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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7BA7DC43381 for ; Fri, 26 Feb 2021 01:17:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 374B564F17 for ; Fri, 26 Feb 2021 01:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229492AbhBZBRa (ORCPT ); Thu, 25 Feb 2021 20:17:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:48526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229863AbhBZBRT (ORCPT ); Thu, 25 Feb 2021 20:17:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2518064F13; Fri, 26 Feb 2021 01:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614302215; bh=aERu7B+meUjS1DkaQS6FJmelVfnIKPgjL4xkn8mlZps=; h=Date:From:To:Subject:In-Reply-To:From; b=h2wVN3HuHinsxkkc8J580tB8AfyKbORrRKdsBG+FmPI5ub3WMY91YezHdnXWgp9mL wNPd0q0EXHWEmSGwzkyM3WA8labhSW1RsAtAgVTEEXM6N0ugd5uXXFl81iHvxDJ4LU Zh7Uifm1yMwhrLnK7Bgh0v/A4QdCIHnc8U2AlmuQ= Date: Thu, 25 Feb 2021 17:16:54 -0800 From: Andrew Morton To: akpm@linux-foundation.org, benbjiang@tencent.com, cl@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, robinlai@tencent.com, torvalds@linux-foundation.org Subject: [patch 025/118] mm/vmstat.c: erase latency in vmstat_shepherd Message-ID: <20210226011654.UO7WPPOjW%akpm@linux-foundation.org> In-Reply-To: <20210225171452.713967e96554bb6a53e44a19@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Jiang Biao Subject: mm/vmstat.c: erase latency in vmstat_shepherd Many 100us+ latencies have been deteceted in vmstat_shepherd() on CPX platform which has 208 logic cpus. And vmstat_shepherd is queued every second, which could make the case worse. Add schedule point in vmstat_shepherd() to erase the latency. Link: https://lkml.kernel.org/r/20210111035526.1511-1-benbjiang@tencent.com Signed-off-by: Jiang Biao Reported-by: Bin Lai Cc: Christoph Lameter Signed-off-by: Andrew Morton --- mm/vmstat.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/vmstat.c~mm-vmstatc-erase-latency-in-vmstat_shepherd +++ a/mm/vmstat.c @@ -1980,6 +1980,8 @@ static void vmstat_shepherd(struct work_ if (!delayed_work_pending(dw) && need_update(cpu)) queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0); + + cond_resched(); } put_online_cpus(); _