Commit f6bb2a2c authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

xarray: add the xa_lock to the radix_tree_root 

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.

Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5a95541

fs/f2fs/gc.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1015,7 +1015,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, 
	unsigned int init_segno = segno;

	unsigned int init_segno = segno;

	struct gc_inode_list gc_list = {

	struct gc_inode_list gc_list = {

		.ilist = LIST_HEAD_INIT(gc_list.ilist),

		.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,

	trace_f2fs_gc_begin(sbi->sb, sync, background,

include/linux/idr.h

+10 −9
Original line number Original line Diff line number Diff line
@@ -32,27 +32,28 @@ struct idr { 
#define IDR_RT_MARKER	(ROOT_IS_IDR | (__force gfp_t)			\

#define IDR_RT_MARKER	(ROOT_IS_IDR | (__force gfp_t)			\

					(1 << (ROOT_TAG_SHIFT + IDR_FREE)))

					(1 << (ROOT_TAG_SHIFT + IDR_FREE)))





#define IDR_INIT_BASE(base) {						\

#define IDR_INIT_BASE(name, base) {					\

	.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER),			\

	.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER),			\

	.idr_base = (base),						\

	.idr_base = (base),						\

	.idr_next = 0,							\

	.idr_next = 0,							\

}

}





/**

/**

 * IDR_INIT() - Initialise an IDR.

 * IDR_INIT() - Initialise an IDR.

 * @name: Name of IDR.

 *

 *

 * A freshly-initialised IDR contains no IDs.

 * 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

 * DEFINE_IDR() - Define a statically-allocated IDR.

 * @name: Name of IDR

 * @name: Name of IDR.

 *

 *

 * An IDR defined using this macro is ready for use with no additional

 * An IDR defined using this macro is ready for use with no additional

 * initialisation required.  It contains no IDs.

 * 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

 * idr_get_cursor - Return the current position of the cyclic allocator
@@ -219,10 +220,10 @@ struct ida { 
	struct radix_tree_root	ida_rt;

	struct radix_tree_root	ida_rt;

};

};





#define IDA_INIT	{						\

#define IDA_INIT(name)	{						\

	.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT),		\

	.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_pre_get(struct ida *ida, gfp_t gfp_mask);

int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);

int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);

include/linux/radix-tree.h

+5 −2
Original line number Original line Diff line number Diff line
@@ -110,20 +110,23 @@ struct radix_tree_node { 
#define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT)

#define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT)





struct radix_tree_root {

struct radix_tree_root {

	spinlock_t		xa_lock;

	gfp_t			gfp_mask;

	gfp_t			gfp_mask;

	struct radix_tree_node	__rcu *rnode;

	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),						\

	.gfp_mask = (mask),						\

	.rnode = NULL,							\

	.rnode = NULL,							\

}

}





#define RADIX_TREE(name, mask) \

#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)					\

#define INIT_RADIX_TREE(root, mask)					\

do {									\

do {									\

	spin_lock_init(&(root)->xa_lock);				\

	(root)->gfp_mask = (mask);					\

	(root)->gfp_mask = (mask);					\

	(root)->rnode = NULL;						\

	(root)->rnode = NULL;						\

} while (0)

} while (0)

include/linux/xarray.h

0 → 100644
+24 −0
Original line number Original line Diff line number Diff line 
/* 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 */

kernel/pid.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -70,7 +70,7 @@ int pid_max_max = PID_MAX_LIMIT; 
 */

 */

struct pid_namespace init_pid_ns = {

struct pid_namespace init_pid_ns = {

	.kref = KREF_INIT(2),

	.kref = KREF_INIT(2),

	.idr = IDR_INIT,

	.idr = IDR_INIT(init_pid_ns.idr),

	.pid_allocated = PIDNS_ADDING,

	.pid_allocated = PIDNS_ADDING,

	.level = 0,

	.level = 0,

	.child_reaper = &init_task,

	.child_reaper = &init_task,

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