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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 2595CC28CF6 for ; Fri, 3 Aug 2018 11:25:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DDC9821761 for ; Fri, 3 Aug 2018 11:25:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DDC9821761 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727647AbeHCNU6 (ORCPT ); Fri, 3 Aug 2018 09:20:58 -0400 Received: from mga03.intel.com ([134.134.136.65]:9685 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726933AbeHCNU5 (ORCPT ); Fri, 3 Aug 2018 09:20:57 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Aug 2018 04:25:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,438,1526367600"; d="scan'208";a="62107286" Received: from devel-ww.sh.intel.com ([10.239.48.110]) by orsmga008.jf.intel.com with ESMTP; 03 Aug 2018 04:25:02 -0700 From: Wei Wang To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, penguin-kernel@I-love.SAKURA.ne.jp, chris@chris-wilson.co.uk, mst@redhat.com Cc: wei.w.wang@intel.com Subject: [PATCH] mm/vmscan: adjust shrinkctl->nr_scanned after invoking scan_objects Date: Fri, 3 Aug 2018 18:56:49 +0800 Message-Id: <1533293809-34354-1-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some shrinkers may free more than the requested nr_to_scan of pages in one invocation of scan_objects, and some may free less than that. Currently shrinkers can either return the actual number of pages that have been freed via the return value of scan_objects or track that actual number in shrinkctl->nr_scanned. But do_shrink_slab works on an assumption that the actual number is always tracked via shrinkctl->nr_scanned, which is not true. Having checked the shrinkers used in the kernel, they basically return the actual number of freed pages via the return value of scan_objects, and most of them leave shrinkctl->nr_scanned unchanged after scan_objects is called. So this patch adjusts shrinkctl->nr_scanned to the actual freed number after scan_objects is called. Signed-off-by: Wei Wang Cc: Michal Hocko Cc: Andrew Morton Cc: Tetsuo Handa Cc: Chris Wilson Cc: Michael S. Tsirkin --- mm/vmscan.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 03822f8..78a75b9 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -447,9 +447,13 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, if (ret == SHRINK_STOP) break; freed += ret; + shrinkctl->nr_scanned = ret; count_vm_events(SLABS_SCANNED, shrinkctl->nr_scanned); - total_scan -= shrinkctl->nr_scanned; + if (total_scan > shrinkctl->nr_scanned) + total_scan -= shrinkctl->nr_scanned; + else + total_scan = 0; scanned += shrinkctl->nr_scanned; cond_resched(); -- 2.7.4