From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754405AbcEJAGc (ORCPT ); Mon, 9 May 2016 20:06:32 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57699 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754360AbcEJAG0 (ORCPT ); Mon, 9 May 2016 20:06:26 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Hugh Dickins , Vlastimil Babka , Michal Hocko , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 45/54] mm, cma: prevent nr_isolated_* counters from going negative Date: Mon, 9 May 2016 17:05:04 -0700 Message-Id: <1462838713-31343-46-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1462838713-31343-1-git-send-email-kamal@canonical.com> References: <1462838713-31343-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt21 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Hugh Dickins commit 14af4a5e9b26ad251f81c174e8a43f3e179434a5 upstream. /proc/sys/vm/stat_refresh warns nr_isolated_anon and nr_isolated_file go increasingly negative under compaction: which would add delay when should be none, or no delay when should delay. The bug in compaction was due to a recent mmotm patch, but much older instance of the bug was also noticed in isolate_migratepages_range() which is used for CMA and gigantic hugepage allocations. The bug is caused by putback_movable_pages() in an error path decrementing the isolated counters without them being previously incremented by acct_isolated(). Fix isolate_migratepages_range() by removing the error-path putback, thus reaching acct_isolated() with migratepages still isolated, and leaving putback to caller like most other places do. Fixes: edc2ca612496 ("mm, compaction: move pageblock checks up from isolate_migratepages_range()") [vbabka@suse.cz: expanded the changelog] Signed-off-by: Hugh Dickins Signed-off-by: Vlastimil Babka Acked-by: Joonsoo Kim Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- mm/compaction.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 91357ff..3958143 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -781,16 +781,8 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, pfn = isolate_migratepages_block(cc, pfn, block_end_pfn, ISOLATE_UNEVICTABLE); - /* - * In case of fatal failure, release everything that might - * have been isolated in the previous iteration, and signal - * the failure back to caller. - */ - if (!pfn) { - putback_movable_pages(&cc->migratepages); - cc->nr_migratepages = 0; + if (!pfn) break; - } if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) break; -- 2.7.4