* [PATCH 01/11] netvm: Prevent a stream-specific deadlock
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 02/11] selinux: tag avc cache alloc as non-critical Mel Gorman
` (10 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
It could happen that all !SOCK_MEMALLOC sockets have buffered so
much data that we're over the global rmem limit. This will prevent
SOCK_MEMALLOC buffers from receiving data, which will prevent userspace
from running, which is needed to reduce the buffered data.
Fix this by exempting the SOCK_MEMALLOC sockets from the rmem limit.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
include/net/sock.h | 7 ++++---
net/caif/caif_socket.c | 2 +-
net/core/sock.c | 2 +-
net/ipv4/tcp_input.c | 12 ++++++------
net/sctp/ulpevent.c | 2 +-
5 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index de6ebda..733d614 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1279,12 +1279,13 @@ static inline int sk_wmem_schedule(struct sock *sk, int size)
__sk_mem_schedule(sk, size, SK_MEM_SEND);
}
-static inline int sk_rmem_schedule(struct sock *sk, int size)
+static inline int sk_rmem_schedule(struct sock *sk, struct sk_buff *skb)
{
if (!sk_has_account(sk))
return 1;
- return size <= sk->sk_forward_alloc ||
- __sk_mem_schedule(sk, size, SK_MEM_RECV);
+ return skb->truesize <= sk->sk_forward_alloc ||
+ __sk_mem_schedule(sk, skb->truesize, SK_MEM_RECV) ||
+ skb_pfmemalloc(skb);
}
static inline void sk_mem_reclaim(struct sock *sk)
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 5016fa5..aaf711c 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -142,7 +142,7 @@ static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
err = sk_filter(sk, skb);
if (err)
return err;
- if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
+ if (!sk_rmem_schedule(sk, skb) && rx_flow_is_on(cf_sk)) {
set_rx_flow_off(cf_sk);
if (net_ratelimit())
pr_debug("sending flow OFF due to rmem_schedule\n");
diff --git a/net/core/sock.c b/net/core/sock.c
index 9ad1ed9..4193266 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -391,7 +391,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
if (err)
return err;
- if (!sk_rmem_schedule(sk, skb->truesize)) {
+ if (!sk_rmem_schedule(sk, skb)) {
atomic_inc(&sk->sk_drops);
return -ENOBUFS;
}
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e886e2f..330c097 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4427,19 +4427,19 @@ static void tcp_ofo_queue(struct sock *sk)
static int tcp_prune_ofo_queue(struct sock *sk);
static int tcp_prune_queue(struct sock *sk);
-static inline int tcp_try_rmem_schedule(struct sock *sk, unsigned int size)
+static inline int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb)
{
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
- !sk_rmem_schedule(sk, size)) {
+ !sk_rmem_schedule(sk, skb)) {
if (tcp_prune_queue(sk) < 0)
return -1;
- if (!sk_rmem_schedule(sk, size)) {
+ if (!sk_rmem_schedule(sk, skb)) {
if (!tcp_prune_ofo_queue(sk))
return -1;
- if (!sk_rmem_schedule(sk, size))
+ if (!sk_rmem_schedule(sk, skb))
return -1;
}
}
@@ -4454,7 +4454,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
TCP_ECN_check_ce(tp, skb);
- if (tcp_try_rmem_schedule(sk, skb->truesize)) {
+ if (tcp_try_rmem_schedule(sk, skb)) {
/* TODO: should increment a counter */
__kfree_skb(skb);
return;
@@ -4623,7 +4623,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
if (eaten <= 0) {
queue_and_out:
if (eaten < 0 &&
- tcp_try_rmem_schedule(sk, skb->truesize))
+ tcp_try_rmem_schedule(sk, skb))
goto drop;
skb_set_owner_r(skb, sk);
diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index 8a84017..6c6ed2d 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -702,7 +702,7 @@ struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
if (rx_count >= asoc->base.sk->sk_rcvbuf) {
if ((asoc->base.sk->sk_userlocks & SOCK_RCVBUF_LOCK) ||
- (!sk_rmem_schedule(asoc->base.sk, chunk->skb->truesize)))
+ (!sk_rmem_schedule(asoc->base.sk, chunk->skb)))
goto fail;
}
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 02/11] selinux: tag avc cache alloc as non-critical
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
2012-04-16 12:17 ` [PATCH 01/11] netvm: Prevent a stream-specific deadlock Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 03/11] mm: Methods for teaching filesystems about PG_swapcache pages Mel Gorman
` (9 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
Failing to allocate a cache entry will only harm performance not
correctness. Do not consume valuable reserve pages for something
like that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
security/selinux/avc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 8ee42b2..75c2977 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -280,7 +280,7 @@ static struct avc_node *avc_alloc_node(void)
{
struct avc_node *node;
- node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
+ node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC|__GFP_NOMEMALLOC);
if (!node)
goto out;
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 03/11] mm: Methods for teaching filesystems about PG_swapcache pages
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
2012-04-16 12:17 ` [PATCH 01/11] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-04-16 12:17 ` [PATCH 02/11] selinux: tag avc cache alloc as non-critical Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 04/11] mm: Add support for a filesystem to activate swap files and use direct_IO for writing swap pages Mel Gorman
` (8 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
In order to teach filesystems to handle swap cache pages, three new
page functions are introduced:
pgoff_t page_file_index(struct page *);
loff_t page_file_offset(struct page *);
struct address_space *page_file_mapping(struct page *);
page_file_index() - gives the offset of this page in the file in
PAGE_CACHE_SIZE blocks. Like page->index is for mapped pages, this
function also gives the correct index for PG_swapcache pages.
page_file_offset() - uses page_file_index(), so that it will give
the expected result, even for PG_swapcache pages.
page_file_mapping() - gives the mapping backing the actual page;
that is for swap cache pages it will give swap_file->f_mapping.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
include/linux/mm.h | 25 +++++++++++++++++++++++++
include/linux/pagemap.h | 5 +++++
mm/swapfile.c | 19 +++++++++++++++++++
3 files changed, 49 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d8738a4..3cc96ab 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -803,6 +803,17 @@ static inline void *page_rmapping(struct page *page)
return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
}
+extern struct address_space *__page_file_mapping(struct page *);
+
+static inline
+struct address_space *page_file_mapping(struct page *page)
+{
+ if (unlikely(PageSwapCache(page)))
+ return __page_file_mapping(page);
+
+ return page->mapping;
+}
+
static inline int PageAnon(struct page *page)
{
return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
@@ -819,6 +830,20 @@ static inline pgoff_t page_index(struct page *page)
return page->index;
}
+extern pgoff_t __page_file_index(struct page *page);
+
+/*
+ * Return the file index of the page. Regular pagecache pages use ->index
+ * whereas swapcache pages use swp_offset(->private)
+ */
+static inline pgoff_t page_file_index(struct page *page)
+{
+ if (unlikely(PageSwapCache(page)))
+ return __page_file_index(page);
+
+ return page->index;
+}
+
/*
* Return true if this page is mapped into pagetables.
*/
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index cfaaa69..d4d4bda 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -286,6 +286,11 @@ static inline loff_t page_offset(struct page *page)
return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
}
+static inline loff_t page_file_offset(struct page *page)
+{
+ return ((loff_t)page_file_index(page)) << PAGE_CACHE_SHIFT;
+}
+
extern pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
unsigned long address);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index fafc26d..df5f148 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -31,6 +31,7 @@
#include <linux/memcontrol.h>
#include <linux/poll.h>
#include <linux/oom.h>
+#include <linux/export.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
@@ -2293,6 +2294,24 @@ int swapcache_prepare(swp_entry_t entry)
}
/*
+ * out-of-line __page_file_ methods to avoid include hell.
+ */
+struct address_space *__page_file_mapping(struct page *page)
+{
+ VM_BUG_ON(!PageSwapCache(page));
+ return page_swap_info(page)->swap_file->f_mapping;
+}
+EXPORT_SYMBOL_GPL(__page_file_mapping);
+
+pgoff_t __page_file_index(struct page *page)
+{
+ swp_entry_t swap = { .val = page_private(page) };
+ VM_BUG_ON(!PageSwapCache(page));
+ return swp_offset(swap);
+}
+EXPORT_SYMBOL_GPL(__page_file_index);
+
+/*
* add_swap_count_continuation - called when a swap count is duplicated
* beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's
* page of the original vmalloc'ed swap_map, to hold the continuation count
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 04/11] mm: Add support for a filesystem to activate swap files and use direct_IO for writing swap pages
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (2 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 03/11] mm: Methods for teaching filesystems about PG_swapcache pages Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
[not found] ` <1334578675-23445-5-git-send-email-mgorman-l3A5Bk7waGM@public.gmane.org>
2012-04-16 12:17 ` [PATCH 05/11] mm: swap: Implement generic handler for swap_activate Mel Gorman
` (7 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
Currently swapfiles are managed entirely by the core VM by using ->bmap
to allocate space and write to the blocks directly. This effectively
ensures that the underlying blocks are allocated and avoids the need
for the swap subsystem to locate what physical blocks store offsets
within a file.
If the swap subsystem is to use the filesystem information to locate
the blocks, it is critical that information such as block groups,
block bitmaps and the block descriptor table that map the swap file
were resident in memory. This patch adds address_space_operations that
the VM can call when activating or deactivating swap backed by a file.
int swap_activate(struct file *);
int swap_deactivate(struct file *);
The ->swap_activate() method is used to communicate to the
file that the VM relies on it, and the address_space should take
adequate measures such as reserving space in the underlying device,
reserving memory for mempools and pinning information such as the
block descriptor table in memory. The ->swap_deactivate() method is
called on sys_swapoff() if ->swap_activate() returned success.
After a successful swapfile ->swap_activate, the swapfile
is marked SWP_FILE and swapper_space.a_ops will proxy to
sis->swap_file->f_mappings->a_ops using ->direct_io to write swapcache
pages and ->readpage to read.
It is perfectly possible that direct_IO be used to read the swap
pages but it is an unnecessary complication. Similarly, it is possible
that ->writepage be used instead of direct_io to write the pages but
filesystem developers have stated that calling writepage from the VM
is undesirable for a variety of reasons and using direct_IO opens up
the possibility of writing back batches of swap pages in the future.
[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
Documentation/filesystems/Locking | 13 ++++++++++
Documentation/filesystems/vfs.txt | 12 +++++++++
include/linux/fs.h | 4 +++
include/linux/swap.h | 3 +++
mm/page_io.c | 52 +++++++++++++++++++++++++++++++++++++
mm/swap_state.c | 2 +-
mm/swapfile.c | 30 +++++++++++++++++++--
7 files changed, 113 insertions(+), 3 deletions(-)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 4fca82e..b01c2d7 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -202,6 +202,8 @@ prototypes:
int (*launder_page)(struct page *);
int (*is_partially_uptodate)(struct page *, read_descriptor_t *, unsigned long);
int (*error_remove_page)(struct address_space *, struct page *);
+ int (*swap_activate)(struct file *);
+ int (*swap_deactivate)(struct file *);
locking rules:
All except set_page_dirty and freepage may block
@@ -225,6 +227,8 @@ migratepage: yes (both)
launder_page: yes
is_partially_uptodate: yes
error_remove_page: yes
+swap_activate: no
+swap_deactivate: no
->write_begin(), ->write_end(), ->sync_page() and ->readpage()
may be called from the request handler (/dev/loop).
@@ -326,6 +330,15 @@ cleaned, or an error value if not. Note that in order to prevent the page
getting mapped back in and redirtied, it needs to be kept locked
across the entire operation.
+ ->swap_activate will be called with a non-zero argument on
+files backing (non block device backed) swapfiles. A return value
+of zero indicates success, in which case this file can be used for
+backing swapspace. The swapspace operations will be proxied to the
+address space operations.
+
+ ->swap_deactivate() will be called in the sys_swapoff()
+path after ->swap_activate() returned success.
+
----------------------- file_lock_operations ------------------------------
prototypes:
void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index e916e3d..8058d21 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -581,6 +581,8 @@ struct address_space_operations {
int (*migratepage) (struct page *, struct page *);
int (*launder_page) (struct page *);
int (*error_remove_page) (struct mapping *mapping, struct page *page);
+ int (*swap_activate)(struct file *);
+ int (*swap_deactivate)(struct file *);
};
writepage: called by the VM to write a dirty page to backing store.
@@ -749,6 +751,16 @@ struct address_space_operations {
Setting this implies you deal with pages going away under you,
unless you have them locked or reference counts increased.
+ swap_activate: Called when swapon is used on a file to allocate
+ space if necessary and pin the block lookup information in
+ memory. A return value of zero indicates success,
+ in which case this file can be used to back swapspace. The
+ swapspace operations will be proxied to this address space's
+ ->swap_{out,in} methods.
+
+ swap_deactivate: Called during swapoff on files where swap_activate
+ was successful.
+
The File Object
===============
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8de6755..0dcd1e8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -626,6 +626,10 @@ struct address_space_operations {
int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
unsigned long);
int (*error_remove_page)(struct address_space *, struct page *);
+
+ /* swapfile support */
+ int (*swap_activate)(struct file *file);
+ int (*swap_deactivate)(struct file *file);
};
extern const struct address_space_operations empty_aops;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b1fd5c7..6b40350 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -151,6 +151,7 @@ enum {
SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */
SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */
SWP_BLKDEV = (1 << 6), /* its a block device */
+ SWP_FILE = (1 << 7), /* set after swap_activate success */
/* add others here before... */
SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
};
@@ -316,6 +317,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
/* linux/mm/page_io.c */
extern int swap_readpage(struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
/* linux/mm/swap_state.c */
@@ -351,6 +353,7 @@ extern int swap_type_of(dev_t, sector_t, struct block_device **);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct page *, struct block_device **);
extern sector_t swapdev_block(int, pgoff_t);
+extern struct swap_info_struct *page_swap_info(struct page *);
extern int reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;
diff --git a/mm/page_io.c b/mm/page_io.c
index dc76b4d..2a7a4c1 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -17,6 +17,7 @@
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/swapops.h>
+#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <asm/pgtable.h>
@@ -93,11 +94,38 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
{
struct bio *bio;
int ret = 0, rw = WRITE;
+ struct swap_info_struct *sis = page_swap_info(page);
if (try_to_free_swap(page)) {
unlock_page(page);
goto out;
}
+
+ if (sis->flags & SWP_FILE) {
+ struct kiocb kiocb;
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+ struct iovec iov = {
+ .iov_base = page_address(page),
+ .iov_len = PAGE_SIZE,
+ };
+
+ init_sync_kiocb(&kiocb, swap_file);
+ kiocb.ki_pos = page_file_offset(page);
+ kiocb.ki_left = PAGE_SIZE;
+ kiocb.ki_nbytes = PAGE_SIZE;
+
+ unlock_page(page);
+ ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
+ &kiocb, &iov,
+ kiocb.ki_pos, 1);
+ if (ret == PAGE_SIZE) {
+ count_vm_event(PSWPOUT);
+ ret = 0;
+ }
+ return ret;
+ }
+
bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
if (bio == NULL) {
set_page_dirty(page);
@@ -119,9 +147,21 @@ int swap_readpage(struct page *page)
{
struct bio *bio;
int ret = 0;
+ struct swap_info_struct *sis = page_swap_info(page);
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(PageUptodate(page));
+
+ if (sis->flags & SWP_FILE) {
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+
+ ret = mapping->a_ops->readpage(swap_file, page);
+ if (!ret)
+ count_vm_event(PSWPIN);
+ return ret;
+ }
+
bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
if (bio == NULL) {
unlock_page(page);
@@ -133,3 +173,15 @@ int swap_readpage(struct page *page)
out:
return ret;
}
+
+int swap_set_page_dirty(struct page *page)
+{
+ struct swap_info_struct *sis = page_swap_info(page);
+
+ if (sis->flags & SWP_FILE) {
+ struct address_space *mapping = sis->swap_file->f_mapping;
+ return mapping->a_ops->set_page_dirty(page);
+ } else {
+ return __set_page_dirty_nobuffers(page);
+ }
+}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 9d3dd37..c25b9cf 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -26,7 +26,7 @@
*/
static const struct address_space_operations swap_aops = {
.writepage = swap_writepage,
- .set_page_dirty = __set_page_dirty_nobuffers,
+ .set_page_dirty = swap_set_page_dirty,
.migratepage = migrate_page,
};
diff --git a/mm/swapfile.c b/mm/swapfile.c
index df5f148..fe2ed44 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1342,6 +1342,14 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
list_del(&se->list);
kfree(se);
}
+
+ if (sis->flags & SWP_FILE) {
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+
+ sis->flags &= ~SWP_FILE;
+ mapping->a_ops->swap_deactivate(swap_file);
+ }
}
/*
@@ -1423,7 +1431,9 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
*/
static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
{
- struct inode *inode;
+ struct file *swap_file = sis->swap_file;
+ struct address_space *mapping = swap_file->f_mapping;
+ struct inode *inode = mapping->host;
unsigned blocks_per_page;
unsigned long page_no;
unsigned blkbits;
@@ -1434,13 +1444,22 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
int nr_extents = 0;
int ret;
- inode = sis->swap_file->f_mapping->host;
if (S_ISBLK(inode->i_mode)) {
ret = add_swap_extent(sis, 0, sis->max, 0);
*span = sis->pages;
goto out;
}
+ if (mapping->a_ops->swap_activate) {
+ ret = mapping->a_ops->swap_activate(swap_file);
+ if (!ret) {
+ sis->flags |= SWP_FILE;
+ ret = add_swap_extent(sis, 0, sis->max, 0);
+ *span = sis->pages;
+ }
+ goto out;
+ }
+
blkbits = inode->i_blkbits;
blocks_per_page = PAGE_SIZE >> blkbits;
@@ -2293,6 +2312,13 @@ int swapcache_prepare(swp_entry_t entry)
return __swap_duplicate(entry, SWAP_HAS_CACHE);
}
+struct swap_info_struct *page_swap_info(struct page *page)
+{
+ swp_entry_t swap = { .val = page_private(page) };
+ BUG_ON(!PageSwapCache(page));
+ return swap_info[swp_type(swap)];
+}
+
/*
* out-of-line __page_file_ methods to avoid include hell.
*/
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 05/11] mm: swap: Implement generic handler for swap_activate
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (3 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 04/11] mm: Add support for a filesystem to activate swap files and use direct_IO for writing swap pages Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-05-01 22:57 ` Andrew Morton
2012-04-16 12:17 ` [PATCH 06/11] mm: Add get_kernel_page[s] for pinning of kernel addresses for I/O Mel Gorman
` (6 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
The version of swap_activate introduced is sufficient for swap-over-NFS
but would not provide enough information to implement a generic handler.
This patch shuffles things slightly to ensure the same information is
available for aops->swap_activate() as is available to the core.
No functionality change.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
include/linux/fs.h | 7 ++--
include/linux/swap.h | 5 +++
mm/page_io.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
mm/swapfile.c | 91 +++----------------------------------------------
4 files changed, 107 insertions(+), 88 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0dcd1e8..5a71145 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -587,6 +587,8 @@ typedef struct {
typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
unsigned long, unsigned long);
+struct swap_info_struct;
+
struct address_space_operations {
int (*writepage)(struct page *page, struct writeback_control *wbc);
int (*readpage)(struct file *, struct page *);
@@ -628,8 +630,9 @@ struct address_space_operations {
int (*error_remove_page)(struct address_space *, struct page *);
/* swapfile support */
- int (*swap_activate)(struct file *file);
- int (*swap_deactivate)(struct file *file);
+ int (*swap_activate)(struct swap_info_struct *sis, struct file *file,
+ sector_t *span);
+ void (*swap_deactivate)(struct file *file);
};
extern const struct address_space_operations empty_aops;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 6b40350..4ab2276 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -320,6 +320,11 @@ extern int swap_writepage(struct page *page, struct writeback_control *wbc);
extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
+int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
+ unsigned long nr_pages, sector_t start_block);
+int generic_swapfile_activate(struct swap_info_struct *, struct file *,
+ sector_t *);
+
/* linux/mm/swap_state.c */
extern struct address_space swapper_space;
#define total_swapcache_pages swapper_space.nrpages
diff --git a/mm/page_io.c b/mm/page_io.c
index 2a7a4c1..0a7492c 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -86,6 +86,98 @@ void end_swap_bio_read(struct bio *bio, int err)
bio_put(bio);
}
+int generic_swapfile_activate(struct swap_info_struct *sis,
+ struct file *swap_file,
+ sector_t *span)
+{
+ struct address_space *mapping = swap_file->f_mapping;
+ struct inode *inode = mapping->host;
+ unsigned blocks_per_page;
+ unsigned long page_no;
+ unsigned blkbits;
+ sector_t probe_block;
+ sector_t last_block;
+ sector_t lowest_block = -1;
+ sector_t highest_block = 0;
+ int nr_extents = 0;
+ int ret;
+
+ blkbits = inode->i_blkbits;
+ blocks_per_page = PAGE_SIZE >> blkbits;
+
+ /*
+ * Map all the blocks into the extent list. This code doesn't try
+ * to be very smart.
+ */
+ probe_block = 0;
+ page_no = 0;
+ last_block = i_size_read(inode) >> blkbits;
+ while ((probe_block + blocks_per_page) <= last_block &&
+ page_no < sis->max) {
+ unsigned block_in_page;
+ sector_t first_block;
+
+ first_block = bmap(inode, probe_block);
+ if (first_block == 0)
+ goto bad_bmap;
+
+ /*
+ * It must be PAGE_SIZE aligned on-disk
+ */
+ if (first_block & (blocks_per_page - 1)) {
+ probe_block++;
+ goto reprobe;
+ }
+
+ for (block_in_page = 1; block_in_page < blocks_per_page;
+ block_in_page++) {
+ sector_t block;
+
+ block = bmap(inode, probe_block + block_in_page);
+ if (block == 0)
+ goto bad_bmap;
+ if (block != first_block + block_in_page) {
+ /* Discontiguity */
+ probe_block++;
+ goto reprobe;
+ }
+ }
+
+ first_block >>= (PAGE_SHIFT - blkbits);
+ if (page_no) { /* exclude the header page */
+ if (first_block < lowest_block)
+ lowest_block = first_block;
+ if (first_block > highest_block)
+ highest_block = first_block;
+ }
+
+ /*
+ * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
+ */
+ ret = add_swap_extent(sis, page_no, 1, first_block);
+ if (ret < 0)
+ goto out;
+ nr_extents += ret;
+ page_no++;
+ probe_block += blocks_per_page;
+reprobe:
+ continue;
+ }
+ ret = nr_extents;
+ *span = 1 + highest_block - lowest_block;
+ if (page_no == 0)
+ page_no = 1; /* force Empty message */
+ sis->max = page_no;
+ sis->pages = page_no - 1;
+ sis->highest_bit = page_no - 1;
+out:
+ return ret;
+bad_bmap:
+ printk(KERN_ERR "swapon: swapfile has holes\n");
+ ret = -EINVAL;
+ goto out;
+}
+
/*
* We may have stale swap cache pages in memory: notice
* them here and get rid of the unnecessary final write.
diff --git a/mm/swapfile.c b/mm/swapfile.c
index fe2ed44..80b3415 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1358,7 +1358,7 @@ static void destroy_swap_extents(struct swap_info_struct *sis)
*
* This function rather assumes that it is called in ascending page order.
*/
-static int
+int
add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
unsigned long nr_pages, sector_t start_block)
{
@@ -1434,106 +1434,25 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span)
struct file *swap_file = sis->swap_file;
struct address_space *mapping = swap_file->f_mapping;
struct inode *inode = mapping->host;
- unsigned blocks_per_page;
- unsigned long page_no;
- unsigned blkbits;
- sector_t probe_block;
- sector_t last_block;
- sector_t lowest_block = -1;
- sector_t highest_block = 0;
- int nr_extents = 0;
int ret;
if (S_ISBLK(inode->i_mode)) {
ret = add_swap_extent(sis, 0, sis->max, 0);
*span = sis->pages;
- goto out;
+ return ret;
}
if (mapping->a_ops->swap_activate) {
- ret = mapping->a_ops->swap_activate(swap_file);
+ ret = mapping->a_ops->swap_activate(sis, swap_file, span);
if (!ret) {
sis->flags |= SWP_FILE;
ret = add_swap_extent(sis, 0, sis->max, 0);
*span = sis->pages;
}
- goto out;
+ return ret;
}
- blkbits = inode->i_blkbits;
- blocks_per_page = PAGE_SIZE >> blkbits;
-
- /*
- * Map all the blocks into the extent list. This code doesn't try
- * to be very smart.
- */
- probe_block = 0;
- page_no = 0;
- last_block = i_size_read(inode) >> blkbits;
- while ((probe_block + blocks_per_page) <= last_block &&
- page_no < sis->max) {
- unsigned block_in_page;
- sector_t first_block;
-
- first_block = bmap(inode, probe_block);
- if (first_block == 0)
- goto bad_bmap;
-
- /*
- * It must be PAGE_SIZE aligned on-disk
- */
- if (first_block & (blocks_per_page - 1)) {
- probe_block++;
- goto reprobe;
- }
-
- for (block_in_page = 1; block_in_page < blocks_per_page;
- block_in_page++) {
- sector_t block;
-
- block = bmap(inode, probe_block + block_in_page);
- if (block == 0)
- goto bad_bmap;
- if (block != first_block + block_in_page) {
- /* Discontiguity */
- probe_block++;
- goto reprobe;
- }
- }
-
- first_block >>= (PAGE_SHIFT - blkbits);
- if (page_no) { /* exclude the header page */
- if (first_block < lowest_block)
- lowest_block = first_block;
- if (first_block > highest_block)
- highest_block = first_block;
- }
-
- /*
- * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
- */
- ret = add_swap_extent(sis, page_no, 1, first_block);
- if (ret < 0)
- goto out;
- nr_extents += ret;
- page_no++;
- probe_block += blocks_per_page;
-reprobe:
- continue;
- }
- ret = nr_extents;
- *span = 1 + highest_block - lowest_block;
- if (page_no == 0)
- page_no = 1; /* force Empty message */
- sis->max = page_no;
- sis->pages = page_no - 1;
- sis->highest_bit = page_no - 1;
-out:
- return ret;
-bad_bmap:
- printk(KERN_ERR "swapon: swapfile has holes\n");
- ret = -EINVAL;
- goto out;
+ return generic_swapfile_activate(sis, swap_file, span);
}
static void enable_swap_info(struct swap_info_struct *p, int prio,
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH 05/11] mm: swap: Implement generic handler for swap_activate
2012-04-16 12:17 ` [PATCH 05/11] mm: swap: Implement generic handler for swap_activate Mel Gorman
@ 2012-05-01 22:57 ` Andrew Morton
2012-05-03 14:57 ` Mel Gorman
0 siblings, 1 reply; 22+ messages in thread
From: Andrew Morton @ 2012-05-01 22:57 UTC (permalink / raw)
To: Mel Gorman
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson
On Mon, 16 Apr 2012 13:17:49 +0100
Mel Gorman <mgorman@suse.de> wrote:
> The version of swap_activate introduced is sufficient for swap-over-NFS
> but would not provide enough information to implement a generic handler.
> This patch shuffles things slightly to ensure the same information is
> available for aops->swap_activate() as is available to the core.
>
> No functionality change.
>
> ...
>
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -587,6 +587,8 @@ typedef struct {
> typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
> unsigned long, unsigned long);
>
> +struct swap_info_struct;
Please put forward declarations at top-of-file. To prevent accidental
duplication later on.
> struct address_space_operations {
> int (*writepage)(struct page *page, struct writeback_control *wbc);
> int (*readpage)(struct file *, struct page *);
>
> ...
>
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
Have you tested all this code with CONFIG_SWAP=n?
Have you sought to minimise additional new code when CONFIG_SWAP=n?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 22+ messages in thread* Re: [PATCH 05/11] mm: swap: Implement generic handler for swap_activate
2012-05-01 22:57 ` Andrew Morton
@ 2012-05-03 14:57 ` Mel Gorman
0 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-05-03 14:57 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson
On Tue, May 01, 2012 at 03:57:47PM -0700, Andrew Morton wrote:
> On Mon, 16 Apr 2012 13:17:49 +0100
> Mel Gorman <mgorman@suse.de> wrote:
>
> > The version of swap_activate introduced is sufficient for swap-over-NFS
> > but would not provide enough information to implement a generic handler.
> > This patch shuffles things slightly to ensure the same information is
> > available for aops->swap_activate() as is available to the core.
> >
> > No functionality change.
> >
> > ...
> >
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -587,6 +587,8 @@ typedef struct {
> > typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
> > unsigned long, unsigned long);
> >
> > +struct swap_info_struct;
>
> Please put forward declarations at top-of-file. To prevent accidental
> duplication later on.
>
Done.
> > struct address_space_operations {
> > int (*writepage)(struct page *page, struct writeback_control *wbc);
> > int (*readpage)(struct file *, struct page *);
> >
> > ...
> >
> > --- a/mm/page_io.c
> > +++ b/mm/page_io.c
>
> Have you tested all this code with CONFIG_SWAP=n?
>
Emm, it builds. That counts, right?
> Have you sought to minimise additional new code when CONFIG_SWAP=n?
>
Not specifically, but generic_swapfile_activate() is defined in page_io.c
and that is built only if CONFIG_SWAP=y. Similarly swapon is in
swapfile.c which is only build when swap is enabled.
--
Mel Gorman
SUSE Labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH 06/11] mm: Add get_kernel_page[s] for pinning of kernel addresses for I/O
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (4 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 05/11] mm: swap: Implement generic handler for swap_activate Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 07/11] nfs: teach the NFS client how to treat PG_swapcache pages Mel Gorman
` (5 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
This patch adds two new APIs get_kernel_pages() and get_kernel_page()
that may be used to pin a vector of kernel addresses for IO. The initial
user is expected to be NFS for allowing pages to be written to swap
using aops->direct_IO(). Strictly speaking, swap-over-NFS only needs
to pin one page for IO but it makes sense to express the API in terms
of a vector and add a helper for pinning single pages.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
include/linux/blk_types.h | 2 ++
include/linux/fs.h | 2 ++
include/linux/mm.h | 4 ++++
mm/memory.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 61 insertions(+)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 4053cbd..1e62642 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -150,6 +150,7 @@ enum rq_flag_bits {
__REQ_FLUSH_SEQ, /* request for flush sequence */
__REQ_IO_STAT, /* account I/O stat */
__REQ_MIXED_MERGE, /* merge of different types, fail separately */
+ __REQ_KERNEL, /* direct IO to kernel pages */
__REQ_NR_BITS, /* stops here */
};
@@ -191,5 +192,6 @@ enum rq_flag_bits {
#define REQ_IO_STAT (1 << __REQ_IO_STAT)
#define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
#define REQ_SECURE (1 << __REQ_SECURE)
+#define REQ_KERNEL (1 << __REQ_KERNEL)
#endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5a71145..d8e2504 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -165,6 +165,8 @@ struct inodes_stat_t {
#define READ 0
#define WRITE RW_MASK
#define READA RWA_MASK
+#define KERNEL_READ (READ|REQ_KERNEL)
+#define KERNEL_WRITE (WRITE|REQ_KERNEL)
#define READ_SYNC (READ | REQ_SYNC)
#define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3cc96ab..aa39873 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1023,6 +1023,10 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
struct page **pages, struct vm_area_struct **vmas);
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);
+struct kvec;
+int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
+ struct page **pages);
+int get_kernel_page(unsigned long start, int write, struct page **pages);
struct page *get_dump_page(unsigned long addr);
extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
diff --git a/mm/memory.c b/mm/memory.c
index 6105f47..0bc990e7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1837,6 +1837,59 @@ next_page:
EXPORT_SYMBOL(__get_user_pages);
/*
+ * get_kernel_pages() - pin kernel pages in memory
+ * @kiov: An array of struct kvec structures
+ * @nr_segs: number of segments to pin
+ * @write: pinning for read/write, currently ignored
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_segs long.
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno. Each page returned must be released
+ * with a put_page() call when it is finished with.
+ */
+int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
+ struct page **pages)
+{
+ int seg;
+
+ for (seg = 0; seg < nr_segs; seg++) {
+ if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
+ return seg;
+
+ /* virt_to_page sanity checks the PFN */
+ pages[seg] = virt_to_page(kiov[seg].iov_base);
+ page_cache_get(pages[seg]);
+ }
+
+ return seg;
+}
+EXPORT_SYMBOL_GPL(get_kernel_pages);
+
+/*
+ * get_kernel_page() - pin a kernel page in memory
+ * @start: starting kernel address
+ * @write: pinning for read/write, currently ignored
+ * @pages: array that receives pointer to the page pinned.
+ * Must be at least nr_segs long.
+ *
+ * Returns 1 if page is pinned. If the page was not pinned, returns
+ * -errno. The page returned must be released with a put_page() call
+ * when it is finished with.
+ */
+int get_kernel_page(unsigned long start, int write, struct page **pages)
+{
+ const struct kvec kiov = {
+ .iov_base = (void *)start,
+ .iov_len = PAGE_SIZE
+ };
+
+ return get_kernel_pages(&kiov, 1, write, pages);
+}
+EXPORT_SYMBOL_GPL(get_kernel_page);
+
+/*
* fixup_user_fault() - manually resolve a user page fault
* @tsk: the task_struct to use for page fault accounting, or
* NULL if faults are not to be recorded.
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 07/11] nfs: teach the NFS client how to treat PG_swapcache pages
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (5 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 06/11] mm: Add get_kernel_page[s] for pinning of kernel addresses for I/O Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 08/11] nfs: disable data cache revalidation for swapfiles Mel Gorman
` (4 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
Replace all relevant occurences of page->index and page->mapping in
the NFS client with the new page_file_index() and page_file_mapping()
functions.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
fs/nfs/file.c | 6 +++---
fs/nfs/internal.h | 7 ++++---
fs/nfs/pagelist.c | 4 ++--
fs/nfs/read.c | 6 +++---
fs/nfs/write.c | 40 +++++++++++++++++++++-------------------
5 files changed, 33 insertions(+), 30 deletions(-)
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index aa9b709..6ead5e3 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -434,7 +434,7 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset)
if (offset != 0)
return;
/* Cancel any unstarted writes on this page */
- nfs_wb_page_cancel(page->mapping->host, page);
+ nfs_wb_page_cancel(page_file_mapping(page)->host, page);
nfs_fscache_invalidate_page(page, page->mapping->host);
}
@@ -476,7 +476,7 @@ static int nfs_release_page(struct page *page, gfp_t gfp)
*/
static int nfs_launder_page(struct page *page)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_inode *nfsi = NFS_I(inode);
dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
@@ -525,7 +525,7 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
lock_page(page);
- mapping = page->mapping;
+ mapping = page_file_mapping(page);
if (mapping != dentry->d_inode->i_mapping)
goto out_unlock;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 2476dc69..a7c16f3 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -434,13 +434,14 @@ void nfs_super_set_maxbytes(struct super_block *sb, __u64 maxfilesize)
static inline
unsigned int nfs_page_length(struct page *page)
{
- loff_t i_size = i_size_read(page->mapping->host);
+ loff_t i_size = i_size_read(page_file_mapping(page)->host);
if (i_size > 0) {
+ pgoff_t page_index = page_file_index(page);
pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
- if (page->index < end_index)
+ if (page_index < end_index)
return PAGE_CACHE_SIZE;
- if (page->index == end_index)
+ if (page_index == end_index)
return ((i_size - 1) & ~PAGE_CACHE_MASK) + 1;
}
return 0;
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d21fcea..77aa83e 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -77,11 +77,11 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
atomic_set(&req->wb_complete, 0);
- req->wb_index = page->index;
+ req->wb_index = page_file_index(page);
page_cache_get(page);
BUG_ON(PagePrivate(page));
BUG_ON(!PageLocked(page));
- BUG_ON(page->mapping->host != inode);
+ BUG_ON(page_file_mapping(page)->host != inode);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 9a0e8ef..188da9e 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -548,11 +548,11 @@ static const struct rpc_call_ops nfs_read_full_ops = {
int nfs_readpage(struct file *file, struct page *page)
{
struct nfs_open_context *ctx;
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
int error;
dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
- page, PAGE_CACHE_SIZE, page->index);
+ page, PAGE_CACHE_SIZE, page_file_index(page));
nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
nfs_add_stats(inode, NFSIOS_READPAGES, 1);
@@ -606,7 +606,7 @@ static int
readpage_async_filler(void *data, struct page *page)
{
struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *new;
unsigned int len;
int error;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 2c68818..6a891eb 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -125,7 +125,7 @@ static struct nfs_page *nfs_page_find_request_locked(struct page *page)
static struct nfs_page *nfs_page_find_request(struct page *page)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req = NULL;
spin_lock(&inode->i_lock);
@@ -137,16 +137,16 @@ static struct nfs_page *nfs_page_find_request(struct page *page)
/* Adjust the file length if we're writing beyond the end */
static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
loff_t end, i_size;
pgoff_t end_index;
spin_lock(&inode->i_lock);
i_size = i_size_read(inode);
end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
- if (i_size > 0 && page->index < end_index)
+ if (i_size > 0 && page_file_index(page) < end_index)
goto out;
- end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
+ end = page_file_offset(page) + ((loff_t)offset+count);
if (i_size >= end)
goto out;
i_size_write(inode, end);
@@ -159,7 +159,7 @@ out:
static void nfs_set_pageerror(struct page *page)
{
SetPageError(page);
- nfs_zap_mapping(page->mapping->host, page->mapping);
+ nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
}
/* We can set the PG_uptodate flag if we see that a write request
@@ -200,7 +200,7 @@ static int nfs_set_page_writeback(struct page *page)
int ret = test_set_page_writeback(page);
if (!ret) {
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_server *nfss = NFS_SERVER(inode);
page_cache_get(page);
@@ -215,7 +215,7 @@ static int nfs_set_page_writeback(struct page *page)
static void nfs_end_page_writeback(struct page *page)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_server *nfss = NFS_SERVER(inode);
end_page_writeback(page);
@@ -226,7 +226,7 @@ static void nfs_end_page_writeback(struct page *page)
static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req;
int ret;
@@ -287,13 +287,13 @@ out:
static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
int ret;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
- nfs_pageio_cond_complete(pgio, page->index);
+ nfs_pageio_cond_complete(pgio, page_file_index(page));
ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
if (ret == -EAGAIN) {
redirty_page_for_writepage(wbc, page);
@@ -310,7 +310,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
struct nfs_pageio_descriptor pgio;
int err;
- nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
+ nfs_pageio_init_write(&pgio, page_file_mapping(page)->host,
+ wb_priority(wbc));
err = nfs_do_writepage(page, wbc, &pgio);
nfs_pageio_complete(&pgio);
if (err < 0)
@@ -441,7 +442,8 @@ nfs_request_add_commit_list(struct nfs_page *req, struct list_head *head)
NFS_I(inode)->ncommit++;
spin_unlock(&inode->i_lock);
inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
- inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
+ inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
+ BDI_RECLAIMABLE);
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
}
EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
@@ -486,7 +488,7 @@ static void
nfs_clear_page_commit(struct page *page)
{
dec_zone_page_state(page, NR_UNSTABLE_NFS);
- dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
+ dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE);
}
static void
@@ -702,7 +704,7 @@ out_err:
static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
struct page *page, unsigned int offset, unsigned int bytes)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req;
req = nfs_try_to_update_request(inode, page, offset, bytes);
@@ -755,7 +757,7 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
nfs_release_request(req);
if (!do_flush)
return 0;
- status = nfs_wb_page(page->mapping->host, page);
+ status = nfs_wb_page(page_file_mapping(page)->host, page);
} while (status == 0);
return status;
}
@@ -781,7 +783,7 @@ int nfs_updatepage(struct file *file, struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_open_context *ctx = nfs_file_open_context(file);
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
int status = 0;
nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
@@ -789,7 +791,7 @@ int nfs_updatepage(struct file *file, struct page *page,
dprintk("NFS: nfs_updatepage(%s/%s %d@%lld)\n",
file->f_path.dentry->d_parent->d_name.name,
file->f_path.dentry->d_name.name, count,
- (long long)(page_offset(page) + offset));
+ (long long)(page_file_offset(page) + offset));
/* If we're not using byte range locks, and we know the page
* is up to date, it may be more efficient to extend the write
@@ -1149,7 +1151,7 @@ static void nfs_writeback_release_partial(void *calldata)
}
if (nfs_write_need_commit(data)) {
- struct inode *inode = page->mapping->host;
+ struct inode *inode = page_file_mapping(page)->host;
spin_lock(&inode->i_lock);
if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
@@ -1441,7 +1443,7 @@ void nfs_retry_commit(struct list_head *page_list,
nfs_list_remove_request(req);
nfs_mark_request_commit(req, lseg);
dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
- dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+ dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
BDI_RECLAIMABLE);
nfs_unlock_request(req);
}
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 08/11] nfs: disable data cache revalidation for swapfiles
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (6 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 07/11] nfs: teach the NFS client how to treat PG_swapcache pages Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 13:10 ` Fred Isaman
2012-04-16 12:17 ` [PATCH 09/11] nfs: enable swap on NFS Mel Gorman
` (3 subsequent siblings)
11 siblings, 1 reply; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
The VM does not like PG_private set on PG_swapcache pages. As suggested
by Trond in http://lkml.org/lkml/2006/8/25/348, this patch disables
NFS data cache revalidation on swap files. as it does not make
sense to have other clients change the file while it is being used as
swap. This avoids setting PG_private on swap pages, since there ought
to be no further races with invalidate_inode_pages2() to deal with.
Since we cannot set PG_private we cannot use page->private which
is already used by PG_swapcache pages to store the nfs_page. Thus
augment the new nfs_page_find_request logic.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
fs/nfs/inode.c | 6 ++++++
fs/nfs/write.c | 51 +++++++++++++++++++++++++++++++++++++--------------
2 files changed, 43 insertions(+), 14 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e8bbfa5..af43ef6 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -880,6 +880,12 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
struct nfs_inode *nfsi = NFS_I(inode);
int ret = 0;
+ /*
+ * swapfiles are not supposed to be shared.
+ */
+ if (IS_SWAPFILE(inode))
+ goto out;
+
if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
|| nfs_attribute_cache_expired(inode)
|| NFS_STALE(inode)) {
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 6a891eb..eea4ec0 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -111,15 +111,30 @@ static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
}
-static struct nfs_page *nfs_page_find_request_locked(struct page *page)
+static struct nfs_page *
+nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
{
struct nfs_page *req = NULL;
- if (PagePrivate(page)) {
+ if (PagePrivate(page))
req = (struct nfs_page *)page_private(page);
- if (req != NULL)
- kref_get(&req->wb_kref);
+ else if (unlikely(PageSwapCache(page))) {
+ struct nfs_page *freq, *t;
+
+ /* Linearly search the commit list for the correct req */
+ list_for_each_entry_safe(freq, t, &nfsi->commit_list, wb_list) {
+ if (freq->wb_page == page) {
+ req = freq;
+ break;
+ }
+ }
+
+ BUG_ON(req == NULL);
}
+
+ if (req)
+ kref_get(&req->wb_kref);
+
return req;
}
@@ -129,7 +144,7 @@ static struct nfs_page *nfs_page_find_request(struct page *page)
struct nfs_page *req = NULL;
spin_lock(&inode->i_lock);
- req = nfs_page_find_request_locked(page);
+ req = nfs_page_find_request_locked(NFS_I(inode), page);
spin_unlock(&inode->i_lock);
return req;
}
@@ -232,7 +247,7 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblo
spin_lock(&inode->i_lock);
for (;;) {
- req = nfs_page_find_request_locked(page);
+ req = nfs_page_find_request_locked(NFS_I(inode), page);
if (req == NULL)
break;
if (nfs_lock_request_dontget(req))
@@ -385,9 +400,15 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
spin_lock(&inode->i_lock);
if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
inode->i_version++;
- set_bit(PG_MAPPED, &req->wb_flags);
- SetPagePrivate(req->wb_page);
- set_page_private(req->wb_page, (unsigned long)req);
+ /*
+ * Swap-space should not get truncated. Hence no need to plug the race
+ * with invalidate/truncate.
+ */
+ if (likely(!PageSwapCache(req->wb_page))) {
+ set_bit(PG_MAPPED, &req->wb_flags);
+ SetPagePrivate(req->wb_page);
+ set_page_private(req->wb_page, (unsigned long)req);
+ }
nfsi->npages++;
kref_get(&req->wb_kref);
spin_unlock(&inode->i_lock);
@@ -404,9 +425,11 @@ static void nfs_inode_remove_request(struct nfs_page *req)
BUG_ON (!NFS_WBACK_BUSY(req));
spin_lock(&inode->i_lock);
- set_page_private(req->wb_page, 0);
- ClearPagePrivate(req->wb_page);
- clear_bit(PG_MAPPED, &req->wb_flags);
+ if (likely(!PageSwapCache(req->wb_page))) {
+ set_page_private(req->wb_page, 0);
+ ClearPagePrivate(req->wb_page);
+ clear_bit(PG_MAPPED, &req->wb_flags);
+ }
nfsi->npages--;
spin_unlock(&inode->i_lock);
nfs_release_request(req);
@@ -646,7 +669,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
spin_lock(&inode->i_lock);
for (;;) {
- req = nfs_page_find_request_locked(page);
+ req = nfs_page_find_request_locked(NFS_I(inode), page);
if (req == NULL)
goto out_unlock;
@@ -1690,7 +1713,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
*/
int nfs_wb_page(struct inode *inode, struct page *page)
{
- loff_t range_start = page_offset(page);
+ loff_t range_start = page_file_offset(page);
loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH 08/11] nfs: disable data cache revalidation for swapfiles
2012-04-16 12:17 ` [PATCH 08/11] nfs: disable data cache revalidation for swapfiles Mel Gorman
@ 2012-04-16 13:10 ` Fred Isaman
[not found] ` <CADnza444dTr=JEtqpL5wxHRNkEc7vBz1qq9TL7Z+5h749vNawg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
0 siblings, 1 reply; 22+ messages in thread
From: Fred Isaman @ 2012-04-16 13:10 UTC (permalink / raw)
To: Mel Gorman
Cc: Andrew Morton, Linux-MM, Linux-Netdev, Linux-NFS, LKML,
David Miller, Trond Myklebust, Neil Brown, Christoph Hellwig,
Peter Zijlstra, Mike Christie, Eric B Munson
On Mon, Apr 16, 2012 at 8:17 AM, Mel Gorman <mgorman@suse.de> wrote:
> The VM does not like PG_private set on PG_swapcache pages. As suggested
> by Trond in http://lkml.org/lkml/2006/8/25/348, this patch disables
> NFS data cache revalidation on swap files. as it does not make
> sense to have other clients change the file while it is being used as
> swap. This avoids setting PG_private on swap pages, since there ought
> to be no further races with invalidate_inode_pages2() to deal with.
>
> Since we cannot set PG_private we cannot use page->private which
> is already used by PG_swapcache pages to store the nfs_page. Thus
> augment the new nfs_page_find_request logic.
>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> ---
> fs/nfs/inode.c | 6 ++++++
> fs/nfs/write.c | 51 +++++++++++++++++++++++++++++++++++++--------------
> 2 files changed, 43 insertions(+), 14 deletions(-)
>
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index e8bbfa5..af43ef6 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -880,6 +880,12 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
> struct nfs_inode *nfsi = NFS_I(inode);
> int ret = 0;
>
> + /*
> + * swapfiles are not supposed to be shared.
> + */
> + if (IS_SWAPFILE(inode))
> + goto out;
> +
> if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
> || nfs_attribute_cache_expired(inode)
> || NFS_STALE(inode)) {
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index 6a891eb..eea4ec0 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -111,15 +111,30 @@ static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
> set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
> }
>
> -static struct nfs_page *nfs_page_find_request_locked(struct page *page)
> +static struct nfs_page *
> +nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
> {
> struct nfs_page *req = NULL;
>
> - if (PagePrivate(page)) {
> + if (PagePrivate(page))
> req = (struct nfs_page *)page_private(page);
> - if (req != NULL)
> - kref_get(&req->wb_kref);
> + else if (unlikely(PageSwapCache(page))) {
> + struct nfs_page *freq, *t;
> +
> + /* Linearly search the commit list for the correct req */
> + list_for_each_entry_safe(freq, t, &nfsi->commit_list, wb_list) {
> + if (freq->wb_page == page) {
> + req = freq;
> + break;
> + }
> + }
> +
> + BUG_ON(req == NULL);
I suspect I am missing something, but why is it guaranteed that the
req is on the commit list?
Fred
> }
> +
> + if (req)
> + kref_get(&req->wb_kref);
> +
> return req;
> }
>
> @@ -129,7 +144,7 @@ static struct nfs_page *nfs_page_find_request(struct page *page)
> struct nfs_page *req = NULL;
>
> spin_lock(&inode->i_lock);
> - req = nfs_page_find_request_locked(page);
> + req = nfs_page_find_request_locked(NFS_I(inode), page);
> spin_unlock(&inode->i_lock);
> return req;
> }
> @@ -232,7 +247,7 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblo
>
> spin_lock(&inode->i_lock);
> for (;;) {
> - req = nfs_page_find_request_locked(page);
> + req = nfs_page_find_request_locked(NFS_I(inode), page);
> if (req == NULL)
> break;
> if (nfs_lock_request_dontget(req))
> @@ -385,9 +400,15 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
> spin_lock(&inode->i_lock);
> if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
> inode->i_version++;
> - set_bit(PG_MAPPED, &req->wb_flags);
> - SetPagePrivate(req->wb_page);
> - set_page_private(req->wb_page, (unsigned long)req);
> + /*
> + * Swap-space should not get truncated. Hence no need to plug the race
> + * with invalidate/truncate.
> + */
> + if (likely(!PageSwapCache(req->wb_page))) {
> + set_bit(PG_MAPPED, &req->wb_flags);
> + SetPagePrivate(req->wb_page);
> + set_page_private(req->wb_page, (unsigned long)req);
> + }
> nfsi->npages++;
> kref_get(&req->wb_kref);
> spin_unlock(&inode->i_lock);
> @@ -404,9 +425,11 @@ static void nfs_inode_remove_request(struct nfs_page *req)
> BUG_ON (!NFS_WBACK_BUSY(req));
>
> spin_lock(&inode->i_lock);
> - set_page_private(req->wb_page, 0);
> - ClearPagePrivate(req->wb_page);
> - clear_bit(PG_MAPPED, &req->wb_flags);
> + if (likely(!PageSwapCache(req->wb_page))) {
> + set_page_private(req->wb_page, 0);
> + ClearPagePrivate(req->wb_page);
> + clear_bit(PG_MAPPED, &req->wb_flags);
> + }
> nfsi->npages--;
> spin_unlock(&inode->i_lock);
> nfs_release_request(req);
> @@ -646,7 +669,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
> spin_lock(&inode->i_lock);
>
> for (;;) {
> - req = nfs_page_find_request_locked(page);
> + req = nfs_page_find_request_locked(NFS_I(inode), page);
> if (req == NULL)
> goto out_unlock;
>
> @@ -1690,7 +1713,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
> */
> int nfs_wb_page(struct inode *inode, struct page *page)
> {
> - loff_t range_start = page_offset(page);
> + loff_t range_start = page_file_offset(page);
> loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
> struct writeback_control wbc = {
> .sync_mode = WB_SYNC_ALL,
> --
> 1.7.9.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH 09/11] nfs: enable swap on NFS
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (7 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 08/11] nfs: disable data cache revalidation for swapfiles Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 10/11] nfs: Prevent page allocator recursions with swap over NFS Mel Gorman
` (2 subsequent siblings)
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
Implement the new swapfile a_ops for NFS and hook up ->direct_IO. This
will set the NFS socket to SOCK_MEMALLOC and run socket reconnect
under PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the
protocol ->connect() method.
PF_MEMALLOC should allow the allocation of struct socket and related
objects and the early (re)setting of SOCK_MEMALLOC should allow us
to receive the packets required for the TCP connection buildup.
[dfeng@redhat.com: Fix handling of multiple swap files]
[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
fs/nfs/Kconfig | 8 ++++
fs/nfs/direct.c | 94 +++++++++++++++++++++++++++++--------------
fs/nfs/file.c | 22 +++++++++-
include/linux/nfs_fs.h | 4 +-
include/linux/sunrpc/xprt.h | 3 ++
net/sunrpc/Kconfig | 5 +++
net/sunrpc/clnt.c | 2 +
net/sunrpc/sched.c | 7 +++-
net/sunrpc/xprtsock.c | 53 ++++++++++++++++++++++++
9 files changed, 161 insertions(+), 37 deletions(-)
diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig
index 2a0e6c5..ff93d0c 100644
--- a/fs/nfs/Kconfig
+++ b/fs/nfs/Kconfig
@@ -75,6 +75,14 @@ config NFS_V4
If unsure, say Y.
+config NFS_SWAP
+ bool "Provide swap over NFS support"
+ default n
+ depends on NFS_FS
+ select SUNRPC_SWAP
+ help
+ This option enables swapon to work on files located on NFS mounts.
+
config NFS_V4_1
bool "NFS client support for NFSv4.1 (EXPERIMENTAL)"
depends on NFS_FS && NFS_V4 && EXPERIMENTAL
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 481be7f..2ef7395 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -111,17 +111,28 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
* @nr_segs: size of iovec array
*
* The presence of this routine in the address space ops vector means
- * the NFS client supports direct I/O. However, we shunt off direct
- * read and write requests before the VFS gets them, so this method
- * should never be called.
+ * the NFS client supports direct I/O. However, for most direct IO, we
+ * shunt off direct read and write requests before the VFS gets them,
+ * so this method is only ever called for swap.
*/
ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
{
+#ifndef CONFIG_NFS_SWAP
dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
iocb->ki_filp->f_path.dentry->d_name.name,
(long long) pos, nr_segs);
return -EINVAL;
+#else
+ VM_BUG_ON(iocb->ki_left != PAGE_SIZE);
+ VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);
+
+ if (rw == READ || rw == KERNEL_READ)
+ return nfs_file_direct_read(iocb, iov, nr_segs, pos,
+ rw == READ ? true : false);
+ return nfs_file_direct_write(iocb, iov, nr_segs, pos,
+ rw == WRITE ? true : false);
+#endif /* CONFIG_NFS_SWAP */
}
static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count)
@@ -278,7 +289,7 @@ static const struct rpc_call_ops nfs_read_direct_ops = {
*/
static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
const struct iovec *iov,
- loff_t pos)
+ loff_t pos, bool uio)
{
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
@@ -312,13 +323,22 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
if (unlikely(!data))
break;
- down_read(¤t->mm->mmap_sem);
- result = get_user_pages(current, current->mm, user_addr,
- data->npages, 1, 0, data->pagevec, NULL);
- up_read(¤t->mm->mmap_sem);
- if (result < 0) {
- nfs_readdata_free(data);
- break;
+ if (uio) {
+ down_read(¤t->mm->mmap_sem);
+ result = get_user_pages(current, current->mm, user_addr,
+ data->npages, 1, 0, data->pagevec, NULL);
+ up_read(¤t->mm->mmap_sem);
+ if (result < 0) {
+ nfs_readdata_free(data);
+ break;
+ }
+ } else {
+ WARN_ON(data->npages != 1);
+ result = get_kernel_page(user_addr, 1, data->pagevec);
+ if (WARN_ON(result != 1)) {
+ nfs_readdata_free(data);
+ break;
+ }
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
@@ -386,7 +406,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
const struct iovec *iov,
unsigned long nr_segs,
- loff_t pos)
+ loff_t pos, bool uio)
{
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
@@ -396,7 +416,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
- result = nfs_direct_read_schedule_segment(dreq, vec, pos);
+ result = nfs_direct_read_schedule_segment(dreq, vec, pos, uio);
if (result < 0)
break;
requested_bytes += result;
@@ -420,7 +440,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
}
static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+ unsigned long nr_segs, loff_t pos, bool uio)
{
ssize_t result = -ENOMEM;
struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -438,7 +458,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
- result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos);
+ result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);
if (!result)
result = nfs_direct_wait(dreq);
out_release:
@@ -705,7 +725,8 @@ static const struct rpc_call_ops nfs_write_direct_ops = {
*/
static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
const struct iovec *iov,
- loff_t pos, int sync)
+ loff_t pos, int sync,
+ bool uio)
{
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->dentry->d_inode;
@@ -739,13 +760,22 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
if (unlikely(!data))
break;
- down_read(¤t->mm->mmap_sem);
- result = get_user_pages(current, current->mm, user_addr,
- data->npages, 0, 0, data->pagevec, NULL);
- up_read(¤t->mm->mmap_sem);
- if (result < 0) {
- nfs_writedata_free(data);
- break;
+ if (uio) {
+ down_read(¤t->mm->mmap_sem);
+ result = get_user_pages(current, current->mm, user_addr,
+ data->npages, 0, 0, data->pagevec, NULL);
+ up_read(¤t->mm->mmap_sem);
+ if (result < 0) {
+ nfs_writedata_free(data);
+ break;
+ }
+ } else {
+ WARN_ON(data->npages != 1);
+ result = get_kernel_page(user_addr, 0, data->pagevec);
+ if (WARN_ON(result != 1)) {
+ nfs_writedata_free(data);
+ break;
+ }
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
@@ -817,7 +847,8 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
const struct iovec *iov,
unsigned long nr_segs,
- loff_t pos, int sync)
+ loff_t pos, int sync,
+ bool uio)
{
ssize_t result = 0;
size_t requested_bytes = 0;
@@ -828,7 +859,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
result = nfs_direct_write_schedule_segment(dreq, vec,
- pos, sync);
+ pos, sync, uio);
if (result < 0)
break;
requested_bytes += result;
@@ -853,7 +884,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos,
- size_t count)
+ size_t count, bool uio)
{
ssize_t result = -ENOMEM;
struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -877,7 +908,8 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
- result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, sync);
+ result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos,
+ sync, uio);
if (!result)
result = nfs_direct_wait(dreq);
out_release:
@@ -908,7 +940,7 @@ out:
* cache.
*/
ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+ unsigned long nr_segs, loff_t pos, bool uio)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
@@ -933,7 +965,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
task_io_account_read(count);
- retval = nfs_direct_read(iocb, iov, nr_segs, pos);
+ retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio);
if (retval > 0)
iocb->ki_pos = pos + retval;
@@ -964,7 +996,7 @@ out:
* is no atomic O_APPEND write facility in the NFS protocol.
*/
ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+ unsigned long nr_segs, loff_t pos, bool uio)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
@@ -996,7 +1028,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
task_io_account_write(count);
- retval = nfs_direct_write(iocb, iov, nr_segs, pos, count);
+ retval = nfs_direct_write(iocb, iov, nr_segs, pos, count, uio);
if (retval > 0)
iocb->ki_pos = pos + retval;
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 6ead5e3..0e330f2 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -187,7 +187,7 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
ssize_t result;
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_read(iocb, iov, nr_segs, pos);
+ return nfs_file_direct_read(iocb, iov, nr_segs, pos, true);
dprintk("NFS: read(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
@@ -486,6 +486,20 @@ static int nfs_launder_page(struct page *page)
return nfs_wb_page(inode, page);
}
+#ifdef CONFIG_NFS_SWAP
+static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
+ sector_t *span)
+{
+ *span = sis->pages;
+ return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 1);
+}
+
+static void nfs_swap_deactivate(struct file *file)
+{
+ xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 0);
+}
+#endif
+
const struct address_space_operations nfs_file_aops = {
.readpage = nfs_readpage,
.readpages = nfs_readpages,
@@ -500,6 +514,10 @@ const struct address_space_operations nfs_file_aops = {
.migratepage = nfs_migrate_page,
.launder_page = nfs_launder_page,
.error_remove_page = generic_error_remove_page,
+#ifdef CONFIG_NFS_SWAP
+ .swap_activate = nfs_swap_activate,
+ .swap_deactivate = nfs_swap_deactivate,
+#endif
};
/*
@@ -574,7 +592,7 @@ static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
size_t count = iov_length(iov, nr_segs);
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_write(iocb, iov, nr_segs, pos);
+ return nfs_file_direct_write(iocb, iov, nr_segs, pos, true);
dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 52a1bdb..1f4efab 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -481,10 +481,10 @@ extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t,
unsigned long);
extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
const struct iovec *iov, unsigned long nr_segs,
- loff_t pos);
+ loff_t pos, bool uio);
extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
const struct iovec *iov, unsigned long nr_segs,
- loff_t pos);
+ loff_t pos, bool uio);
/*
* linux/fs/nfs/dir.c
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 77d278d..cff40aa 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -174,6 +174,8 @@ struct rpc_xprt {
unsigned long state; /* transport state */
unsigned char shutdown : 1, /* being shut down */
resvport : 1; /* use a reserved port */
+ unsigned int swapper; /* we're swapping over this
+ transport */
unsigned int bind_index; /* bind function index */
/*
@@ -316,6 +318,7 @@ void xprt_release_rqst_cong(struct rpc_task *task);
void xprt_disconnect_done(struct rpc_xprt *xprt);
void xprt_force_disconnect(struct rpc_xprt *xprt);
void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
+int xs_swapper(struct rpc_xprt *xprt, int enable);
/*
* Reserved bit positions in xprt->state
diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
index 9fe8857..03d03e3 100644
--- a/net/sunrpc/Kconfig
+++ b/net/sunrpc/Kconfig
@@ -21,6 +21,11 @@ config SUNRPC_XPRT_RDMA
If unsure, say N.
+config SUNRPC_SWAP
+ bool
+ depends on SUNRPC
+ select NETVM
+
config RPCSEC_GSS_KRB5
tristate "Secure RPC: Kerberos V mechanism"
depends on SUNRPC && CRYPTO
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 6797246..c01d35f 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -691,6 +691,8 @@ void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
atomic_inc(&clnt->cl_count);
if (clnt->cl_softrtry)
task->tk_flags |= RPC_TASK_SOFT;
+ if (task->tk_client->cl_xprt->swapper)
+ task->tk_flags |= RPC_TASK_SWAPPER;
/* Add to the client's list of all tasks */
spin_lock(&clnt->cl_lock);
list_add_tail(&task->tk_task, &clnt->cl_tasks);
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 994cfea..83a4c43 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -812,7 +812,10 @@ static void rpc_async_schedule(struct work_struct *work)
void *rpc_malloc(struct rpc_task *task, size_t size)
{
struct rpc_buffer *buf;
- gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT;
+ gfp_t gfp = GFP_NOWAIT;
+
+ if (RPC_IS_SWAPPER(task))
+ gfp |= __GFP_MEMALLOC;
size += sizeof(struct rpc_buffer);
if (size <= RPC_BUFFER_MAXSIZE)
@@ -886,7 +889,7 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta
static struct rpc_task *
rpc_alloc_task(void)
{
- return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
+ return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO);
}
/*
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 890b03f..b84df34 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1930,6 +1930,45 @@ out:
xprt_wake_pending_tasks(xprt, status);
}
+#ifdef CONFIG_SUNRPC_SWAP
+static void xs_set_memalloc(struct rpc_xprt *xprt)
+{
+ struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+ xprt);
+
+ if (xprt->swapper)
+ sk_set_memalloc(transport->inet);
+}
+
+/**
+ * xs_swapper - Tag this transport as being used for swap.
+ * @xprt: transport to tag
+ * @enable: enable/disable
+ *
+ */
+int xs_swapper(struct rpc_xprt *xprt, int enable)
+{
+ struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+ xprt);
+ int err = 0;
+
+ if (enable) {
+ xprt->swapper++;
+ xs_set_memalloc(xprt);
+ } else if (xprt->swapper) {
+ xprt->swapper--;
+ sk_clear_memalloc(transport->inet);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xs_swapper);
+#else
+static void xs_set_memalloc(struct rpc_xprt *xprt)
+{
+}
+#endif
+
static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
{
struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
@@ -1954,6 +1993,8 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
transport->sock = sock;
transport->inet = sk;
+ xs_set_memalloc(xprt);
+
write_unlock_bh(&sk->sk_callback_lock);
}
xs_udp_do_set_buffer_size(xprt);
@@ -1965,11 +2006,15 @@ static void xs_udp_setup_socket(struct work_struct *work)
container_of(work, struct sock_xprt, connect_worker.work);
struct rpc_xprt *xprt = &transport->xprt;
struct socket *sock = transport->sock;
+ unsigned long pflags = current->flags;
int status = -EIO;
if (xprt->shutdown)
goto out;
+ if (xprt->swapper)
+ current->flags |= PF_MEMALLOC;
+
/* Start by resetting any existing state */
xs_reset_transport(transport);
sock = xs_create_sock(xprt, transport,
@@ -1988,6 +2033,7 @@ static void xs_udp_setup_socket(struct work_struct *work)
out:
xprt_clear_connecting(xprt);
xprt_wake_pending_tasks(xprt, status);
+ tsk_restore_flags(current, pflags, PF_MEMALLOC);
}
/*
@@ -2078,6 +2124,8 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
if (!xprt_bound(xprt))
goto out;
+ xs_set_memalloc(xprt);
+
/* Tell the socket layer to start connecting... */
xprt->stat.connect_count++;
xprt->stat.connect_start = jiffies;
@@ -2108,11 +2156,15 @@ static void xs_tcp_setup_socket(struct work_struct *work)
container_of(work, struct sock_xprt, connect_worker.work);
struct socket *sock = transport->sock;
struct rpc_xprt *xprt = &transport->xprt;
+ unsigned long pflags = current->flags;
int status = -EIO;
if (xprt->shutdown)
goto out;
+ if (xprt->swapper)
+ current->flags |= PF_MEMALLOC;
+
if (!sock) {
clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
sock = xs_create_sock(xprt, transport,
@@ -2174,6 +2226,7 @@ out_eagain:
out:
xprt_clear_connecting(xprt);
xprt_wake_pending_tasks(xprt, status);
+ tsk_restore_flags(current, pflags, PF_MEMALLOC);
}
/**
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 10/11] nfs: Prevent page allocator recursions with swap over NFS.
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (8 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 09/11] nfs: enable swap on NFS Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-16 12:17 ` [PATCH 11/11] Avoid dereferencing bd_disk during swap_entry_free for network storage Mel Gorman
2012-04-21 18:13 ` [PATCH 00/11] Swap-over-NFS without deadlocking V3 Eric B Munson
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate
IO, just not of any filesystem data.
The problem is that previously NOFS was correct because that avoids
recursion into the NFS code. With swap-over-NFS, it is no longer
correct as swap IO can lead to this recursion.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
fs/nfs/pagelist.c | 2 +-
fs/nfs/write.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 77aa83e..8e80d71 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -29,7 +29,7 @@ static struct kmem_cache *nfs_page_cachep;
static inline struct nfs_page *
nfs_page_alloc(void)
{
- struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
+ struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO);
if (p)
INIT_LIST_HEAD(&p->wb_list);
return p;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index eea4ec0..c679527 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -52,7 +52,7 @@ static mempool_t *nfs_commit_mempool;
struct nfs_write_data *nfs_commitdata_alloc(void)
{
- struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
+ struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
if (p) {
memset(p, 0, sizeof(*p));
@@ -72,7 +72,7 @@ EXPORT_SYMBOL_GPL(nfs_commit_free);
struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
{
- struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
+ struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
if (p) {
memset(p, 0, sizeof(*p));
@@ -81,7 +81,8 @@ struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
if (pagecount <= ARRAY_SIZE(p->page_array))
p->pagevec = p->page_array;
else {
- p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
+ p->pagevec = kcalloc(pagecount, sizeof(struct page *),
+ GFP_NOIO);
if (!p->pagevec) {
mempool_free(p, nfs_wdata_mempool);
p = NULL;
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* [PATCH 11/11] Avoid dereferencing bd_disk during swap_entry_free for network storage
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (9 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 10/11] nfs: Prevent page allocator recursions with swap over NFS Mel Gorman
@ 2012-04-16 12:17 ` Mel Gorman
2012-04-21 18:13 ` [PATCH 00/11] Swap-over-NFS without deadlocking V3 Eric B Munson
11 siblings, 0 replies; 22+ messages in thread
From: Mel Gorman @ 2012-04-16 12:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Linux-MM, Linux-Netdev, Linux-NFS, LKML, David Miller,
Trond Myklebust, Neil Brown, Christoph Hellwig, Peter Zijlstra,
Mike Christie, Eric B Munson, Mel Gorman
Commit [b3a27d: swap: Add swap slot free callback to
block_device_operations] dereferences p->bdev->bd_disk but this is a
NULL dereference if using swap-over-NFS. This patch checks SWP_BLKDEV
on the swap_info_struct before dereferencing.
With reference to this callback, Christoph Hellwig stated "Please
just remove the callback entirely. It has no user outside the staging
tree and was added clearly against the rules for that staging tree".
This would also be my preference but there was not an obvious way of
keeping zram in staging/ happy.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/swapfile.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 80b3415..d85d842 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -547,7 +547,6 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
/* free if no reference */
if (!usage) {
- struct gendisk *disk = p->bdev->bd_disk;
if (offset < p->lowest_bit)
p->lowest_bit = offset;
if (offset > p->highest_bit)
@@ -557,9 +556,11 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
swap_list.next = p->type;
nr_swap_pages++;
p->inuse_pages--;
- if ((p->flags & SWP_BLKDEV) &&
- disk->fops->swap_slot_free_notify)
- disk->fops->swap_slot_free_notify(p->bdev, offset);
+ if (p->flags & SWP_BLKDEV) {
+ struct gendisk *disk = p->bdev->bd_disk;
+ if (disk->fops->swap_slot_free_notify)
+ disk->fops->swap_slot_free_notify(p->bdev, offset);
+ }
}
return usage;
--
1.7.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 22+ messages in thread* Re: [PATCH 00/11] Swap-over-NFS without deadlocking V3
2012-04-16 12:17 [PATCH 00/11] Swap-over-NFS without deadlocking V3 Mel Gorman
` (10 preceding siblings ...)
2012-04-16 12:17 ` [PATCH 11/11] Avoid dereferencing bd_disk during swap_entry_free for network storage Mel Gorman
@ 2012-04-21 18:13 ` Eric B Munson
11 siblings, 0 replies; 22+ messages in thread
From: Eric B Munson @ 2012-04-21 18:13 UTC (permalink / raw)
To: Mel Gorman
Cc: Andrew Morton, Linux-MM, Linux-Netdev, Linux-NFS, LKML,
David Miller, Trond Myklebust, Neil Brown, Christoph Hellwig,
Peter Zijlstra, Mike Christie
[-- Attachment #1: Type: text/plain, Size: 3547 bytes --]
On Mon, 16 Apr 2012, Mel Gorman wrote:
> Changelog since V2
> o Nothing significant, just rebases. A radix tree lookup is replaced with
> a linear search would be the biggest rebase artifact
>
> This patch series is based on top of "Swap-over-NBD without deadlocking v9"
> as it depends on the same reservation of PF_MEMALLOC reserves logic.
>
> When a user or administrator requires swap for their application, they
> create a swap partition and file, format it with mkswap and activate it with
> swapon. In diskless systems this is not an option so if swap if required
> then swapping over the network is considered. The two likely scenarios
> are when blade servers are used as part of a cluster where the form factor
> or maintenance costs do not allow the use of disks and thin clients.
>
> The Linux Terminal Server Project recommends the use of the Network
> Block Device (NBD) for swap but this is not always an option. There is
> no guarantee that the network attached storage (NAS) device is running
> Linux or supports NBD. However, it is likely that it supports NFS so there
> are users that want support for swapping over NFS despite any performance
> concern. Some distributions currently carry patches that support swapping
> over NFS but it would be preferable to support it in the mainline kernel.
>
> Patch 1 avoids a stream-specific deadlock that potentially affects TCP.
>
> Patch 2 is a small modification to SELinux to avoid using PFMEMALLOC
> reserves.
>
> Patch 3 adds three helpers for filesystems to handle swap cache pages.
> For example, page_file_mapping() returns page->mapping for
> file-backed pages and the address_space of the underlying
> swap file for swap cache pages.
>
> Patch 4 adds two address_space_operations to allow a filesystem
> to pin all metadata relevant to a swapfile in memory. Upon
> successful activation, the swapfile is marked SWP_FILE and
> the address space operation ->direct_IO is used for writing
> and ->readpage for reading in swap pages.
>
> Patch 5 notes that patch 3 is bolting
> filesystem-specific-swapfile-support onto the side and that
> the default handlers have different information to what
> is available to the filesystem. This patch refactors the
> code so that there are generic handlers for each of the new
> address_space operations.
>
> Patch 6 adds an API to allow a vector of kernel addresses to be
> translated to struct pages and pinned for IO.
>
> Patch 7 updates NFS to use the helpers from patch 3 where necessary.
>
> Patch 8 avoids setting PF_private on PG_swapcache pages within NFS.
>
> Patch 9 implements the new swapfile-related address_space operations
> for NFS and teaches the direct IO handler how to manage
> kernel addresses.
>
> Patch 10 prevents page allocator recursions in NFS by using GFP_NOIO
> where appropriate.
>
> Patch 11 fixes a NULL pointer dereference that occurs when using
> swap-over-NFS.
>
> With the patches applied, it is possible to mount a swapfile that is on an
> NFS filesystem. Swap performance is not great with a swap stress test taking
> roughly twice as long to complete than if the swap device was backed by NBD.
>
FWIW, I'd like to see these go in, I use them for giving ARM boards with NFS
root file systems swap space.
I have tested these with an artificial swap benchmark and with a large project
compile on a beagle board. They work great for me.
Tested-by: Eric B Munson <emunson@mgebm.net>
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]
^ permalink raw reply [flat|nested] 22+ messages in thread