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Commit 83aeeada authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Linus Torvalds
Browse files

vmscan: use atomic-long for shrinker batching 



Use atomic-long operations instead of looping around cmpxchg().

[akpm@linux-foundation.org: massage atomic.h inclusions]
Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 635697c6

include/linux/fs.h

+1 −1
Original line number Diff line number Diff line
@@ -393,8 +393,8 @@ struct inodes_stat_t { 
#include <linux/semaphore.h>

#include <linux/fiemap.h>

#include <linux/rculist_bl.h>

#include <linux/shrinker.h>

#include <linux/atomic.h>

#include <linux/shrinker.h>



#include <asm/byteorder.h>

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/mmzone.h>

#include <linux/rbtree.h>

#include <linux/prio_tree.h>

#include <linux/atomic.h>

#include <linux/debug_locks.h>

#include <linux/mm_types.h>

#include <linux/range.h>

include/linux/shrinker.h

+1 −1
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ struct shrinker { 


	/* These are for internal use */

	struct list_head list;

	long nr;	/* objs pending delete */

	atomic_long_t nr_in_batch; /* objs pending delete */

};

#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */

extern void register_shrinker(struct shrinker *);

mm/vmscan.c

+7 −10
Original line number Diff line number Diff line
@@ -183,7 +183,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone, 
 */

void register_shrinker(struct shrinker *shrinker)

{

	shrinker->nr = 0;

	atomic_long_set(&shrinker->nr_in_batch, 0);

	down_write(&shrinker_rwsem);

	list_add_tail(&shrinker->list, &shrinker_list);

	up_write(&shrinker_rwsem);
@@ -264,9 +264,7 @@ unsigned long shrink_slab(struct shrink_control *shrink, 
		 * and zero it so that other concurrent shrinker invocations

		 * don't also do this scanning work.

		 */

		do {

			nr = shrinker->nr;

		} while (cmpxchg(&shrinker->nr, nr, 0) != nr);

		nr = atomic_long_xchg(&shrinker->nr_in_batch, 0);



		total_scan = nr;

		delta = (4 * nr_pages_scanned) / shrinker->seeks;
@@ -328,12 +326,11 @@ unsigned long shrink_slab(struct shrink_control *shrink, 
		 * manner that handles concurrent updates. If we exhausted the

		 * scan, there is no need to do an update.

		 */

		do {

			nr = shrinker->nr;

			new_nr = total_scan + nr;

			if (total_scan <= 0)

				break;

		} while (cmpxchg(&shrinker->nr, nr, new_nr) != nr);

		if (total_scan > 0)

			new_nr = atomic_long_add_return(total_scan,

					&shrinker->nr_in_batch);

		else

			new_nr = atomic_long_read(&shrinker->nr_in_batch);



		trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr);

	}