From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx181.postini.com [74.125.245.181]) by kanga.kvack.org (Postfix) with SMTP id E586F6B004D for ; Sat, 31 Dec 2011 01:17:49 -0500 (EST) From: Huang Shijie Subject: [PATCH] mm/compaction : check the watermark when cc->order is -1 Date: Sat, 31 Dec 2011 14:18:43 +0800 Message-ID: <1325312323-13565-1-git-send-email-b32955@freescale.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: mgorman@suse.de, linux-mm@kvack.org, Huang Shijie We get cc->order is -1 when user echos to /proc/sys/vm/compact_memory. In this case, we should check that if we have enough pages for the compaction in the zone. If we do not check this, in our MX6Q board(arm), i ever observed COMPACT_CLUSTER_MAX pages were compaction failed in per migrate_pages(). That's mean we can not alloc any pages by the free scanner in the zone. This patch checks the watermark to avoid this problem. Signed-off-by: Huang Shijie --- mm/compaction.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 899d956..0f12cc9 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -442,8 +442,13 @@ static int compact_finished(struct zone *zone, * order == -1 is expected when compacting via * /proc/sys/vm/compact_memory */ - if (cc->order == -1) + if (cc->order == -1) { + /* Check if we have enough pages now. */ + watermark = low_wmark_pages(zone) + COMPACT_CLUSTER_MAX * 2; + if (!zone_watermark_ok(zone, 0, watermark, 0, 0)) + return COMPACT_SKIPPED; return COMPACT_CONTINUE; + } /* Compaction run is not finished if the watermark is not met */ watermark = low_wmark_pages(zone); @@ -482,8 +487,13 @@ unsigned long compaction_suitable(struct zone *zone, int order) * order == -1 is expected when compacting via * /proc/sys/vm/compact_memory */ - if (order == -1) + if (order == -1) { + /* Check if we have enough pages now. */ + watermark = low_wmark_pages(zone) + COMPACT_CLUSTER_MAX * 2; + if (!zone_watermark_ok(zone, 0, watermark, 0, 0)) + return COMPACT_SKIPPED; return COMPACT_CONTINUE; + } /* * Watermarks for order-0 must be met for compaction. Note the 2UL. -- 1.7.3.2 -- 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