The patch titled
Subject: vmscan: comment too_many_isolated()
has been added to the -mm tree. Its filename is
vmscan-comment-too_many_isolated.patch
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------------------------------------------------------
From: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Subject: 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@xxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff -puN mm/vmscan.c~vmscan-comment-too_many_isolated mm/vmscan.c
--- a/mm/vmscan.c~vmscan-comment-too_many_isolated
+++ a/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)
_
Patches currently in -mm which might be from fengguang.wu@xxxxxxxxx are
origin.patch
linux-next.patch
h8300-select-generic-atomic64_t-support.patch
vmscan-comment-too_many_isolated.patch
swap-add-a-simple-detector-for-inappropriate-swapin-readahead.patch
swap-add-a-simple-detector-for-inappropriate-swapin-readahead-fix.patch
hfsplus-rework-functionality-of-getting-setting-and-deleting-of-extended-attributes-fix.patch
fs-notify-add-procfs-fdinfo-helper-v7-fix-fix.patch
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