From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09B88C07EBF for ; Fri, 18 Jan 2019 17:53:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF84D20850 for ; Fri, 18 Jan 2019 17:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728855AbfARRxK (ORCPT ); Fri, 18 Jan 2019 12:53:10 -0500 Received: from outbound-smtp13.blacknight.com ([46.22.139.230]:55130 "EHLO outbound-smtp13.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728426AbfARRxK (ORCPT ); Fri, 18 Jan 2019 12:53:10 -0500 Received: from mail.blacknight.com (unknown [81.17.254.16]) by outbound-smtp13.blacknight.com (Postfix) with ESMTPS id 7EC9B1C35AC for ; Fri, 18 Jan 2019 17:53:08 +0000 (GMT) Received: (qmail 2023 invoked from network); 18 Jan 2019 17:53:08 -0000 Received: from unknown (HELO stampy.163woodhaven.lan) (mgorman@techsingularity.net@[37.228.229.96]) by 81.17.254.9 with ESMTPA; 18 Jan 2019 17:53:08 -0000 From: Mel Gorman To: Andrew Morton Cc: David Rientjes , Andrea Arcangeli , Vlastimil Babka , Linux List Kernel Mailing , Linux-MM , Mel Gorman Subject: [PATCH 08/22] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Date: Fri, 18 Jan 2019 17:51:22 +0000 Message-Id: <20190118175136.31341-9-mgorman@techsingularity.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190118175136.31341-1-mgorman@techsingularity.net> References: <20190118175136.31341-1-mgorman@techsingularity.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When pageblocks get fragmented, watermarks are artifically boosted to reclaim pages to avoid further fragmentation events. However, compaction is often either fragmentation-neutral or moving movable pages away from unmovable/reclaimable pages. As the true watermarks are preserved, allow compaction to ignore the boost factor. The expected impact is very slight as the main benefit is that compaction is slightly more likely to succeed when the system has been fragmented very recently. On both 1-socket and 2-socket machines for THP-intensive allocation during fragmentation the success rate was increased by less than 1% which is marginal. However, detailed tracing indicated that failure of migration due to a premature ENOMEM triggered by watermark checks were eliminated. Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index fc769ff4fb2c..6607cb7131b0 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3071,7 +3071,7 @@ int __isolate_free_page(struct page *page, unsigned int order) * watermark, because we already know our high-order page * exists. */ - watermark = min_wmark_pages(zone) + (1UL << order); + watermark = zone->_watermark[WMARK_MIN] + (1UL << order); if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA)) return 0; -- 2.16.4