Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759026Ab1EMODd (ORCPT ); Fri, 13 May 2011 10:03:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53069 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399Ab1EMODa (ORCPT ); Fri, 13 May 2011 10:03:30 -0400 From: Mel Gorman To: Andrew Morton Cc: James Bottomley , Colin King , Raghavendra D Prabhu , Jan Kara , Chris Mason , Christoph Lameter , Pekka Enberg , Rik van Riel , Johannes Weiner , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 , Mel Gorman Subject: [PATCH 2/4] mm: slub: Do not wake kswapd for SLUBs speculative high-order allocations Date: Fri, 13 May 2011 15:03:22 +0100 Message-Id: <1305295404-12129-3-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: <1305295404-12129-1-git-send-email-mgorman@suse.de> References: <1305295404-12129-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1542 Lines: 37 To avoid locking and per-cpu overhead, SLUB optimisically uses high-order allocations and falls back to lower allocations if they fail. However, by simply trying to allocate, kswapd is woken up to start reclaiming at that order. On a desktop system, two users report that the system is getting locked up with kswapd using large amounts of CPU. Using SLAB instead of SLUB made this problem go away. This patch prevents kswapd being woken up for high-order allocations. Testing indicated that with this patch applied, the system was much harder to hang and even when it did, it eventually recovered. Signed-off-by: Mel Gorman --- mm/slub.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 9d2e5e4..98c358d 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1170,7 +1170,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) * Let the initial higher-order allocation fail under memory pressure * so we fall-back to the minimum order allocation. */ - alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; + alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) & ~__GFP_NOFAIL; page = alloc_slab_page(alloc_gfp, node, oo); if (unlikely(!page)) { -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/