Re: [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> +	/*
> +	 * If an allocation failed after direct reclaim, it could be because
> +	 * pages are pinned on the per-cpu lists. Drain them and try again
> +	 */
> +	if (!page && !drained) {
> +		drain_all_pages();
> +		drained = true;
> +		goto retry;
> +	}

nit: when slub, get_page_from_freelist() failure is frequently happen
than slab because slub try to allocate high order page at first.
So, I guess we have to avoid drain_all_pages() if __GFP_NORETRY is passed.




From 9209ceb1d48446b031576ba9360036ddabc1a0e5 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Fri, 10 Sep 2010 03:29:05 +0900
Subject: [PATCH] mm: don't call drain_all_pages() when __GFP_NORETRY

SLUB try to allocate high order pages at first. therefore page allocator
eventually call drain_all_pages() frequently. We don't hope IPI storm.
Thus, we don't call drain_all_pages() when caller passed __GFP_NORETRY.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
 mm/page_alloc.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8587c10..b9eafb1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1878,7 +1878,7 @@ retry:
 	 * If an allocation failed after direct reclaim, it could be because
 	 * pages are pinned on the per-cpu lists. Drain them and try again
 	 */
-	if (!page && !drained) {
+	if (!page && !drained && !(gfp_mask & __GFP_NORETRY)) {
 		drain_all_pages();
 		drained = true;
 		goto retry;
-- 
1.6.5.2



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