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From: Matthew Wilcox <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org,
	Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
	linux-nilfs@vger.kernel.org
Subject: [PATCH v9 07/61] xarray: Add the xa_lock to the radix_tree_root
Date: Tue, 13 Mar 2018 06:25:45 -0700
Message-ID: <20180313132639.17387-8-willy@infradead.org> (raw)
In-Reply-To: <20180313132639.17387-1-willy@infradead.org>

From: Matthew Wilcox <mawilcox@microsoft.com>

This results in no change in structure size on 64-bit machines as it
fits in the padding between the gfp_t and the void *.  32-bit machines
will grow the structure from 8 to 12 bytes.  Almost all radix trees
are protected with (at least) a spinlock, so as they are converted from
radix trees to xarrays, the data structures will shrink again.

Initialising the spinlock requires a name for the benefit of lockdep,
so RADIX_TREE_INIT() now needs to know the name of the radix tree it's
initialising, and so do IDR_INIT() and IDA_INIT().

Also add the xa_lock() and xa_unlock() family of wrappers to make it
easier to use the lock.  If we could rely on -fplan9-extensions in
the compiler, we could avoid all of this syntactic sugar, but that
wasn't added until gcc 4.6.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
---
 fs/f2fs/gc.c                   |  2 +-
 include/linux/idr.h            | 19 ++++++++++---------
 include/linux/radix-tree.h     |  7 +++++--
 include/linux/xarray.h         | 24 ++++++++++++++++++++++++
 kernel/pid.c                   |  2 +-
 tools/include/linux/spinlock.h |  1 +
 6 files changed, 42 insertions(+), 13 deletions(-)
 create mode 100644 include/linux/xarray.h

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index aa720cc44509..7aa15134180e 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1006,7 +1006,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 	unsigned int init_segno = segno;
 	struct gc_inode_list gc_list = {
 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
-		.iroot = RADIX_TREE_INIT(GFP_NOFS),
+		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
 	};
 
 	trace_f2fs_gc_begin(sbi->sb, sync, background,
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 913c335054f0..e856f4e0ab35 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -32,27 +32,28 @@ struct idr {
 #define IDR_RT_MARKER	(ROOT_IS_IDR | (__force gfp_t)			\
 					(1 << (ROOT_TAG_SHIFT + IDR_FREE)))
 
-#define IDR_INIT_BASE(base) {						\
-	.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER),			\
+#define IDR_INIT_BASE(name, base) {					\
+	.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER),			\
 	.idr_base = (base),						\
 	.idr_next = 0,							\
 }
 
 /**
  * IDR_INIT() - Initialise an IDR.
+ * @name: Name of IDR.
  *
  * A freshly-initialised IDR contains no IDs.
  */
-#define IDR_INIT	IDR_INIT_BASE(0)
+#define IDR_INIT(name)	IDR_INIT_BASE(name, 0)
 
 /**
- * DEFINE_IDR() - Define a statically-allocated IDR
- * @name: Name of IDR
+ * DEFINE_IDR() - Define a statically-allocated IDR.
+ * @name: Name of IDR.
  *
  * An IDR defined using this macro is ready for use with no additional
  * initialisation required.  It contains no IDs.
  */
-#define DEFINE_IDR(name)	struct idr name = IDR_INIT
+#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)
 
 /**
  * idr_get_cursor - Return the current position of the cyclic allocator
@@ -219,10 +220,10 @@ struct ida {
 	struct radix_tree_root	ida_rt;
 };
 
-#define IDA_INIT	{						\
-	.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT),		\
+#define IDA_INIT(name)	{						\
+	.ida_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER | GFP_NOWAIT),	\
 }
-#define DEFINE_IDA(name)	struct ida name = IDA_INIT
+#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
 
 int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
 int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 6c4e2e716dac..34149e8b5f73 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -110,20 +110,23 @@ struct radix_tree_node {
 #define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT)
 
 struct radix_tree_root {
+	spinlock_t		xa_lock;
 	gfp_t			gfp_mask;
 	struct radix_tree_node	__rcu *rnode;
 };
 
-#define RADIX_TREE_INIT(mask)	{					\
+#define RADIX_TREE_INIT(name, mask)	{				\
+	.xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock),			\
 	.gfp_mask = (mask),						\
 	.rnode = NULL,							\
 }
 
 #define RADIX_TREE(name, mask) \
-	struct radix_tree_root name = RADIX_TREE_INIT(mask)
+	struct radix_tree_root name = RADIX_TREE_INIT(name, mask)
 
 #define INIT_RADIX_TREE(root, mask)					\
 do {									\
+	spin_lock_init(&(root)->xa_lock);				\
 	(root)->gfp_mask = (mask);					\
 	(root)->rnode = NULL;						\
 } while (0)
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
new file mode 100644
index 000000000000..2dfc8006fe64
--- /dev/null
+++ b/include/linux/xarray.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _LINUX_XARRAY_H
+#define _LINUX_XARRAY_H
+/*
+ * eXtensible Arrays
+ * Copyright (c) 2017 Microsoft Corporation
+ * Author: Matthew Wilcox <mawilcox@microsoft.com>
+ */
+
+#include <linux/spinlock.h>
+
+#define xa_trylock(xa)		spin_trylock(&(xa)->xa_lock)
+#define xa_lock(xa)		spin_lock(&(xa)->xa_lock)
+#define xa_unlock(xa)		spin_unlock(&(xa)->xa_lock)
+#define xa_lock_bh(xa)		spin_lock_bh(&(xa)->xa_lock)
+#define xa_unlock_bh(xa)	spin_unlock_bh(&(xa)->xa_lock)
+#define xa_lock_irq(xa)		spin_lock_irq(&(xa)->xa_lock)
+#define xa_unlock_irq(xa)	spin_unlock_irq(&(xa)->xa_lock)
+#define xa_lock_irqsave(xa, flags) \
+				spin_lock_irqsave(&(xa)->xa_lock, flags)
+#define xa_unlock_irqrestore(xa, flags) \
+				spin_unlock_irqrestore(&(xa)->xa_lock, flags)
+
+#endif /* _LINUX_XARRAY_H */
diff --git a/kernel/pid.c b/kernel/pid.c
index ed6c343fe50d..157fe4b19971 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -70,7 +70,7 @@ int pid_max_max = PID_MAX_LIMIT;
  */
 struct pid_namespace init_pid_ns = {
 	.kref = KREF_INIT(2),
-	.idr = IDR_INIT,
+	.idr = IDR_INIT(init_pid_ns.idr),
 	.pid_allocated = PIDNS_ADDING,
 	.level = 0,
 	.child_reaper = &init_task,
diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h
index 4ed569fcb139..b21b586b9854 100644
--- a/tools/include/linux/spinlock.h
+++ b/tools/include/linux/spinlock.h
@@ -7,6 +7,7 @@
 
 #define spinlock_t		pthread_mutex_t
 #define DEFINE_SPINLOCK(x)	pthread_mutex_t x = PTHREAD_MUTEX_INITIALIZER;
+#define __SPIN_LOCK_UNLOCKED(x)	(pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER
 
 #define spin_lock_irqsave(x, f)		(void)f, pthread_mutex_lock(x)
 #define spin_unlock_irqrestore(x, f)	(void)f, pthread_mutex_unlock(x)
-- 
2.16.1

  parent reply index

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-13 13:25 [PATCH v9 00/61] XArray v9 Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 01/61] mac80211_hwsim: Use DEFINE_IDA Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 02/61] radix tree: Use GFP_ZONEMASK bits of gfp_t for flags Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 03/61] arm64: Turn flush_dcache_mmap_lock into a no-op Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 04/61] unicore32: " Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 05/61] Export __set_page_dirty Matthew Wilcox
2018-03-27  0:28   ` Darrick J. Wong
2018-03-13 13:25 ` [PATCH v9 06/61] fscache: Use appropriate radix tree accessors Matthew Wilcox
2018-03-13 13:25 ` Matthew Wilcox [this message]
2018-04-12 20:59   ` [PATCH v9 07/61] xarray: Add the xa_lock to the radix_tree_root Ross Zwisler
2018-04-12 21:10     ` Matthew Wilcox
2018-04-12 21:16       ` Ross Zwisler
2018-04-12 21:22         ` Matthew Wilcox
2018-04-12 21:27           ` Ross Zwisler
2018-03-13 13:25 ` [PATCH v9 08/61] page cache: Use xa_lock Matthew Wilcox
2018-03-16 18:06   ` Josef Bacik
2018-03-13 13:25 ` [PATCH v9 09/61] xarray: Replace exceptional entries Matthew Wilcox
2018-03-16 18:53   ` Josef Bacik
2018-03-16 19:06     ` Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 10/61] xarray: Change definition of sibling entries Matthew Wilcox
2018-03-16 19:00   ` Josef Bacik
2018-03-13 13:25 ` [PATCH v9 11/61] xarray: Add definition of struct xarray Matthew Wilcox
2018-03-16 19:05   ` Josef Bacik
2018-03-13 13:25 ` [PATCH v9 12/61] xarray: Define struct xa_node Matthew Wilcox
2018-03-16 19:11   ` Josef Bacik
2018-03-13 13:25 ` [PATCH v9 13/61] xarray: Add documentation Matthew Wilcox
2018-03-16 19:12   ` Josef Bacik
2018-03-13 13:25 ` [PATCH v9 14/61] xarray: Add xa_load Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 15/61] xarray: Add xa_get_tag, xa_set_tag and xa_clear_tag Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 16/61] xarray: Add xa_store Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 17/61] xarray: Add xa_cmpxchg and xa_insert Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 18/61] xarray: Add xa_for_each Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 19/61] xarray: Add xa_extract Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 20/61] xarray: Add xa_destroy Matthew Wilcox
2018-03-13 13:25 ` [PATCH v9 21/61] xarray: Add xas_next and xas_prev Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 22/61] xarray: Add xas_create_range Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 23/61] xarray: Add MAINTAINERS entry Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 24/61] page cache: Rearrange address_space Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 25/61] page cache: Convert hole search to XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 26/61] page cache: Add and replace pages using the XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 27/61] page cache: Convert page deletion to XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 28/61] page cache: Convert page cache lookups " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 29/61] page cache: Convert delete_batch " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 30/61] page cache: Remove stray radix comment Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 31/61] page cache: Convert filemap_range_has_page to XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 32/61] mm: Convert page-writeback " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 33/61] mm: Convert workingset " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 34/61] mm: Convert truncate " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 35/61] mm: Convert add_to_swap_cache " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 36/61] mm: Convert delete_from_swap_cache " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 37/61] mm: Convert __do_page_cache_readahead " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 38/61] mm: Convert page migration " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 39/61] mm: Convert huge_memory " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 40/61] mm: Convert collapse_shmem " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 41/61] mm: Convert khugepaged_scan_shmem " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 42/61] pagevec: Use xa_tag_t Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 43/61] shmem: Convert replace to XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 44/61] shmem: Convert shmem_confirm_swap " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 45/61] shmem: Convert find_swap_entry " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 46/61] shmem: Convert shmem_add_to_page_cache " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 47/61] shmem: Convert shmem_alloc_hugepage " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 48/61] shmem: Convert shmem_free_swap " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 49/61] shmem: Convert shmem_partial_swap_usage " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 50/61] memfd: Convert shmem_tag_pins " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 51/61] memfd: Convert shmem_wait_for_pins " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 52/61] shmem: Comment fixups Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 53/61] btrfs: Convert page cache to XArray Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 54/61] fs: Convert buffer " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 55/61] fs: Convert writeback " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 56/61] nilfs2: Convert " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 57/61] f2fs: " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 58/61] lustre: " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 59/61] dax: " Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 60/61] page cache: Finish XArray conversion Matthew Wilcox
2018-03-13 13:26 ` [PATCH v9 61/61] radix tree: Remove unused functions Matthew Wilcox
2018-03-26 22:36 ` [PATCH v9 00/61] XArray v9 Andrew Morton
2018-03-26 23:26   ` Matthew Wilcox

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