From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753573Ab2GWNjB (ORCPT ); Mon, 23 Jul 2012 09:39:01 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58633 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325Ab2GWNiy (ORCPT ); Mon, 23 Jul 2012 09:38:54 -0400 From: Mel Gorman To: Stable Cc: Linux-MM , LKML , Mel Gorman Subject: [PATCH 09/34] mm: limit direct reclaim for higher order allocations Date: Mon, 23 Jul 2012 14:38:22 +0100 Message-Id: <1343050727-3045-10-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1343050727-3045-1-git-send-email-mgorman@suse.de> References: <1343050727-3045-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rik van Riel commit e0887c19b2daa140f20ca8104bdc5740f39dbb86 upstream. Stable note: Not tracked on Bugzilla. THP and compaction was found to aggressively reclaim pages and stall systems under different situations that was addressed piecemeal over time. Paragraph 3 of this changelog is the motivation for this patch. When suffering from memory fragmentation due to unfreeable pages, THP page faults will repeatedly try to compact memory. Due to the unfreeable pages, compaction fails. Needless to say, at that point page reclaim also fails to create free contiguous 2MB areas. However, that doesn't stop the current code from trying, over and over again, and freeing a minimum of 4MB (2UL << sc->order pages) at every single invocation. This resulted in my 12GB system having 2-3GB free memory, a corresponding amount of used swap and very sluggish response times. This can be avoided by having the direct reclaim code not reclaim from zones that already have plenty of free memory available for compaction. If compaction still fails due to unmovable memory, doing additional reclaim will only hurt the system, not help. [jweiner@redhat.com: change comment to explain the order check] Signed-off-by: Rik van Riel Acked-by: Johannes Weiner Cc: Andrea Arcangeli Reviewed-by: Minchan Kim Signed-off-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman --- mm/vmscan.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index 8ca1cd5..d11b6c4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2059,6 +2059,22 @@ static void shrink_zones(int priority, struct zonelist *zonelist, continue; if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* Let kswapd poll it */ + if (COMPACTION_BUILD) { + /* + * If we already have plenty of memory + * free for compaction, don't free any + * more. Even though compaction is + * invoked for any non-zero order, + * only frequent costly order + * reclamation is disruptive enough to + * become a noticable problem, like + * transparent huge page allocations. + */ + if (sc->order > PAGE_ALLOC_COSTLY_ORDER && + (compaction_suitable(zone, sc->order) || + compaction_deferred(zone))) + continue; + } /* * This steals pages from memory cgroups over softlimit * and returns the number of reclaimed pages and -- 1.7.9.2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx124.postini.com [74.125.245.124]) by kanga.kvack.org (Postfix) with SMTP id A84E76B0070 for ; Mon, 23 Jul 2012 09:38:55 -0400 (EDT) From: Mel Gorman Subject: [PATCH 09/34] mm: limit direct reclaim for higher order allocations Date: Mon, 23 Jul 2012 14:38:22 +0100 Message-Id: <1343050727-3045-10-git-send-email-mgorman@suse.de> In-Reply-To: <1343050727-3045-1-git-send-email-mgorman@suse.de> References: <1343050727-3045-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Stable Cc: Linux-MM , LKML , Mel Gorman From: Rik van Riel commit e0887c19b2daa140f20ca8104bdc5740f39dbb86 upstream. Stable note: Not tracked on Bugzilla. THP and compaction was found to aggressively reclaim pages and stall systems under different situations that was addressed piecemeal over time. Paragraph 3 of this changelog is the motivation for this patch. When suffering from memory fragmentation due to unfreeable pages, THP page faults will repeatedly try to compact memory. Due to the unfreeable pages, compaction fails. Needless to say, at that point page reclaim also fails to create free contiguous 2MB areas. However, that doesn't stop the current code from trying, over and over again, and freeing a minimum of 4MB (2UL << sc->order pages) at every single invocation. This resulted in my 12GB system having 2-3GB free memory, a corresponding amount of used swap and very sluggish response times. This can be avoided by having the direct reclaim code not reclaim from zones that already have plenty of free memory available for compaction. If compaction still fails due to unmovable memory, doing additional reclaim will only hurt the system, not help. [jweiner@redhat.com: change comment to explain the order check] Signed-off-by: Rik van Riel Acked-by: Johannes Weiner Cc: Andrea Arcangeli Reviewed-by: Minchan Kim Signed-off-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman --- mm/vmscan.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index 8ca1cd5..d11b6c4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2059,6 +2059,22 @@ static void shrink_zones(int priority, struct zonelist *zonelist, continue; if (zone->all_unreclaimable && priority != DEF_PRIORITY) continue; /* Let kswapd poll it */ + if (COMPACTION_BUILD) { + /* + * If we already have plenty of memory + * free for compaction, don't free any + * more. Even though compaction is + * invoked for any non-zero order, + * only frequent costly order + * reclamation is disruptive enough to + * become a noticable problem, like + * transparent huge page allocations. + */ + if (sc->order > PAGE_ALLOC_COSTLY_ORDER && + (compaction_suitable(zone, sc->order) || + compaction_deferred(zone))) + continue; + } /* * This steals pages from memory cgroups over softlimit * and returns the number of reclaimed pages and -- 1.7.9.2 -- 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/ . Don't email: email@kvack.org