From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: [PATCH 07/13] Use atomic-long operations instead of looping around cmpxchg(). Date: Tue, 23 Aug 2011 18:56:20 +1000 Message-ID: <1314089786-20535-8-git-send-email-david@fromorbit.com> References: <1314089786-20535-1-git-send-email-david@fromorbit.com> Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, khlebnikov@openvz.org To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1314089786-20535-1-git-send-email-david@fromorbit.com> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org From: Konstantin Khlebnikov Signed-off-by: Konstantin Khlebnikov Reviewed-by: Dave Chinner --- include/linux/fs.h | 2 +- include/linux/shrinker.h | 2 +- mm/vmscan.c | 17 +++++++---------- 3 files changed, 9 insertions(+), 12 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 958c025..2651059 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -394,8 +394,8 @@ struct inodes_stat_t { #include #include #include -#include #include +#include #include diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index ab6c572..02b5b6b 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -43,7 +43,7 @@ struct shrinker { /* These are for internal use */ struct list_head list; - long nr; /* objs pending delete */ + atomic_long_t nr_pending; /* objs pending delete */ }; #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */ diff --git a/mm/vmscan.c b/mm/vmscan.c index e32ce2d..534ed34 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -184,7 +184,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone, */ void register_shrinker(struct shrinker *shrinker) { - shrinker->nr = 0; + atomic_long_set(&shrinker->nr_pending, 0); down_write(&shrinker_rwsem); list_add_tail(&shrinker->list, &shrinker_list); up_write(&shrinker_rwsem); @@ -252,9 +252,7 @@ unsigned long shrink_slab(struct shrink_control *sc, * 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_pending, 0); total_scan = nr; max_pass = shrinker->count_objects(shrinker, sc); @@ -318,12 +316,11 @@ unsigned long shrink_slab(struct shrink_control *sc, * 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_pending); + else + new_nr = atomic_long_read(&shrinker->nr_pending); trace_mm_shrink_slab_end(shrinker, freed, nr, new_nr); } -- 1.7.5.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org