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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 E9AABC3F2D1 for ; Mon, 2 Mar 2020 22:11:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B1BFF2173E for ; Mon, 2 Mar 2020 22:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583187107; bh=nmmuEpxmCjc0aKsztvjVXQXja7/rg6W/P3XUJuNzzKc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Up9PfCD+COo57b/pfmN9tYtesVKdBxP17Gqc1DnYPwNJxrQGKvA/RppnIxOwy3rov yMkP8654DXjhCjKgD+ExTKx/nzA9XM0Ntzh9O94UccAH6Ak84KZT3w0qTE3CnA+Drk EOu4/zuDL3MyHuvbLL/jwCdibbAJ+E0gl+wgxZ4g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726843AbgCBWLq (ORCPT ); Mon, 2 Mar 2020 17:11:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:35186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725781AbgCBWLq (ORCPT ); Mon, 2 Mar 2020 17:11:46 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 46D4921739; Mon, 2 Mar 2020 22:11:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583187105; bh=nmmuEpxmCjc0aKsztvjVXQXja7/rg6W/P3XUJuNzzKc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=0q18elEUkRaxUtioBVBS0syNq3bikiyHmmqzQeYjY9AB/5R2JiOBn5bl54IyRZzmt nLXzchT4MCXx8AoVjhcjC4USN/LyuG9qHeJn15K86f757YVqpUM0rb9wmH5F0hqdSj AWBD+bnAAE4uWywcgoAr66YGhiWsV1IXA2regTt8= Date: Mon, 2 Mar 2020 14:11:44 -0800 From: Andrew Morton To: Alex Shi Cc: cgroups@vger.kernel.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, Michal Hocko , Vladimir Davydov , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU Message-Id: <20200302141144.b30abe0d89306fd387e13a92@linux-foundation.org> In-Reply-To: <1583146830-169516-8-git-send-email-alex.shi@linux.alibaba.com> References: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com> <1583146830-169516-8-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2 Mar 2020 19:00:17 +0800 Alex Shi wrote: > Combined PageLRU check and ClearPageLRU into one function by new > introduced func TestClearPageLRU. This function will be used as page > isolation precondition. > > No functional change yet. > > ... > > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2588,9 +2588,8 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg, > pgdat = page_pgdat(page); > spin_lock_irq(&pgdat->lru_lock); > > - if (PageLRU(page)) { > + if (TestClearPageLRU(page)) { > lruvec = mem_cgroup_page_lruvec(page, pgdat); > - ClearPageLRU(page); > del_page_from_lru_list(page, lruvec, page_lru(page)); > } else The code will now get exclusive access of the page->flags cacheline and will dirty that cacheline, even for !PageLRU() pages. What is the performance impact of this?