Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
authored by
Konstantin Khlebnikov
and committed by
Linus Torvalds
83aeeada
635697c6
+10
-12
+1
-1
include/linux/fs.h
+1
-1
include/linux/fs.h
+1
include/linux/mm.h
+1
include/linux/mm.h
+1
-1
include/linux/shrinker.h
+1
-1
include/linux/shrinker.h
···
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/* These are for internal use */
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struct list_head list;
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-
long nr; /* objs pending delete */
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+
atomic_long_t nr_in_batch; /* objs pending delete */
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};
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#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
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extern void register_shrinker(struct shrinker *);
+7
-10
mm/vmscan.c
+7
-10
mm/vmscan.c
···
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*/
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void register_shrinker(struct shrinker *shrinker)
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{
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shrinker->nr = 0;
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atomic_long_set(&shrinker->nr_in_batch, 0);
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down_write(&shrinker_rwsem);
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list_add_tail(&shrinker->list, &shrinker_list);
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up_write(&shrinker_rwsem);
···
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* and zero it so that other concurrent shrinker invocations
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* don't also do this scanning work.
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*/
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do {
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nr = shrinker->nr;
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-
} while (cmpxchg(&shrinker->nr, nr, 0) != nr);
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nr = atomic_long_xchg(&shrinker->nr_in_batch, 0);
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total_scan = nr;
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delta = (4 * nr_pages_scanned) / shrinker->seeks;
···
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* manner that handles concurrent updates. If we exhausted the
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* scan, there is no need to do an update.
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*/
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do {
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nr = shrinker->nr;
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new_nr = total_scan + nr;
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-
if (total_scan <= 0)
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break;
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} while (cmpxchg(&shrinker->nr, nr, new_nr) != nr);
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+
if (total_scan > 0)
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new_nr = atomic_long_add_return(total_scan,
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&shrinker->nr_in_batch);
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else
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new_nr = atomic_long_read(&shrinker->nr_in_batch);
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trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr);
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}