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| author | Fengguang Wu <fengguang.wu@intel.com> | 2012-12-18 14:23:28 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-18 15:02:15 -0800 |
| commit | d37dd5dcb955dd8c2cdd4eaef1f15d1b7ecbc379 (patch) | |
| tree | 604209843c03b53a6c74f90cdb7d000914213066 /mm/vmscan.c | |
| parent | dc053733ea44babedb20266300b984d6add8b9e5 (diff) | |
| download | lwn-d37dd5dcb955dd8c2cdd4eaef1f15d1b7ecbc379.tar.gz lwn-d37dd5dcb955dd8c2cdd4eaef1f15d1b7ecbc379.zip | |
vmscan: comment too_many_isolated()
Comment "Why it's doing so" rather than "What it does" as proposed by
Andrew Morton.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 7f3096137b8a..e73d0206dddd 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1177,7 +1177,11 @@ int isolate_lru_page(struct page *page) } /* - * Are there way too many processes in the direct reclaim path already? + * A direct reclaimer may isolate SWAP_CLUSTER_MAX pages from the LRU list and + * then get resheduled. When there are massive number of tasks doing page + * allocation, such sleeping direct reclaimers may keep piling up on each CPU, + * the LRU list will go small and be scanned faster than necessary, leading to + * unnecessary swapping, thrashing and OOM. */ static int too_many_isolated(struct zone *zone, int file, struct scan_control *sc) |