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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0B197C4708C for ; Fri, 28 May 2021 11:08:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D574C613D1 for ; Fri, 28 May 2021 11:08:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235902AbhE1LKS (ORCPT ); Fri, 28 May 2021 07:10:18 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:40776 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234367AbhE1LKP (ORCPT ); Fri, 28 May 2021 07:10:15 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 4811B1FD2F; Fri, 28 May 2021 11:08:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1622200120; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=S+LF2PVwb9H16A2qGrmXbe0U4IHpiocrNiUK5mO4Lj0=; b=IG0o2uF1HpWlHTL+sOO1My7E4FRBxsbU6q0T7So4RWZTdvD0pvcMB2JMnwF6MlzLVQ/L/c Lsg3GwEyjIqV4kIyienHZ9YxJG/mevLBOI4hGliuncZDL9dqIYah/LfIX+2H8AmWwJjIuN kjbmkhU241otF0hpt037du1N8zMpz5U= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1622200120; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=S+LF2PVwb9H16A2qGrmXbe0U4IHpiocrNiUK5mO4Lj0=; b=GLqI1FaG6tIxtN65cGlnSTIFKdjiZYcj3Vw32L3yeXF+TnAxknWmsvjrTZaS8v/6UC364t 85jmhX/Ba4/u3SAg== Received: from director2.suse.de (director2.suse-dmz.suse.de [192.168.254.72]) by imap.suse.de (Postfix) with ESMTPSA id 3376711A98; Fri, 28 May 2021 11:08:40 +0000 (UTC) Subject: Re: [PATCH 3/6] mm/page_alloc: Adjust pcp->high after CPU hotplug events To: Mel Gorman , Andrew Morton Cc: Hillf Danton , Dave Hansen , Michal Hocko , LKML , Linux-MM References: <20210525080119.5455-1-mgorman@techsingularity.net> <20210525080119.5455-4-mgorman@techsingularity.net> From: Vlastimil Babka Message-ID: <7b457a8b-877b-1644-9709-68a67cd27b60@suse.cz> Date: Fri, 28 May 2021 13:08:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <20210525080119.5455-4-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/25/21 10:01 AM, Mel Gorman wrote: > The PCP high watermark is based on the number of online CPUs so the > watermarks must be adjusted during CPU hotplug. At the time of > hot-remove, the number of online CPUs is already adjusted but during > hot-add, a delta needs to be applied to update PCP to the correct > value. After this patch is applied, the high watermarks are adjusted > correctly. > > # grep high: /proc/zoneinfo | tail -1 > high: 649 > # echo 0 > /sys/devices/system/cpu/cpu4/online > # grep high: /proc/zoneinfo | tail -1 > high: 664 > # echo 1 > /sys/devices/system/cpu/cpu4/online > # grep high: /proc/zoneinfo | tail -1 > high: 649 > > Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka