From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935198Ab3DILSL (ORCPT ); Tue, 9 Apr 2013 07:18:11 -0400 Received: from cantor2.suse.de ([195.135.220.15]:50290 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763878Ab3DILSH (ORCPT ); Tue, 9 Apr 2013 07:18:07 -0400 From: Mel Gorman To: Andrew Morton Cc: Jiri Slaby , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , Michal Hocko , Linux-MM , LKML , Mel Gorman Subject: [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Date: Tue, 9 Apr 2013 12:07:00 +0100 Message-Id: <1365505625-9460-6-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1365505625-9460-1-git-send-email-mgorman@suse.de> References: <1365505625-9460-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Page reclaim at priority 0 will scan the entire LRU as priority 0 is considered to be a near OOM condition. Kswapd can reach priority 0 quite easily if it is encountering a large number of pages it cannot reclaim such as pages under writeback. When this happens, kswapd reclaims very aggressively even though there may be no real risk of allocation failure or OOM. This patch prevents kswapd reaching priority 0 and trying to reclaim the world. Direct reclaimers will still reach priority 0 in the event of an OOM situation. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Reviewed-by: Michal Hocko --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index a9e68b4..3d8b80a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2906,7 +2906,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, */ if (raise_priority || !this_reclaimed) sc.priority--; - } while (sc.priority >= 0 && + } while (sc.priority >= 1 && !pgdat_balanced(pgdat, order, *classzone_idx)); out: -- 1.8.1.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx157.postini.com [74.125.245.157]) by kanga.kvack.org (Postfix) with SMTP id A0A696B003B for ; Tue, 9 Apr 2013 07:18:07 -0400 (EDT) From: Mel Gorman Subject: [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Date: Tue, 9 Apr 2013 12:07:00 +0100 Message-Id: <1365505625-9460-6-git-send-email-mgorman@suse.de> In-Reply-To: <1365505625-9460-1-git-send-email-mgorman@suse.de> References: <1365505625-9460-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Jiri Slaby , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , Michal Hocko , Linux-MM , LKML , Mel Gorman Page reclaim at priority 0 will scan the entire LRU as priority 0 is considered to be a near OOM condition. Kswapd can reach priority 0 quite easily if it is encountering a large number of pages it cannot reclaim such as pages under writeback. When this happens, kswapd reclaims very aggressively even though there may be no real risk of allocation failure or OOM. This patch prevents kswapd reaching priority 0 and trying to reclaim the world. Direct reclaimers will still reach priority 0 in the event of an OOM situation. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Reviewed-by: Michal Hocko --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index a9e68b4..3d8b80a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2906,7 +2906,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order, */ if (raise_priority || !this_reclaimed) sc.priority--; - } while (sc.priority >= 0 && + } while (sc.priority >= 1 && !pgdat_balanced(pgdat, order, *classzone_idx)); out: -- 1.8.1.4 -- 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/ . Don't email: email@kvack.org