From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 588B56B0055 for ; Thu, 12 Feb 2009 06:51:56 -0500 (EST) Message-Id: <20090212114416.197688682@cmpxchg.org> Date: Thu, 12 Feb 2009 12:36:11 +0100 From: Johannes Weiner Subject: [patch 2/2] vmscan: clip swap_cluster_max in shrink_all_memory() References: <20090212113609.351980834@cmpxchg.org> Content-Disposition: inline; filename=vmscan-clip-swap_cluster_max-in-shrink_all_memory.patch Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: KOSAKI Motohiro , MinChan Kim , "Rafael J. Wysocki" , Nigel Cunningham , Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: shrink_inactive_list() scans in sc->swap_cluster_max chunks until it hits the scan limit it was passed. shrink_inactive_list() { do { isolate_pages(swap_cluster_max) shrink_page_list() } while (nr_scanned < max_scan); } This assumes that swap_cluster_max is not bigger than the scan limit because the latter is checked only after at least one iteration. In shrink_all_memory() sc->swap_cluster_max is initialized to the overall reclaim goal in the beginning but not decreased while reclaim is making progress which leads to subsequent calls to shrink_inactive_list() reclaiming way too much in the one iteration that is done unconditionally. Set sc->swap_cluster_max always to the proper goal before doing shrink_all_zones() shrink_list() shrink_inactive_list(). While the current shrink_all_memory() happily reclaims more than actually requested, this patch fixes it to never exceed the goal: unpatched wanted=10000 reclaimed=13356 wanted=10000 reclaimed=19711 wanted=10000 reclaimed=10289 wanted=10000 reclaimed=17306 wanted=10000 reclaimed=10700 wanted=10000 reclaimed=10004 wanted=10000 reclaimed=13301 wanted=10000 reclaimed=10976 wanted=10000 reclaimed=10605 wanted=10000 reclaimed=10088 wanted=10000 reclaimed=15000 patched wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9599 wanted=10000 reclaimed=8476 wanted=10000 reclaimed=8326 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9919 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=9624 wanted=10000 reclaimed=10000 wanted=10000 reclaimed=10000 wanted=8500 reclaimed=8092 wanted=316 reclaimed=316 Signed-off-by: Johannes Weiner Cc: KOSAKI Motohiro Cc: MinChan Kim Cc: "Rafael J. Wysocki" Cc: Nigel Cunningham Cc: Rik van Riel --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2105,7 +2105,6 @@ unsigned long shrink_all_memory(unsigned struct scan_control sc = { .gfp_mask = GFP_KERNEL, .may_unmap = 0, - .swap_cluster_max = nr_pages, .may_writepage = 1, .isolate_pages = isolate_pages_global, }; @@ -2147,6 +2146,7 @@ unsigned long shrink_all_memory(unsigned unsigned long nr_to_scan = nr_pages - sc.nr_reclaimed; sc.nr_scanned = 0; + sc.swap_cluster_max = nr_to_scan; shrink_all_zones(nr_to_scan, prio, pass, &sc); if (sc.nr_reclaimed >= nr_pages) goto out; -- 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