From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Neil Brown <neilb@suse.de>, Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Li, Shaohua" <shaohua.li@intel.com>
Subject: [PATCH] vmscan: comment too_many_isolated()
Date: Fri, 22 Oct 2010 12:55:54 +0800 [thread overview]
Message-ID: <20101022045554.GA17073@localhost> (raw)
In-Reply-To: <20101022045509.GA16804@localhost>
Comment "Why it's doing so" rather than "What it does"
as proposed by Andrew Morton.
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/vmscan.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- linux-next.orig/mm/vmscan.c 2010-10-19 09:29:44.000000000 +0800
+++ linux-next/mm/vmscan.c 2010-10-19 10:21:41.000000000 +0800
@@ -1142,7 +1142,11 @@ 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)
WARNING: multiple messages have this Message-ID (diff)
From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Neil Brown <neilb@suse.de>, Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Li, Shaohua" <shaohua.li@intel.com>
Subject: [PATCH] vmscan: comment too_many_isolated()
Date: Fri, 22 Oct 2010 12:55:54 +0800 [thread overview]
Message-ID: <20101022045554.GA17073@localhost> (raw)
In-Reply-To: <20101022045509.GA16804@localhost>
Comment "Why it's doing so" rather than "What it does"
as proposed by Andrew Morton.
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/vmscan.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- linux-next.orig/mm/vmscan.c 2010-10-19 09:29:44.000000000 +0800
+++ linux-next/mm/vmscan.c 2010-10-19 10:21:41.000000000 +0800
@@ -1142,7 +1142,11 @@ 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)
--
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next prev parent reply other threads:[~2010-10-22 4:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-22 4:55 [PATCH] mm: Avoid possible deadlock caused by too_many_isolated() Wu Fengguang
2010-10-22 4:55 ` Wu Fengguang
2010-10-22 4:55 ` Wu Fengguang [this message]
2010-10-22 4:55 ` [PATCH] vmscan: comment too_many_isolated() Wu Fengguang
2010-10-22 12:00 ` Rik van Riel
2010-10-22 12:00 ` Rik van Riel
2010-10-22 12:00 ` [PATCH] mm: Avoid possible deadlock caused by too_many_isolated() Rik van Riel
2010-10-22 12:00 ` Rik van Riel
2010-10-24 22:55 ` Minchan Kim
2010-10-24 22:55 ` Minchan Kim
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