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| author | Konstantin Khlebnikov <khlebnikov@openvz.org> | 2011-12-08 14:33:54 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-09 07:50:27 -0800 |
| commit | 83aeeada7c69f35e5100b27ec354335597a7a488 (patch) | |
| tree | 44644e68f303368feba7c8ba3e0e0991d6238ada | |
| parent | 635697c663f38106063d5659f0cf2e45afcd4bb5 (diff) | |
| download | lwn-83aeeada7c69f35e5100b27ec354335597a7a488.tar.gz lwn-83aeeada7c69f35e5100b27ec354335597a7a488.zip | |
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: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/fs.h | 2 | ||||
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | include/linux/shrinker.h | 2 | ||||
| -rw-r--r-- | mm/vmscan.c | 17 |
4 files changed, 10 insertions, 12 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 019dc558df1a..e0bc4ffb8e7f 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -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> diff --git a/include/linux/mm.h b/include/linux/mm.h index 3dc3a8c2c485..4baadd18f4ad 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index a83833a1f7a2..07ceb97d53fa 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -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 *); diff --git a/mm/vmscan.c b/mm/vmscan.c index f5255442ae2b..f54a05b7a61d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -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); } |