
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 821b2b9..ac87e49 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -398,6 +398,7 @@ struct inode *autofs4_get_inode(struct super_block *sb,
inode->i_gid = sb->s_root->d_inode->i_gid;
}
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ inode->i_ino = get_next_ino();
if (S_ISDIR(inf->mode)) {
inode->i_nlink = 2;
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index fd0cc0b..37c4aef 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -495,6 +495,7 @@ static struct inode *bm_get_inode(struct super_block *sb, int mode)
struct inode * inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime =
current_fs_time(inode->i_sb);
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index cf78d44..253476d 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -135,6 +135,7 @@ struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
{
struct inode * inode = new_inode(configfs_sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mapping->a_ops = &configfs_aops;
inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
inode->i_op = &configfs_inode_operations;
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 30a87b3..a4ed838 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -40,6 +40,7 @@ static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t d
struct inode *inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 4b4ad4b..96e2bf3 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2373,6 +2373,7 @@ static int ext4_mb_init_backend(struct super_block *sb)
printk(KERN_ERR "EXT4-fs: can't get new inode\n");
goto err_freesgi;
}
+ sbi->s_buddy_cache->i_ino = get_next_ino();
EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
for (i = 0; i < ngroups; i++) {
desc = ext4_get_group_desc(sb, i, NULL);
diff --git a/fs/freevxfs/vxfs_inode.c b/fs/freevxfs/vxfs_inode.c
index 79d1b4e..8c04eac 100644
--- a/fs/freevxfs/vxfs_inode.c
+++ b/fs/freevxfs/vxfs_inode.c
@@ -260,6 +260,7 @@ vxfs_get_fake_inode(struct super_block *sbp, struct vxfs_inode_info *vip)
struct inode *ip = NULL;
if ((ip = new_inode(sbp))) {
+ ip->i_ino = get_next_ino();
vxfs_iinit(ip, vip);
ip->i_mapping->a_ops = &vxfs_aops;
}
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 3773fd6..3f67de2 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -218,6 +218,7 @@ static struct dentry *fuse_ctl_add_dentry(struct dentry *parent,
if (!inode)
return NULL;
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = fc->user_id;
inode->i_gid = fc->group_id;
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 6e5bd42..b83f9ff 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -455,6 +455,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
inode = new_inode(sb);
if (inode) {
struct hugetlbfs_inode_info *info;
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = uid;
inode->i_gid = gid;
diff --git a/fs/inode.c b/fs/inode.c
index 2685460..1c451ab 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -839,7 +839,7 @@ repeat:
#define LAST_INO_BATCH 1024
static DEFINE_PER_CPU(unsigned int, last_ino);
-static unsigned int get_next_ino(void)
+unsigned int get_next_ino(void)
{
unsigned int *p = &get_cpu_var(last_ino);
unsigned int res = *p;
@@ -857,6 +857,7 @@ static unsigned int get_next_ino(void)
put_cpu_var(last_ino);
return res;
}
+EXPORT_SYMBOL(get_next_ino);
/**
* new_inode - obtain an inode
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index c2903b8..124d400 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -400,6 +400,7 @@ static struct inode *dlmfs_get_root_inode(struct super_block *sb)
if (inode) {
ip = DLMFS_I(inode);
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
@@ -425,6 +426,7 @@ static struct inode *dlmfs_get_inode(struct inode *parent,
if (!inode)
return NULL;
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
diff --git a/fs/pipe.c b/fs/pipe.c
index 279eef9..acd453b 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -954,6 +954,8 @@ static struct inode * get_pipe_inode(void)
if (!inode)
goto fail_inode;
+ inode->i_ino = get_next_ino();
+
pipe = alloc_pipe_info(inode);
if (!pipe)
goto fail_iput;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8e4adda..d2efd66 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1600,6 +1600,7 @@ static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_st
/* Common stuff */
ei = PROC_I(inode);
+ inode->i_ino = get_next_ino();
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_op = &proc_def_inode_operations;
@@ -2542,6 +2543,7 @@ static struct dentry *proc_base_instantiate(struct inode *dir,
/* Initialize the inode */
ei = PROC_I(inode);
+ inode->i_ino = get_next_ino();
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
/*
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 5be436e..f473a7b 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -23,6 +23,8 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
if (!inode)
goto out;
+ inode->i_ino = get_next_ino();
+
sysctl_head_get(head);
ei = PROC_I(inode);
ei->sysctl = head;
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index a5ebae7..67fadb1 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -58,6 +58,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,
struct inode * inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode_init_owner(inode, dir, mode);
inode->i_mapping->a_ops = &ramfs_aops;
inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 286e36e..a47e6db 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1572,6 +1572,7 @@ xfs_mapping_buftarg(
XFS_BUFTARG_NAME(btp));
return ENOMEM;
}
+ inode->i_ino = get_next_ino();
inode->i_mode = S_IFBLK;
inode->i_bdev = bdev;
inode->i_rdev = bdev->bd_dev;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 041355b..12eb318 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2189,6 +2189,7 @@ extern struct inode * iget_locked(struct super_block *, unsigned long);
extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
extern int insert_inode_locked(struct inode *);
extern void unlock_new_inode(struct inode *);
+extern unsigned int get_next_ino(void);
extern void iref(struct inode *inode);
extern void iget_failed(struct inode *);
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index d53a2c1..a72f3c5 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -116,6 +116,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c9483d8..e28f8e5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -778,6 +778,7 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
struct inode *inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
diff --git a/mm/shmem.c b/mm/shmem.c
index 419de2c..504ae65 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1586,6 +1586,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode_init_owner(inode, dir, mode);
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
diff --git a/net/socket.c b/net/socket.c
index 715ca57..56114ec 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -480,6 +480,7 @@ static struct socket *sock_alloc(void)
sock = SOCKET_I(inode);
kmemcheck_annotate_bitfield(sock, type);
+ inode->i_ino = get_next_ino();
inode->i_mode = S_IFSOCK | S_IRWXUGO;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 8c8eef2..70da9a4 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -453,6 +453,7 @@ rpc_get_inode(struct super_block *sb, umode_t mode)
struct inode *inode = new_inode(sb);
if (!inode)
return NULL;
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch(mode & S_IFMT) {
diff --git a/security/inode.c b/security/inode.c
index 8c777f0..d3321c2 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -60,6 +60,7 @@ static struct inode *get_inode(struct super_block *sb, int mode, dev_t dev)
struct inode *inode = new_inode(sb);
if (inode) {
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 79a1bb6..9e98cdc 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -785,6 +785,7 @@ static struct inode *sel_make_inode(struct super_block *sb, int mode)
struct inode *ret = new_inode(sb);
if (ret) {
+ ret->i_ino = get_next_ino();
ret->i_mode = mode;
ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
}
--
1.7.1
^ permalink raw reply related [flat|nested] 50+ messages in thread
* Re: [PATCH 15/18] fs: icache remove inode_lock
2010-10-13 0:15 ` [PATCH 15/18] fs: icache remove inode_lock Dave Chinner
@ 2010-10-13 2:09 ` Dave Chinner
2010-10-13 13:42 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 2:09 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
On Wed, Oct 13, 2010 at 11:15:58AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> All the functionality that the inode_lock protected has now been
> wrapped up in new independent locks and/or functionality. Hence the
> inode_lock does not serve a purpose any longer and hence can now be
> removed.
>
> Based on work originally done by Nick Piggin.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> Documentation/filesystems/Locking | 2 +-
> Documentation/filesystems/porting | 10 +++-
> Documentation/filesystems/vfs.txt | 2 +-
I forgot to update these files again. I will send another version of
this patch when I've done it.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 11/18] fs: split locking of inode writeback and LRU lists
2010-10-13 0:15 ` [PATCH 11/18] fs: split locking of inode writeback and LRU lists Dave Chinner
@ 2010-10-13 3:26 ` Lin Ming
2010-10-13 13:18 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Lin Ming @ 2010-10-13 3:26 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 8:15 AM, Dave Chinner <david@fromorbit.com> wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Given that the inode LRU and IO lists are split apart, they do not
> need to be protected by the same lock. So in preparation for removal
> of the inode_lock, add new locks for them. The writeback lists are
> only ever accessed in the context of a bdi, so add a per-BDI lock to
> protect manipulations of these lists.
>
> For the inode LRU, introduce a simple global lock to protect it.
> While this could be made per-sb, it is unclear yet as to what is the
> next step for optimising/parallelising reclaim of inodes. Rather
> than optimise now, leave it as a global list and lock until further
> analysis can be done.
>
> Because there will now be a situation where the inode is on
> different lists protected by different locks during the freeing of
> the inode (i.e. not an atomic state transition), we need to ensure
> that we set the I_FREEING state flag before we start removing inodes
> from the IO and LRU lists. This ensures that if we race with other
> threads during freeing, they will notice the I_FREEING flag is set
> and be able to take appropriate action to avoid problems.
>
> Based on a patch originally from Nick Piggin.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/fs-writeback.c | 51 +++++++++++++++++++++++++++++++++++++---
> fs/inode.c | 54 ++++++++++++++++++++++++++++++++++++------
> fs/internal.h | 5 ++++
> include/linux/backing-dev.h | 1 +
> mm/backing-dev.c | 18 ++++++++++++++
> 5 files changed, 117 insertions(+), 12 deletions(-)
>
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 387385b..45046af 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -157,6 +157,18 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi)
> }
>
> /*
> + * Remove the inode from the writeback list it is on.
> + */
> +void inode_wb_list_del(struct inode *inode)
> +{
> + struct backing_dev_info *bdi = inode_to_bdi(inode);
> +
> + spin_lock(&bdi->wb.b_lock);
> + list_del_init(&inode->i_wb_list);
> + spin_unlock(&bdi->wb.b_lock);
> +}
> +
> +/*
> * Redirty an inode: set its when-it-was dirtied timestamp and move it to the
> * furthest end of its superblock's dirty-inode list.
> *
> @@ -169,6 +181,7 @@ static void redirty_tail(struct inode *inode)
> {
> struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
>
> + assert_spin_locked(&wb->b_lock);
> if (!list_empty(&wb->b_dirty)) {
> struct inode *tail;
>
> @@ -186,6 +199,7 @@ static void requeue_io(struct inode *inode)
> {
> struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
>
> + assert_spin_locked(&wb->b_lock);
> list_move(&inode->i_wb_list, &wb->b_more_io);
> }
>
> @@ -269,6 +283,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
> */
> static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
> {
> + assert_spin_locked(&wb->b_lock);
> list_splice_init(&wb->b_more_io, &wb->b_io);
> move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
> }
> @@ -311,6 +326,7 @@ static void inode_wait_for_writeback(struct inode *inode)
> static int
> writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> {
> + struct backing_dev_info *bdi = inode_to_bdi(inode);
> struct address_space *mapping = inode->i_mapping;
> unsigned dirty;
> int ret;
> @@ -330,7 +346,9 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * completed a full scan of b_io.
> */
> if (wbc->sync_mode != WB_SYNC_ALL) {
> + spin_lock(&bdi->wb.b_lock);
> requeue_io(inode);
> + spin_unlock(&bdi->wb.b_lock);
> return 0;
> }
>
> @@ -385,6 +403,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * sometimes bales out without doing anything.
> */
> inode->i_state |= I_DIRTY_PAGES;
> + spin_lock(&bdi->wb.b_lock);
> if (wbc->nr_to_write <= 0) {
> /*
> * slice used up: queue for next turn
> @@ -400,6 +419,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> */
> redirty_tail(inode);
> }
> + spin_unlock(&bdi->wb.b_lock);
> } else if (inode->i_state & I_DIRTY) {
> /*
> * Filesystems can dirty the inode during writeback
> @@ -407,10 +427,12 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * submission or metadata updates after data IO
> * completion.
> */
> + spin_lock(&bdi->wb.b_lock);
> redirty_tail(inode);
> + spin_unlock(&bdi->wb.b_lock);
> } else {
> /* The inode is clean */
> - list_del_init(&inode->i_wb_list);
> + inode_wb_list_del(inode);
> inode_lru_list_add(inode);
> }
> }
> @@ -457,6 +479,7 @@ static bool pin_sb_for_writeback(struct super_block *sb)
> static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> struct writeback_control *wbc, bool only_this_sb)
> {
> + assert_spin_locked(&wb->b_lock);
> while (!list_empty(&wb->b_io)) {
> long pages_skipped;
> struct inode *inode = list_entry(wb->b_io.prev,
> @@ -472,7 +495,6 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> redirty_tail(inode);
> continue;
> }
> -
> /*
> * The inode belongs to a different superblock.
> * Bounce back to the caller to unpin this and
> @@ -481,7 +503,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> return 0;
> }
>
> - if (inode->i_state & (I_NEW | I_WILL_FREE)) {
> + /*
> + * We can see I_FREEING here when the inod isin the process of
s/inod isin/inode is in/
> + * being reclaimed. In that case the freer is waiting on the
> + * wb->b_lock that we currently hold to remove the inode from
> + * the writeback list. So we don't spin on it here, requeue it
> + * and move on to the next inode, which will allow the other
> + * thread to free the inode when we drop the lock.
> + */
> + if (inode->i_state & (I_NEW | I_WILL_FREE | I_FREEING)) {
> requeue_io(inode);
> continue;
> }
> @@ -492,10 +522,11 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> if (inode_dirtied_after(inode, wbc->wb_start))
> return 1;
>
> - BUG_ON(inode->i_state & I_FREEING);
> spin_lock(&inode->i_lock);
> inode->i_ref++;
> spin_unlock(&inode->i_lock);
> + spin_unlock(&wb->b_lock);
> +
> pages_skipped = wbc->pages_skipped;
> writeback_single_inode(inode, wbc);
> if (wbc->pages_skipped != pages_skipped) {
> @@ -503,12 +534,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> * writeback is not making progress due to locked
> * buffers. Skip this inode for now.
> */
> + spin_lock(&wb->b_lock);
> redirty_tail(inode);
> + spin_unlock(&wb->b_lock);
> }
> spin_unlock(&inode_lock);
> iput(inode);
> cond_resched();
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> if (wbc->nr_to_write <= 0) {
> wbc->more_io = 1;
> return 1;
> @@ -528,6 +562,8 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
> if (!wbc->wb_start)
> wbc->wb_start = jiffies; /* livelock avoidance */
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> +
> if (!wbc->for_kupdate || list_empty(&wb->b_io))
> queue_io(wb, wbc->older_than_this);
>
> @@ -546,6 +582,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
> if (ret)
> break;
> }
> + spin_unlock(&wb->b_lock);
> spin_unlock(&inode_lock);
> /* Leave any unwritten inodes on b_io */
> }
> @@ -556,9 +593,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
> WARN_ON(!rwsem_is_locked(&sb->s_umount));
>
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> if (!wbc->for_kupdate || list_empty(&wb->b_io))
> queue_io(wb, wbc->older_than_this);
> writeback_sb_inodes(sb, wb, wbc, true);
> + spin_unlock(&wb->b_lock);
> spin_unlock(&inode_lock);
> }
>
> @@ -671,8 +710,10 @@ static long wb_writeback(struct bdi_writeback *wb,
> */
> spin_lock(&inode_lock);
> if (!list_empty(&wb->b_more_io)) {
> + spin_lock(&wb->b_lock);
> inode = list_entry(wb->b_more_io.prev,
> struct inode, i_wb_list);
> + spin_unlock(&wb->b_lock);
> trace_wbc_writeback_wait(&wbc, wb->bdi);
> inode_wait_for_writeback(inode);
> }
> @@ -985,8 +1026,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
> wakeup_bdi = true;
> }
>
> + spin_lock(&bdi->wb.b_lock);
> inode->dirtied_when = jiffies;
> list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
> + spin_unlock(&bdi->wb.b_lock);
> }
> }
> out:
> diff --git a/fs/inode.c b/fs/inode.c
> index ab65f99..a9ba18a 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -26,6 +26,8 @@
> #include <linux/posix_acl.h>
> #include <linux/bit_spinlock.h>
>
> +#include "internal.h"
> +
> /*
> * Locking rules.
> *
> @@ -35,6 +37,10 @@
> * inode hash table, i_hash
> * sb inode lock protects:
> * s_inodes, i_sb_list
> + * bdi writeback lock protects:
> + * b_io, b_more_io, b_dirty, i_io
s/i_io/i_wb_list/
> + * inode_lru_lock protects:
> + * inode_lru, i_lru
> *
> * Lock orders
> * inode_lock
> @@ -43,7 +49,9 @@
> *
> * inode_lock
> * sb inode lock
> - * inode->i_lock
> + * inode_lru_lock
> + * wb->b_lock
> + * inode->i_lock
> */
> /*
> * This is needed for the following functions:
> @@ -93,6 +101,7 @@ static struct hlist_bl_head *inode_hashtable __read_mostly;
> * allowing for low-overhead inode sync() operations.
> */
> static LIST_HEAD(inode_lru);
> +static DEFINE_SPINLOCK(inode_lru_lock);
>
> /*
> * A simple spinlock to protect the list manipulations.
> @@ -353,20 +362,28 @@ void iref(struct inode *inode)
> }
> EXPORT_SYMBOL_GPL(iref);
>
> +/*
> + * check against I_FREEING as inode writeback completion could race with
> + * setting the I_FREEING and removing the inode from the LRU.
> + */
> void inode_lru_list_add(struct inode *inode)
> {
> - if (list_empty(&inode->i_lru)) {
> + spin_lock(&inode_lru_lock);
> + if (list_empty(&inode->i_lru) && !(inode->i_state & I_FREEING)) {
> list_add(&inode->i_lru, &inode_lru);
> percpu_counter_inc(&nr_inodes_unused);
> }
> + spin_unlock(&inode_lru_lock);
> }
>
> void inode_lru_list_del(struct inode *inode)
> {
> + spin_lock(&inode_lru_lock);
> if (!list_empty(&inode->i_lru)) {
> list_del_init(&inode->i_lru);
> percpu_counter_dec(&nr_inodes_unused);
> }
> + spin_unlock(&inode_lru_lock);
> }
>
> static unsigned long hash(struct super_block *sb, unsigned long hashval)
> @@ -524,8 +541,18 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
> spin_unlock(&inode->i_lock);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
> +
> + /*
> + * move the inode off the IO lists and LRU once
s/IO lists/writeback lists/
> + * I_FREEING is set so that it won't get moved back on
> + * there if it is dirty.
> + */
> + inode_wb_list_del(inode);
> +
> + spin_lock(&inode_lru_lock);
> list_move(&inode->i_lru, dispose);
> percpu_counter_dec(&nr_inodes_unused);
> + spin_unlock(&inode_lru_lock);
> continue;
> }
> spin_unlock(&inode->i_lock);
> @@ -599,6 +626,7 @@ static void prune_icache(int nr_to_scan)
>
> down_read(&iprune_sem);
> spin_lock(&inode_lock);
> + spin_lock(&inode_lru_lock);
> for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
> struct inode *inode;
>
> @@ -629,12 +657,14 @@ static void prune_icache(int nr_to_scan)
> if (inode_has_buffers(inode) || inode->i_data.nrpages) {
> inode->i_ref++;
> spin_unlock(&inode->i_lock);
> + spin_unlock(&inode_lru_lock);
> spin_unlock(&inode_lock);
> if (remove_inode_buffers(inode))
> reap += invalidate_mapping_pages(&inode->i_data,
> 0, -1);
> iput(inode);
> spin_lock(&inode_lock);
> + spin_lock(&inode_lru_lock);
>
> /*
> * if we can't reclaim this inode immediately, give it
> @@ -647,16 +677,24 @@ static void prune_icache(int nr_to_scan)
> }
> } else
> spin_unlock(&inode->i_lock);
> - list_move(&inode->i_lru, &freeable);
> - list_del_init(&inode->i_wb_list);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
> +
> + /*
> + * move the inode off the io lists and lru once
> + * i_freeing is set so that it won't get moved back on
> + * there if it is dirty.
> + */
s/io lists/writeback lists/
s/i_freeing/I_FREEING/
> + inode_wb_list_del(inode);
> +
> + list_move(&inode->i_lru, &freeable);
> percpu_counter_dec(&nr_inodes_unused);
> }
> if (current_is_kswapd())
> __count_vm_events(KSWAPD_INODESTEAL, reap);
> else
> __count_vm_events(PGINODESTEAL, reap);
> + spin_unlock(&inode_lru_lock);
> spin_unlock(&inode_lock);
>
> dispose_list(&freeable);
> @@ -1389,15 +1427,15 @@ static void iput_final(struct inode *inode)
> inode->i_state &= ~I_WILL_FREE;
> __remove_inode_hash(inode);
> }
> - list_del_init(&inode->i_wb_list);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
>
> /*
> - * After we delete the inode from the LRU here, we avoid moving dirty
> - * inodes back onto the LRU now because I_FREEING is set and hence
> - * writeback_single_inode() won't move the inode around.
> + * After we delete the inode from the LRU and IO lists here, we avoid
s/IO lists/writeback lists/
Thanks,
Lin Ming
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 11/18] fs: split locking of inode writeback and LRU lists
@ 2010-10-13 3:26 ` Lin Ming
0 siblings, 0 replies; 50+ messages in thread
From: Lin Ming @ 2010-10-13 3:26 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 8:15 AM, Dave Chinner <david@fromorbit.com> wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Given that the inode LRU and IO lists are split apart, they do not
> need to be protected by the same lock. So in preparation for removal
> of the inode_lock, add new locks for them. The writeback lists are
> only ever accessed in the context of a bdi, so add a per-BDI lock to
> protect manipulations of these lists.
>
> For the inode LRU, introduce a simple global lock to protect it.
> While this could be made per-sb, it is unclear yet as to what is the
> next step for optimising/parallelising reclaim of inodes. Rather
> than optimise now, leave it as a global list and lock until further
> analysis can be done.
>
> Because there will now be a situation where the inode is on
> different lists protected by different locks during the freeing of
> the inode (i.e. not an atomic state transition), we need to ensure
> that we set the I_FREEING state flag before we start removing inodes
> from the IO and LRU lists. This ensures that if we race with other
> threads during freeing, they will notice the I_FREEING flag is set
> and be able to take appropriate action to avoid problems.
>
> Based on a patch originally from Nick Piggin.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/fs-writeback.c | 51 +++++++++++++++++++++++++++++++++++++---
> fs/inode.c | 54 ++++++++++++++++++++++++++++++++++++------
> fs/internal.h | 5 ++++
> include/linux/backing-dev.h | 1 +
> mm/backing-dev.c | 18 ++++++++++++++
> 5 files changed, 117 insertions(+), 12 deletions(-)
>
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 387385b..45046af 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -157,6 +157,18 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi)
> }
>
> /*
> + * Remove the inode from the writeback list it is on.
> + */
> +void inode_wb_list_del(struct inode *inode)
> +{
> + struct backing_dev_info *bdi = inode_to_bdi(inode);
> +
> + spin_lock(&bdi->wb.b_lock);
> + list_del_init(&inode->i_wb_list);
> + spin_unlock(&bdi->wb.b_lock);
> +}
> +
> +/*
> * Redirty an inode: set its when-it-was dirtied timestamp and move it to the
> * furthest end of its superblock's dirty-inode list.
> *
> @@ -169,6 +181,7 @@ static void redirty_tail(struct inode *inode)
> {
> struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
>
> + assert_spin_locked(&wb->b_lock);
> if (!list_empty(&wb->b_dirty)) {
> struct inode *tail;
>
> @@ -186,6 +199,7 @@ static void requeue_io(struct inode *inode)
> {
> struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
>
> + assert_spin_locked(&wb->b_lock);
> list_move(&inode->i_wb_list, &wb->b_more_io);
> }
>
> @@ -269,6 +283,7 @@ static void move_expired_inodes(struct list_head *delaying_queue,
> */
> static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
> {
> + assert_spin_locked(&wb->b_lock);
> list_splice_init(&wb->b_more_io, &wb->b_io);
> move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
> }
> @@ -311,6 +326,7 @@ static void inode_wait_for_writeback(struct inode *inode)
> static int
> writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> {
> + struct backing_dev_info *bdi = inode_to_bdi(inode);
> struct address_space *mapping = inode->i_mapping;
> unsigned dirty;
> int ret;
> @@ -330,7 +346,9 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * completed a full scan of b_io.
> */
> if (wbc->sync_mode != WB_SYNC_ALL) {
> + spin_lock(&bdi->wb.b_lock);
> requeue_io(inode);
> + spin_unlock(&bdi->wb.b_lock);
> return 0;
> }
>
> @@ -385,6 +403,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * sometimes bales out without doing anything.
> */
> inode->i_state |= I_DIRTY_PAGES;
> + spin_lock(&bdi->wb.b_lock);
> if (wbc->nr_to_write <= 0) {
> /*
> * slice used up: queue for next turn
> @@ -400,6 +419,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> */
> redirty_tail(inode);
> }
> + spin_unlock(&bdi->wb.b_lock);
> } else if (inode->i_state & I_DIRTY) {
> /*
> * Filesystems can dirty the inode during writeback
> @@ -407,10 +427,12 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
> * submission or metadata updates after data IO
> * completion.
> */
> + spin_lock(&bdi->wb.b_lock);
> redirty_tail(inode);
> + spin_unlock(&bdi->wb.b_lock);
> } else {
> /* The inode is clean */
> - list_del_init(&inode->i_wb_list);
> + inode_wb_list_del(inode);
> inode_lru_list_add(inode);
> }
> }
> @@ -457,6 +479,7 @@ static bool pin_sb_for_writeback(struct super_block *sb)
> static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> struct writeback_control *wbc, bool only_this_sb)
> {
> + assert_spin_locked(&wb->b_lock);
> while (!list_empty(&wb->b_io)) {
> long pages_skipped;
> struct inode *inode = list_entry(wb->b_io.prev,
> @@ -472,7 +495,6 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> redirty_tail(inode);
> continue;
> }
> -
> /*
> * The inode belongs to a different superblock.
> * Bounce back to the caller to unpin this and
> @@ -481,7 +503,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> return 0;
> }
>
> - if (inode->i_state & (I_NEW | I_WILL_FREE)) {
> + /*
> + * We can see I_FREEING here when the inod isin the process of
s/inod isin/inode is in/
> + * being reclaimed. In that case the freer is waiting on the
> + * wb->b_lock that we currently hold to remove the inode from
> + * the writeback list. So we don't spin on it here, requeue it
> + * and move on to the next inode, which will allow the other
> + * thread to free the inode when we drop the lock.
> + */
> + if (inode->i_state & (I_NEW | I_WILL_FREE | I_FREEING)) {
> requeue_io(inode);
> continue;
> }
> @@ -492,10 +522,11 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> if (inode_dirtied_after(inode, wbc->wb_start))
> return 1;
>
> - BUG_ON(inode->i_state & I_FREEING);
> spin_lock(&inode->i_lock);
> inode->i_ref++;
> spin_unlock(&inode->i_lock);
> + spin_unlock(&wb->b_lock);
> +
> pages_skipped = wbc->pages_skipped;
> writeback_single_inode(inode, wbc);
> if (wbc->pages_skipped != pages_skipped) {
> @@ -503,12 +534,15 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
> * writeback is not making progress due to locked
> * buffers. Skip this inode for now.
> */
> + spin_lock(&wb->b_lock);
> redirty_tail(inode);
> + spin_unlock(&wb->b_lock);
> }
> spin_unlock(&inode_lock);
> iput(inode);
> cond_resched();
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> if (wbc->nr_to_write <= 0) {
> wbc->more_io = 1;
> return 1;
> @@ -528,6 +562,8 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
> if (!wbc->wb_start)
> wbc->wb_start = jiffies; /* livelock avoidance */
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> +
> if (!wbc->for_kupdate || list_empty(&wb->b_io))
> queue_io(wb, wbc->older_than_this);
>
> @@ -546,6 +582,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb,
> if (ret)
> break;
> }
> + spin_unlock(&wb->b_lock);
> spin_unlock(&inode_lock);
> /* Leave any unwritten inodes on b_io */
> }
> @@ -556,9 +593,11 @@ static void __writeback_inodes_sb(struct super_block *sb,
> WARN_ON(!rwsem_is_locked(&sb->s_umount));
>
> spin_lock(&inode_lock);
> + spin_lock(&wb->b_lock);
> if (!wbc->for_kupdate || list_empty(&wb->b_io))
> queue_io(wb, wbc->older_than_this);
> writeback_sb_inodes(sb, wb, wbc, true);
> + spin_unlock(&wb->b_lock);
> spin_unlock(&inode_lock);
> }
>
> @@ -671,8 +710,10 @@ static long wb_writeback(struct bdi_writeback *wb,
> */
> spin_lock(&inode_lock);
> if (!list_empty(&wb->b_more_io)) {
> + spin_lock(&wb->b_lock);
> inode = list_entry(wb->b_more_io.prev,
> struct inode, i_wb_list);
> + spin_unlock(&wb->b_lock);
> trace_wbc_writeback_wait(&wbc, wb->bdi);
> inode_wait_for_writeback(inode);
> }
> @@ -985,8 +1026,10 @@ void __mark_inode_dirty(struct inode *inode, int flags)
> wakeup_bdi = true;
> }
>
> + spin_lock(&bdi->wb.b_lock);
> inode->dirtied_when = jiffies;
> list_move(&inode->i_wb_list, &bdi->wb.b_dirty);
> + spin_unlock(&bdi->wb.b_lock);
> }
> }
> out:
> diff --git a/fs/inode.c b/fs/inode.c
> index ab65f99..a9ba18a 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -26,6 +26,8 @@
> #include <linux/posix_acl.h>
> #include <linux/bit_spinlock.h>
>
> +#include "internal.h"
> +
> /*
> * Locking rules.
> *
> @@ -35,6 +37,10 @@
> * inode hash table, i_hash
> * sb inode lock protects:
> * s_inodes, i_sb_list
> + * bdi writeback lock protects:
> + * b_io, b_more_io, b_dirty, i_io
s/i_io/i_wb_list/
> + * inode_lru_lock protects:
> + * inode_lru, i_lru
> *
> * Lock orders
> * inode_lock
> @@ -43,7 +49,9 @@
> *
> * inode_lock
> * sb inode lock
> - * inode->i_lock
> + * inode_lru_lock
> + * wb->b_lock
> + * inode->i_lock
> */
> /*
> * This is needed for the following functions:
> @@ -93,6 +101,7 @@ static struct hlist_bl_head *inode_hashtable __read_mostly;
> * allowing for low-overhead inode sync() operations.
> */
> static LIST_HEAD(inode_lru);
> +static DEFINE_SPINLOCK(inode_lru_lock);
>
> /*
> * A simple spinlock to protect the list manipulations.
> @@ -353,20 +362,28 @@ void iref(struct inode *inode)
> }
> EXPORT_SYMBOL_GPL(iref);
>
> +/*
> + * check against I_FREEING as inode writeback completion could race with
> + * setting the I_FREEING and removing the inode from the LRU.
> + */
> void inode_lru_list_add(struct inode *inode)
> {
> - if (list_empty(&inode->i_lru)) {
> + spin_lock(&inode_lru_lock);
> + if (list_empty(&inode->i_lru) && !(inode->i_state & I_FREEING)) {
> list_add(&inode->i_lru, &inode_lru);
> percpu_counter_inc(&nr_inodes_unused);
> }
> + spin_unlock(&inode_lru_lock);
> }
>
> void inode_lru_list_del(struct inode *inode)
> {
> + spin_lock(&inode_lru_lock);
> if (!list_empty(&inode->i_lru)) {
> list_del_init(&inode->i_lru);
> percpu_counter_dec(&nr_inodes_unused);
> }
> + spin_unlock(&inode_lru_lock);
> }
>
> static unsigned long hash(struct super_block *sb, unsigned long hashval)
> @@ -524,8 +541,18 @@ static int invalidate_list(struct super_block *sb, struct list_head *head,
> spin_unlock(&inode->i_lock);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
> +
> + /*
> + * move the inode off the IO lists and LRU once
s/IO lists/writeback lists/
> + * I_FREEING is set so that it won't get moved back on
> + * there if it is dirty.
> + */
> + inode_wb_list_del(inode);
> +
> + spin_lock(&inode_lru_lock);
> list_move(&inode->i_lru, dispose);
> percpu_counter_dec(&nr_inodes_unused);
> + spin_unlock(&inode_lru_lock);
> continue;
> }
> spin_unlock(&inode->i_lock);
> @@ -599,6 +626,7 @@ static void prune_icache(int nr_to_scan)
>
> down_read(&iprune_sem);
> spin_lock(&inode_lock);
> + spin_lock(&inode_lru_lock);
> for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
> struct inode *inode;
>
> @@ -629,12 +657,14 @@ static void prune_icache(int nr_to_scan)
> if (inode_has_buffers(inode) || inode->i_data.nrpages) {
> inode->i_ref++;
> spin_unlock(&inode->i_lock);
> + spin_unlock(&inode_lru_lock);
> spin_unlock(&inode_lock);
> if (remove_inode_buffers(inode))
> reap += invalidate_mapping_pages(&inode->i_data,
> 0, -1);
> iput(inode);
> spin_lock(&inode_lock);
> + spin_lock(&inode_lru_lock);
>
> /*
> * if we can't reclaim this inode immediately, give it
> @@ -647,16 +677,24 @@ static void prune_icache(int nr_to_scan)
> }
> } else
> spin_unlock(&inode->i_lock);
> - list_move(&inode->i_lru, &freeable);
> - list_del_init(&inode->i_wb_list);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
> +
> + /*
> + * move the inode off the io lists and lru once
> + * i_freeing is set so that it won't get moved back on
> + * there if it is dirty.
> + */
s/io lists/writeback lists/
s/i_freeing/I_FREEING/
> + inode_wb_list_del(inode);
> +
> + list_move(&inode->i_lru, &freeable);
> percpu_counter_dec(&nr_inodes_unused);
> }
> if (current_is_kswapd())
> __count_vm_events(KSWAPD_INODESTEAL, reap);
> else
> __count_vm_events(PGINODESTEAL, reap);
> + spin_unlock(&inode_lru_lock);
> spin_unlock(&inode_lock);
>
> dispose_list(&freeable);
> @@ -1389,15 +1427,15 @@ static void iput_final(struct inode *inode)
> inode->i_state &= ~I_WILL_FREE;
> __remove_inode_hash(inode);
> }
> - list_del_init(&inode->i_wb_list);
> WARN_ON(inode->i_state & I_NEW);
> inode->i_state |= I_FREEING;
>
> /*
> - * After we delete the inode from the LRU here, we avoid moving dirty
> - * inodes back onto the LRU now because I_FREEING is set and hence
> - * writeback_single_inode() won't move the inode around.
> + * After we delete the inode from the LRU and IO lists here, we avoid
s/IO lists/writeback lists/
Thanks,
Lin Ming
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More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 04/18] fs: inode split IO and LRU lists
2010-10-13 0:15 ` [PATCH 04/18] fs: inode split IO and LRU lists Dave Chinner
@ 2010-10-13 11:31 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 11:31 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 11:15:47AM +1100, Dave Chinner wrote:
> From: Nick Piggin <npiggin@suse.de>
>
> The use of the same inode list structure (inode->i_list) for two
> different list constructs with different lifecycles and purposes
> makes it impossible to separate the locking of the different
> operations. Therefore, to enable the separation of the locking of
> the writeback and reclaim lists, split the inode->i_list into two
> separate lists dedicated to their specific tracking functions.
looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 05/18] fs: Clean up inode reference counting
2010-10-13 0:15 ` [PATCH 05/18] fs: Clean up inode reference counting Dave Chinner
@ 2010-10-13 11:33 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 11:33 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 11:15:48AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Lots of filesystem code open codes the act of getting a reference to
> an inode. Factor the open coded inode lock, increment, unlock into
> a function iref(). This removes most direct external references to
> the inode reference count.
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements
2010-10-13 0:15 ` [PATCH 06/18] exofs: use iput() for inode reference count decrements Dave Chinner
@ 2010-10-13 11:34 ` Christoph Hellwig
2010-10-13 14:49 ` Boaz Harrosh
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 11:34 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
Btw, this looks like a nasty enough bug that it might be worth queing
up for 2.6.36.
On Wed, Oct 13, 2010 at 11:15:49AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Direct modification of the inode reference count is a no-no. Convert
> the exofs decrements to call iput() instead of acting directly on
> i_count.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/exofs/inode.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
> index b631ff3..0fb4d4c 100644
> --- a/fs/exofs/inode.c
> +++ b/fs/exofs/inode.c
> @@ -1101,7 +1101,7 @@ static void create_done(struct exofs_io_state *ios, void *p)
>
> set_obj_created(oi);
>
> - atomic_dec(&inode->i_count);
> + iput(inode);
> wake_up(&oi->i_wq);
> }
>
> @@ -1161,7 +1161,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
> ios->cred = oi->i_cred;
> ret = exofs_sbi_create(ios);
> if (ret) {
> - atomic_dec(&inode->i_count);
> + iput(inode);
> exofs_put_io_state(ios);
> return ERR_PTR(ret);
> }
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
---end quoted text---
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 07/18] fs: rework icount to be a locked variable
2010-10-13 0:15 ` [PATCH 07/18] fs: rework icount to be a locked variable Dave Chinner
@ 2010-10-13 11:36 ` Christoph Hellwig
2010-10-16 0:15 ` Dave Chinner
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 11:36 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> - atomic_inc(&inode->i_count);
> + spin_lock(&inode->i_lock);
> + inode->i_ref++;
> + spin_unlock(&inode->i_lock);
Why isn't this using iref?
> + spin_lock(&inode->i_lock);
> + inode->i_ref++;
> + spin_unlock(&inode->i_lock);
Same here and in a couple of others.
Hmm, I guess because the i_lock later covers other things around.
But it still looks a bit weird.
Except for this stuff the patch looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 09/18] fs: Introduce per-bucket inode hash locks
2010-10-13 0:15 ` [PATCH 09/18] fs: Introduce per-bucket inode hash locks Dave Chinner
@ 2010-10-13 11:41 ` Christoph Hellwig
2010-10-13 15:05 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 11:41 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> #include <linux/mount.h>
> #include <linux/async.h>
> #include <linux/posix_acl.h>
> +#include <linux/bit_spinlock.h>
list_bl.h already includes bit_spinlock.h, so you shouldn't actually
need it here.
> @@ -2154,7 +2154,7 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
> */
> static DEFINE_SPINLOCK(lock);
> spin_lock(&lock);
> - if (hlist_unhashed(&inode->i_hash))
> + if (inode_unhashed(inode))
> __insert_inode_hash(inode,
> inode->i_ino + inode->i_generation);
> spin_unlock(&lock);
That's some amazingly ugly code. Just keeping the hash bucket lock
over the inode_unhashed check and the insert would remove the need for
the weird local spinlock. But that's probably best left for a later
patch.
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 11/18] fs: split locking of inode writeback and LRU lists
2010-10-13 0:15 ` [PATCH 11/18] fs: split locking of inode writeback and LRU lists Dave Chinner
2010-10-13 3:26 ` Lin Ming
@ 2010-10-13 13:18 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 13:18 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> + * We can see I_FREEING here when the inod isin the process of
inode is in
Otherwise looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock
2010-10-13 0:15 ` [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
@ 2010-10-13 13:27 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 13:27 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 11:15:55AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> We currently protect the per-inode state flags with the inode_lock.
> Using a global lock to protect per-object state is overkill when we
> coul duse a per-inode lock to protect the state. Use the
> inode->i_lock for this, and wrap all the state changes and checks
> with the inode->i_lock.
>
> Based on work originally written by Nick Piggin.
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 03/18] fs: Implement lazy LRU updates for inodes.
2010-10-13 0:15 ` [PATCH 03/18] fs: Implement lazy LRU updates for inodes Dave Chinner
@ 2010-10-13 13:32 ` Christoph Hellwig
2010-10-16 0:11 ` Dave Chinner
2010-10-16 7:56 ` Nick Piggin
0 siblings, 2 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 13:32 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> */
> redirty_tail(inode);
> - } else if (atomic_read(&inode->i_count)) {
> - /*
> - * The inode is clean, inuse
> - */
> - list_move(&inode->i_list, &inode_in_use);
> } else {
> - /*
> - * The inode is clean, unused
> - */
> - list_move(&inode->i_list, &inode_unused);
> + /* The inode is clean */
> + list_del_init(&inode->i_list);
> + inode_lru_list_add(inode);
Just noticed this when reviewing a later patch: why do we lose the
i_count check here? There's no point in adding an inode that is still
in use onto the LRU - we'll just remove it again once we find it
during LRU scanning.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 15/18] fs: icache remove inode_lock
2010-10-13 0:15 ` [PATCH 15/18] fs: icache remove inode_lock Dave Chinner
2010-10-13 2:09 ` Dave Chinner
@ 2010-10-13 13:42 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 13:42 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> +[mandatory]
> + inode_lock is gone, replaced by fine grained locks. See fs/inode.c
> +for details of what locks to replace inode_lock with in order to protect
> +particular things. Most of the time, a filesystem only needs ->i_lock, which
> +protects *all* the inode state and its membership on lists that was
> +previously protected with inode_lock.
Actually in general filesystem don't need to know anything of the inode
locking, I suspect we could just drop this blurb. inode_lock wasn't
exported so the only thing that changed for filesystems is that the
atomic i_count counter was replaced by i_ref.
Maybe replace the above with:
[mandatory]
The i_count field in the inode is replaced with i_ref, which is
a regular integer instead of an atomic_t. Filesystems should
not manipulate it directly but use helpers like iref, igrab
and iput.
And btw, Documentation/filesystems/vfs.txt and include/linux/fs.h
still mention i_count, and arch/powerpc/platforms/cell/spufs/file.c
still has a reference to it in code.
> @@ -1261,9 +1234,7 @@ int sync_inode(struct inode *inode, struct writeback_control *wbc)
> {
> int ret;
>
> - spin_lock(&inode_lock);
> ret = writeback_single_inode(inode, wbc);
> - spin_unlock(&inode_lock);
> return ret;
> }
> EXPORT_SYMBOL(sync_inode);
At this point writeback_single_inode and sync_inode are the same.
I'd just rename writeback_single_inode to sync_inode and kill the
wrapper.
> * Lock orders
> - * inode_lock
> * inode hash bucket lock
> * inode->i_lock
> *
> - * inode_lock
> * sb inode lock
> * inode_lru_lock
> * wb->b_lock
reindent?
Otherwise looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal
2010-10-13 0:15 ` [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
@ 2010-10-13 13:51 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 13:51 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> /*
> * Locking rules.
> *
> + * inode->i_lock is *always* the innermost lock.
> + *
shouldn't this be added in an earlier patch?
> @@ -48,8 +50,15 @@
> *
> * sb inode lock
> * inode_lru_lock
> - * wb->b_lock
> - * inode->i_lock
> + * wb->b_lock
> + * inode->i_lock
> + *
> + * wb->b_lock
> + * sb_lock (pin sb for writeback)
> + * inode->i_lock
> + *
> + * inode_lru
> + * inode->i_lock
This doesn't seem to be new in this patch either. Maybe just have
a separate patch to introduce the lock order protection comment in
it's final form instead of the various updates?
> - int busy;
> LIST_HEAD(throw_away);
> + int busy;
>
> down_write(&iprune_sem);
> spin_lock(&sb->s_inodes_lock);
> fsnotify_unmount_inodes(&sb->s_inodes);
> busy = invalidate_list(sb, &sb->s_inodes, &throw_away);
> spin_unlock(&sb->s_inodes_lock);
> + up_write(&iprune_sem);
>
> dispose_list(&throw_away);
> - up_write(&iprune_sem);
I first though this was unsafe. But in the end the lock doesn't
actually need to protect anything here. If we're getting here
from generic_shutdown_super the filesystem is dead already and
thus other calls to invalidate_inodes which need a reference to
the superblock won't arrive here. prune_icache could arrive
here, but I_FREEING will make it skip the inode. So it looks
like the shorter hold time is fine. In fact just cycling through
iprune_sem here would probably be enough.
Even better would be getting rid of the gem by simply doing
per-superblock inode LRUs which require to have a reference on
the superblock and thus avoid reclaim reacing with unmount.
Time to ressurect your patch for it once the lock split up is done.
Otherwise looks good to me.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements
2010-10-13 11:34 ` Christoph Hellwig
@ 2010-10-13 14:49 ` Boaz Harrosh
2010-10-17 1:24 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Boaz Harrosh @ 2010-10-13 14:49 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Dave Chinner, linux-fsdevel, linux-kernel
On 10/13/2010 07:34 AM, Christoph Hellwig wrote:
> Btw, this looks like a nasty enough bug that it might be worth queing
> up for 2.6.36.
>
> On Wed, Oct 13, 2010 at 11:15:49AM +1100, Dave Chinner wrote:
>> From: Dave Chinner <dchinner@redhat.com>
>>
>> Direct modification of the inode reference count is a no-no. Convert
>> the exofs decrements to call iput() instead of acting directly on
>> i_count.
>>
>> Signed-off-by: Dave Chinner <dchinner@redhat.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>> fs/exofs/inode.c | 4 ++--
>> 1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
>> index b631ff3..0fb4d4c 100644
>> --- a/fs/exofs/inode.c
>> +++ b/fs/exofs/inode.c
>> @@ -1101,7 +1101,7 @@ static void create_done(struct exofs_io_state *ios, void *p)
>>
>> set_obj_created(oi);
>>
>> - atomic_dec(&inode->i_count);
>> + iput(inode);
>> wake_up(&oi->i_wq);
>> }
>>
>> @@ -1161,7 +1161,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
>> ios->cred = oi->i_cred;
>> ret = exofs_sbi_create(ios);
>> if (ret) {
>> - atomic_dec(&inode->i_count);
>> + iput(inode);
>> exofs_put_io_state(ios);
>> return ERR_PTR(ret);
>> }
>> --
I suspect it's not a bug but a useless inc/dec because in all my testing
I have not seen an inode leak. Let me investigate if it can be removed.
So I do not think we need it for 2.6.36.
I'll take this patch into my 2.6.37-rcX merge window. It should appear
in linux-next by tomorrow. Hopefully followed by a removal patch later.
Thanks for the catch
Boaz
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
` (17 preceding siblings ...)
2010-10-13 0:16 ` [PATCH 18/18] fs: do not assign default i_ino in new_inode Dave Chinner
@ 2010-10-13 14:51 ` Christoph Hellwig
2010-10-13 15:58 ` Christoph Hellwig
18 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 14:51 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
I've got an interesting oops running xfsqa 030 on this series. Not
sure it's a new one, though:
Entering kdb (current=0xf6ff7270, pid 2274) on processor 0 Oops: (null)
due to oops @ 0xc022de60
<d>Modules linked in:
<c>
<d>Pid: 2274, comm: flush-252:16 Not tainted 2.6.36-rc7+ #399 /Bochs
<d>EIP: 0060:[<c022de60>] EFLAGS: 00010246 CPU: 0 EIP is at redirty_tail+0x90/0xa0
<d>EAX: c0d6cda0 EBX: f54b67fc ECX: 00000000 EDX: 00000000
<d>ESI: f7808c88 EDI: f685a308 EBP: f4109e78 ESP: f4109e70
<d> DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
<0>Process flush-252:16 (pid: 2274, ti=f4108000 task=f6ff7270 task.ti=f4108000)
<0>Stack: f685a2a4 f54b67fc f4109ea4 c022e7df f4109e90 f685a310 f685a318 f4109ed8
<0> 014b6804 f5d29260 f5d29260 f685a2a4 00000000 f4109f18 c022ef78 00000001
<0> f4109ed8 00000000 00000000 c018bb4d f6ff7270 f685a310 f6ff7714 f685a308
<0>Call Trace:
<0> [<c022e7df>] ? writeback_sb_inodes+0x6f/0x1a0
<0> [<c022ef78>] ? wb_writeback+0x118/0x320
<0> [<c018bb4d>] ? local_clock+0x6d/0x70
<0> [<c016f0bc>] ? local_bh_enable_ip+0x6c/0xd0
<0> [<c022f1f5>] ? wb_do_writeback+0x75/0x190
<0> [<c0175d44>] ? del_timer+0x74/0xc0
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 09/18] fs: Introduce per-bucket inode hash locks
2010-10-13 0:15 ` [PATCH 09/18] fs: Introduce per-bucket inode hash locks Dave Chinner
2010-10-13 11:41 ` Christoph Hellwig
@ 2010-10-13 15:05 ` Christoph Hellwig
1 sibling, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 15:05 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
> +
> +/**
> + * hlist_bl_lock - lock a hash list
> + * @h: hash list head to lock
> + */
> +static inline void hlist_bl_lock(struct hlist_bl_head *h)
> +{
> + bit_spin_lock(0, (unsigned long *)h);
> +}
> +
> +/**
> + * hlist_bl_unlock - unlock a hash list
> + * @h: hash list head to unlock
> + */
> +static inline void hlist_bl_unlock(struct hlist_bl_head *h)
> +{
> + __bit_spin_unlock(0, (unsigned long *)h);
> +}
I think the locking helpers should come with the rest of the bl_list
implementation in patch1.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 17/18] fs: split __inode_add_to_list
2010-10-13 0:16 ` [PATCH 17/18] fs: split __inode_add_to_list Dave Chinner
@ 2010-10-13 15:08 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 15:08 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
>
> if (!list_empty(&inode->i_sb_list)) {
> - spin_lock(&inode->i_sb->s_inodes_lock);
> - list_del_init(&inode->i_sb_list);
> - spin_unlock(&inode->i_sb->s_inodes_lock);
> + inode_sb_list_del(inode);
> }
no need to keep the braces here.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 14:51 ` fs: Inode cache scalability V3 Christoph Hellwig
@ 2010-10-13 15:58 ` Christoph Hellwig
2010-10-13 21:46 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 15:58 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
It's 100% reproducible on my kvm VM. The bug is the assert_spin_locked
in redirty_tail. I really can't find a way how we reach it without
d_lock so this really confuses me.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 15:58 ` Christoph Hellwig
@ 2010-10-13 21:46 ` Christoph Hellwig
2010-10-13 23:36 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 21:46 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 11:58:45AM -0400, Christoph Hellwig wrote:
>
> It's 100% reproducible on my kvm VM. The bug is the assert_spin_locked
> in redirty_tail. I really can't find a way how we reach it without
> d_lock so this really confuses me.
We are for some reason getting a block device inode that is on the
dirty list of a bdi that it doesn't point to. Still trying to figure
out how exactly that happens.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 21:46 ` Christoph Hellwig
@ 2010-10-13 23:36 ` Christoph Hellwig
2010-10-13 23:55 ` Dave Chinner
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-13 23:36 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel, axboe
On Wed, Oct 13, 2010 at 05:46:09PM -0400, Christoph Hellwig wrote:
> On Wed, Oct 13, 2010 at 11:58:45AM -0400, Christoph Hellwig wrote:
> >
> > It's 100% reproducible on my kvm VM. The bug is the assert_spin_locked
> > in redirty_tail. I really can't find a way how we reach it without
> > d_lock so this really confuses me.
>
> We are for some reason getting a block device inode that is on the
> dirty list of a bdi that it doesn't point to. Still trying to figure
> out how exactly that happens.
It's because __blkdev_put reset the bdi on the mapping, and bdev inodes
are still special cased to not use s_bdi unlike everybody else. So
we keep switch between different bdis that get locked.
I wonder what's a good workaround for that. Just flushing out all
dirty state of a block device inode on last close would fix, but we'd
still have all the dragons hidden underneath until we finally sort
out the bdi reference mess.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 23:36 ` Christoph Hellwig
@ 2010-10-13 23:55 ` Dave Chinner
2010-10-14 0:06 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-13 23:55 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, linux-kernel, axboe
On Wed, Oct 13, 2010 at 07:36:48PM -0400, Christoph Hellwig wrote:
> On Wed, Oct 13, 2010 at 05:46:09PM -0400, Christoph Hellwig wrote:
> > On Wed, Oct 13, 2010 at 11:58:45AM -0400, Christoph Hellwig wrote:
> > >
> > > It's 100% reproducible on my kvm VM. The bug is the assert_spin_locked
> > > in redirty_tail. I really can't find a way how we reach it without
> > > d_lock so this really confuses me.
> >
> > We are for some reason getting a block device inode that is on the
> > dirty list of a bdi that it doesn't point to. Still trying to figure
> > out how exactly that happens.
>
> It's because __blkdev_put reset the bdi on the mapping, and bdev inodes
> are still special cased to not use s_bdi unlike everybody else. So
> we keep switch between different bdis that get locked.
>
> I wonder what's a good workaround for that. Just flushing out all
> dirty state of a block device inode on last close would fix, but we'd
> still have all the dragons hidden underneath until we finally sort
> out the bdi reference mess.
Perhaps for the moment make __blkdev_put() move the inode onto the
dirty lists for the default bdi when it switches themin the
mapping? e.g. add a "inode_switch_bdi" helper that is only called in
this case?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: fs: Inode cache scalability V3
2010-10-13 23:55 ` Dave Chinner
@ 2010-10-14 0:06 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-14 0:06 UTC (permalink / raw)
To: Dave Chinner; +Cc: Christoph Hellwig, linux-fsdevel, linux-kernel, axboe
On Thu, Oct 14, 2010 at 10:55:52AM +1100, Dave Chinner wrote:
> > I wonder what's a good workaround for that. Just flushing out all
> > dirty state of a block device inode on last close would fix, but we'd
> > still have all the dragons hidden underneath until we finally sort
> > out the bdi reference mess.
>
> Perhaps for the moment make __blkdev_put() move the inode onto the
> dirty lists for the default bdi when it switches them???in the
> mapping? e.g. add a "inode_switch_bdi" helper that is only called in
> this case?
I really hate to sprinkle special cases all over, but given that Linus
decreed he's not going to take larger writeback changes which would be
required to fix this for .37 it'll be hard to avoid this.
Note that it would really be a bdev_inode_switch_bdi - since the move
to using ->s_bdi for all other inodes these hacks aren't required
anymore, it's just the block devices that continue using the bdi
from the mapping that are causing problems.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 03/18] fs: Implement lazy LRU updates for inodes.
2010-10-13 13:32 ` Christoph Hellwig
@ 2010-10-16 0:11 ` Dave Chinner
2010-10-16 7:56 ` Nick Piggin
1 sibling, 0 replies; 50+ messages in thread
From: Dave Chinner @ 2010-10-16 0:11 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 09:32:13AM -0400, Christoph Hellwig wrote:
> > */
> > redirty_tail(inode);
> > - } else if (atomic_read(&inode->i_count)) {
> > - /*
> > - * The inode is clean, inuse
> > - */
> > - list_move(&inode->i_list, &inode_in_use);
> > } else {
> > - /*
> > - * The inode is clean, unused
> > - */
> > - list_move(&inode->i_list, &inode_unused);
> > + /* The inode is clean */
> > + list_del_init(&inode->i_list);
> > + inode_lru_list_add(inode);
>
> Just noticed this when reviewing a later patch: why do we lose the
> i_count check here? There's no point in adding an inode that is still
> in use onto the LRU - we'll just remove it again once we find it
> during LRU scanning.
Good catch. iput_final() moves the inode onto the LRU only if
it is clean, so really only clean, unused inodes need to be added to
the LRU here. Fixed.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 07/18] fs: rework icount to be a locked variable
2010-10-13 11:36 ` Christoph Hellwig
@ 2010-10-16 0:15 ` Dave Chinner
2010-10-16 0:20 ` Dave Chinner
0 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-16 0:15 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 07:36:43AM -0400, Christoph Hellwig wrote:
> > - atomic_inc(&inode->i_count);
> > + spin_lock(&inode->i_lock);
> > + inode->i_ref++;
> > + spin_unlock(&inode->i_lock);
>
> Why isn't this using iref?
>
> > + spin_lock(&inode->i_lock);
> > + inode->i_ref++;
> > + spin_unlock(&inode->i_lock);
>
> Same here and in a couple of others.
>
> Hmm, I guess because the i_lock later covers other things around.
> But it still looks a bit weird.
Ok, I've changed them to iref() calls and convert them to open
coding later on when necessary.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 07/18] fs: rework icount to be a locked variable
2010-10-16 0:15 ` Dave Chinner
@ 2010-10-16 0:20 ` Dave Chinner
2010-10-16 0:23 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Dave Chinner @ 2010-10-16 0:20 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-fsdevel, linux-kernel
On Sat, Oct 16, 2010 at 11:15:33AM +1100, Dave Chinner wrote:
> On Wed, Oct 13, 2010 at 07:36:43AM -0400, Christoph Hellwig wrote:
> > > - atomic_inc(&inode->i_count);
> > > + spin_lock(&inode->i_lock);
> > > + inode->i_ref++;
> > > + spin_unlock(&inode->i_lock);
> >
> > Why isn't this using iref?
> >
> > > + spin_lock(&inode->i_lock);
> > > + inode->i_ref++;
> > > + spin_unlock(&inode->i_lock);
> >
> > Same here and in a couple of others.
> >
> > Hmm, I guess because the i_lock later covers other things around.
> > But it still looks a bit weird.
>
> Ok, I've changed them to iref() calls and convert them to open
> coding later on when necessary.
Oh, NAK that - hit send too soon. I forgot - they're are done that
way because they are under the inode_lock, and iref(), at this point
in the series, takes the inode_lock. So while it looks weird, it has
to stay that way otherwise it deadlocks.....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 07/18] fs: rework icount to be a locked variable
2010-10-16 0:20 ` Dave Chinner
@ 2010-10-16 0:23 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-16 0:23 UTC (permalink / raw)
To: Dave Chinner; +Cc: Christoph Hellwig, linux-fsdevel, linux-kernel
On Sat, Oct 16, 2010 at 11:20:43AM +1100, Dave Chinner wrote:
> Oh, NAK that - hit send too soon. I forgot - they're are done that
> way because they are under the inode_lock, and iref(), at this point
> in the series, takes the inode_lock. So while it looks weird, it has
> to stay that way otherwise it deadlocks.....
Sounds fine anyway. I was just wondering why it was done, and
the later extension of the i_lock coverage is reason enough anyway.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 03/18] fs: Implement lazy LRU updates for inodes.
2010-10-13 13:32 ` Christoph Hellwig
2010-10-16 0:11 ` Dave Chinner
@ 2010-10-16 7:56 ` Nick Piggin
1 sibling, 0 replies; 50+ messages in thread
From: Nick Piggin @ 2010-10-16 7:56 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Dave Chinner, linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 09:32:13AM -0400, Christoph Hellwig wrote:
> > */
> > redirty_tail(inode);
> > - } else if (atomic_read(&inode->i_count)) {
> > - /*
> > - * The inode is clean, inuse
> > - */
> > - list_move(&inode->i_list, &inode_in_use);
> > } else {
> > - /*
> > - * The inode is clean, unused
> > - */
> > - list_move(&inode->i_list, &inode_unused);
> > + /* The inode is clean */
> > + list_del_init(&inode->i_list);
> > + inode_lru_list_add(inode);
>
> Just noticed this when reviewing a later patch: why do we lose the
> i_count check here? There's no point in adding an inode that is still
> in use onto the LRU - we'll just remove it again once we find it
> during LRU scanning.
I did it this way because we're already holding the lock. But with the
inode and lru lists locked seperately in a subsequent patch, it is
better to check the count, I agree.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 18/18] fs: do not assign default i_ino in new_inode
2010-10-13 0:16 ` [PATCH 18/18] fs: do not assign default i_ino in new_inode Dave Chinner
@ 2010-10-16 7:57 ` Nick Piggin
2010-10-16 16:30 ` Christoph Hellwig
0 siblings, 1 reply; 50+ messages in thread
From: Nick Piggin @ 2010-10-16 7:57 UTC (permalink / raw)
To: Dave Chinner; +Cc: linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 11:16:01AM +1100, Dave Chinner wrote:
> From: Christoph Hellwig <hch@lst.de>
>
> Instead of always assigning an increasing inode number in new_inode
> move the call to assign it into those callers that actually need it.
> For now callers that need it is estimated conservatively, that is
> the call is added to all filesystems that do not assign an i_ino
> by themselves. For a few more filesystems we can avoid assigning
> any inode number given that they aren't user visible, and for others
> it could be done lazily when an inode number is actually needed,
> but that's left for later patches.
My patch for this reduces churn by just adding a new function instead.
The last_ino allocator is really fast now, so IMO it was not worth
the churn to go through filesystems; just let them do it.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 18/18] fs: do not assign default i_ino in new_inode
2010-10-16 7:57 ` Nick Piggin
@ 2010-10-16 16:30 ` Christoph Hellwig
0 siblings, 0 replies; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-16 16:30 UTC (permalink / raw)
To: Nick Piggin; +Cc: Dave Chinner, linux-fsdevel, linux-kernel
On Sat, Oct 16, 2010 at 06:57:28PM +1100, Nick Piggin wrote:
> My patch for this reduces churn by just adding a new function instead.
> The last_ino allocator is really fast now, so IMO it was not worth
> the churn to go through filesystems; just let them do it.
See the last comment on this. Allocating an inode and assigning a badly
made up ino for a handfull synthetic filesystems are very different
things. Mixing them up in one function always was a bad idea.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements
2010-10-13 14:49 ` Boaz Harrosh
@ 2010-10-17 1:24 ` Christoph Hellwig
2010-10-24 18:06 ` Boaz Harrosh
0 siblings, 1 reply; 50+ messages in thread
From: Christoph Hellwig @ 2010-10-17 1:24 UTC (permalink / raw)
To: Boaz Harrosh; +Cc: Christoph Hellwig, Dave Chinner, linux-fsdevel, linux-kernel
On Wed, Oct 13, 2010 at 10:49:46AM -0400, Boaz Harrosh wrote:
> I suspect it's not a bug but a useless inc/dec because in all my testing
> I have not seen an inode leak. Let me investigate if it can be removed.
>
> So I do not think we need it for 2.6.36.
>
> I'll take this patch into my 2.6.37-rcX merge window. It should appear
> in linux-next by tomorrow. Hopefully followed by a removal patch later.
It's a very real bug. If an inode goes away in-core before the creation
on the OSD has finished, e.g. by using the drop_cache files the
atomic_dec instead of the iput means you will never call iput_final
and thus leak all ressources associated with the inode, as well as
leaving it on all lists. It's not easy to hit, but very nasty when
it is hit.
Another option to fix it might be to drop the refcount games and just
add a wait for the objection creation in the evict_inode method to
make sure we never remove the inode before the object creation
has finished.
^ permalink raw reply [flat|nested] 50+ messages in thread
* Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements
2010-10-17 1:24 ` Christoph Hellwig
@ 2010-10-24 18:06 ` Boaz Harrosh
0 siblings, 0 replies; 50+ messages in thread
From: Boaz Harrosh @ 2010-10-24 18:06 UTC (permalink / raw)
To: Christoph Hellwig, Dave Chinner, Nick Piggin; +Cc: linux-fsdevel, linux-kernel
On 10/17/2010 03:24 AM, Christoph Hellwig wrote:
> On Wed, Oct 13, 2010 at 10:49:46AM -0400, Boaz Harrosh wrote:
>> I suspect it's not a bug but a useless inc/dec because in all my testing
>> I have not seen an inode leak. Let me investigate if it can be removed.
>>
>> So I do not think we need it for 2.6.36.
>>
>> I'll take this patch into my 2.6.37-rcX merge window. It should appear
>> in linux-next by tomorrow. Hopefully followed by a removal patch later.
>
> It's a very real bug. If an inode goes away in-core before the creation
> on the OSD has finished, e.g. by using the drop_cache files the
> atomic_dec instead of the iput means you will never call iput_final
> and thus leak all ressources associated with the inode, as well as
> leaving it on all lists. It's not easy to hit, but very nasty when
> it is hit.
>
Hi Christoph Dave
As I suspected this fix is not good. For a simple reason, The create_done()
is called from scsi_done() which has irq disabled. So in iput() in the case
evict() is needed we BUG on trying to take the i_mutex.
> Another option to fix it might be to drop the refcount games and just
> add a wait for the objection creation in the evict_inode method to
> make sure we never remove the inode before the object creation
> has finished.
>
On the other hand this solution does work, perfectly. Actually there
was already a "wait for the objection creation" in exofs_evict_inode().
Hence the reason I've never seen an inode leak. Below is the patch I'm
putting in -next for push to 2.6.37 (So there was no bug in exofs after all,
I'm not CC(ing) stable@)
Boaz
---
From: Boaz Harrosh <bharrosh@panasas.com>
Subject: [PATCH] exofs: remove inode->i_count ref/deref in exofs_new_inode/create_done
exofs_new_inode was incrementing the inode->i_count and
decrementing it in create_done, in a bad attempt to make
sure the inode will still be there when asynchronous create_done
finally arrives. This was stupid because iput() was not called,
and if is the final ref, could leak the inode.
However all this is not needed, because at exofs_evict_inode()
we already wait for create_done return by waiting for the
create_object event. Therefore remove the extra ref counting
and just Thicken the comment at exofs_evict_inode() a bit.
(Also use ready made __exofs_wait_obj_created instead of
open-coding it.)
CC: Dave Chinner <dchinner@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
fs/exofs/inode.c | 19 ++++++-------------
1 files changed, 6 insertions(+), 13 deletions(-)
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 0ba9886..31e9164 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1102,7 +1102,6 @@ static void create_done(struct exofs_io_state *ios, void *p)
set_obj_created(oi);
- atomic_dec(&inode->i_count);
wake_up(&oi->i_wq);
}
@@ -1153,17 +1152,11 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
ios->obj.id = exofs_oi_objno(oi);
exofs_make_credential(oi->i_cred, &ios->obj);
- /* increment the refcount so that the inode will still be around when we
- * reach the callback
- */
- atomic_inc(&inode->i_count);
-
ios->done = create_done;
ios->private = inode;
ios->cred = oi->i_cred;
ret = exofs_sbi_create(ios);
if (ret) {
- atomic_dec(&inode->i_count);
exofs_put_io_state(ios);
return ERR_PTR(ret);
}
@@ -1321,12 +1314,12 @@ void exofs_evict_inode(struct inode *inode)
inode->i_size = 0;
end_writeback(inode);
- /* if we are deleting an obj that hasn't been created yet, wait */
- if (!obj_created(oi)) {
- BUG_ON(!obj_2bcreated(oi));
- wait_event(oi->i_wq, obj_created(oi));
- /* ignore the error attempt a remove anyway */
- }
+ /* if we are deleting an obj that hasn't been created yet, wait
+ * This also makes sure that create_done cannot be called with an
+ * already deleted inode.
+ */
+ __exofs_wait_obj_created(oi);
+ /* ignore the error attempt a remove anyway */
/* Now Remove the OSD objects */
ret = exofs_get_io_state(&sbi->layout, &ios);
--
1.7.2.3
^ permalink raw reply related [flat|nested] 50+ messages in thread
end of thread, other threads:[~2010-10-24 18:06 UTC | newest]
Thread overview: 50+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-10-13 0:15 fs: Inode cache scalability V3 Dave Chinner
2010-10-13 0:15 ` [PATCH 01/18] kernel: add bl_list Dave Chinner
2010-10-13 0:15 ` [PATCH 02/18] fs: Convert nr_inodes and nr_unused to per-cpu counters Dave Chinner
2010-10-13 0:15 ` [PATCH 03/18] fs: Implement lazy LRU updates for inodes Dave Chinner
2010-10-13 13:32 ` Christoph Hellwig
2010-10-16 0:11 ` Dave Chinner
2010-10-16 7:56 ` Nick Piggin
2010-10-13 0:15 ` [PATCH 04/18] fs: inode split IO and LRU lists Dave Chinner
2010-10-13 11:31 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 05/18] fs: Clean up inode reference counting Dave Chinner
2010-10-13 11:33 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 06/18] exofs: use iput() for inode reference count decrements Dave Chinner
2010-10-13 11:34 ` Christoph Hellwig
2010-10-13 14:49 ` Boaz Harrosh
2010-10-17 1:24 ` Christoph Hellwig
2010-10-24 18:06 ` Boaz Harrosh
2010-10-13 0:15 ` [PATCH 07/18] fs: rework icount to be a locked variable Dave Chinner
2010-10-13 11:36 ` Christoph Hellwig
2010-10-16 0:15 ` Dave Chinner
2010-10-16 0:20 ` Dave Chinner
2010-10-16 0:23 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 08/18] fs: Factor inode hash operations into functions Dave Chinner
2010-10-13 0:15 ` [PATCH 09/18] fs: Introduce per-bucket inode hash locks Dave Chinner
2010-10-13 11:41 ` Christoph Hellwig
2010-10-13 15:05 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 10/18] fs: add a per-superblock lock for the inode list Dave Chinner
2010-10-13 0:15 ` [PATCH 11/18] fs: split locking of inode writeback and LRU lists Dave Chinner
2010-10-13 3:26 ` Lin Ming
2010-10-13 3:26 ` Lin Ming
2010-10-13 13:18 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 12/18] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
2010-10-13 13:27 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 13/18] fs: introduce a per-cpu last_ino allocator Dave Chinner
2010-10-13 0:15 ` [PATCH 14/18] fs: Make iunique independent of inode_lock Dave Chinner
2010-10-13 0:15 ` [PATCH 15/18] fs: icache remove inode_lock Dave Chinner
2010-10-13 2:09 ` Dave Chinner
2010-10-13 13:42 ` Christoph Hellwig
2010-10-13 0:15 ` [PATCH 16/18] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
2010-10-13 13:51 ` Christoph Hellwig
2010-10-13 0:16 ` [PATCH 17/18] fs: split __inode_add_to_list Dave Chinner
2010-10-13 15:08 ` Christoph Hellwig
2010-10-13 0:16 ` [PATCH 18/18] fs: do not assign default i_ino in new_inode Dave Chinner
2010-10-16 7:57 ` Nick Piggin
2010-10-16 16:30 ` Christoph Hellwig
2010-10-13 14:51 ` fs: Inode cache scalability V3 Christoph Hellwig
2010-10-13 15:58 ` Christoph Hellwig
2010-10-13 21:46 ` Christoph Hellwig
2010-10-13 23:36 ` Christoph Hellwig
2010-10-13 23:55 ` Dave Chinner
2010-10-14 0:06 ` Christoph Hellwig
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