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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 D9DB6C43465 for ; Fri, 18 Sep 2020 07:32:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 889AD2076D for ; Fri, 18 Sep 2020 07:32:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=suse.com header.i=@suse.com header.b="XZPvSCfL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726744AbgIRHco (ORCPT ); Fri, 18 Sep 2020 03:32:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:35026 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726040AbgIRHco (ORCPT ); Fri, 18 Sep 2020 03:32:44 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=cantorsusede; t=1600414361; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=WgNBJtQybUt+aLQlWkB/4yJbkuXmXsDcz8/9t/Jw7us=; b=XZPvSCfLPNA9NPNZeW8OYl6SToHj1z2xudwJVjZarJ7zPWa3KAYW8zHxkryTkcv5ODNrM0 ujQQWcWMcG2b0KnHXk4BBGf3m6TmFQ4LUmA/VHvnMeSW2WmwnJRm/qFCfpGIM0yLShH9Ag dg17dOnjgp5v/gDFEKAdstA6Hz64b87yp3A+mn8ydYeOnCGqXFTHSgwokBUHtazJ//CzBM xvGf5k80AoNDvkK444ScJqOSO9PygCAYTYTprw4jf9xKPnM/iJkGi3ALe9PGkLuornjOYZ JG2Dl/E40rf/W2NnBUgud+kZ7HTs3noIos5cYQyghtXmVWeukJvCyw4+aqY4Xg== Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C618FAD79; Fri, 18 Sep 2020 07:33:15 +0000 (UTC) Date: Fri, 18 Sep 2020 09:32:40 +0200 From: Michal Hocko To: Yu Zhao Cc: Andrew Morton , Alex Shi , Steven Rostedt , Ingo Molnar , Johannes Weiner , Vladimir Davydov , Roman Gushchin , Shakeel Butt , Chris Down , Yafang Shao , Vlastimil Babka , Huang Ying , Pankaj Gupta , Matthew Wilcox , Konstantin Khlebnikov , Minchan Kim , Jaewon Kim , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/13] mm: use add_page_to_lru_list() Message-ID: <20200918073240.GD28827@dhcp22.suse.cz> References: <20200918030051.650890-1-yuzhao@google.com> <20200918030051.650890-2-yuzhao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918030051.650890-2-yuzhao@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 17-09-20 21:00:39, Yu Zhao wrote: > This patch replaces the only open-coded lru list addition with > add_page_to_lru_list(). > > Before this patch, we have: > update_lru_size() > list_move() > > After this patch, we have: > list_del() > add_page_to_lru_list() > update_lru_size() > list_add() > > The only side effect is that page->lru is temporarily poisoned > after a page is deleted from its old list, which shouldn't be a > problem. "because the lru lock is held" right? Please always be explicit about your reasoning. "It shouldn't be a problem" without further justification is just pointless for anybody reading the code later on. > Signed-off-by: Yu Zhao > --- > mm/vmscan.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 9727dd8e2581..503fc5e1fe32 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1850,8 +1850,8 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, > while (!list_empty(list)) { > page = lru_to_page(list); > VM_BUG_ON_PAGE(PageLRU(page), page); > + list_del(&page->lru); > if (unlikely(!page_evictable(page))) { > - list_del(&page->lru); > spin_unlock_irq(&pgdat->lru_lock); > putback_lru_page(page); > spin_lock_irq(&pgdat->lru_lock); > @@ -1862,9 +1862,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, > SetPageLRU(page); > lru = page_lru(page); > > - nr_pages = thp_nr_pages(page); > - update_lru_size(lruvec, lru, page_zonenum(page), nr_pages); > - list_move(&page->lru, &lruvec->lists[lru]); > + add_page_to_lru_list(page, lruvec, lru); > > if (put_page_testzero(page)) { > __ClearPageLRU(page); > @@ -1878,6 +1876,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, > } else > list_add(&page->lru, &pages_to_free); > } else { > + nr_pages = thp_nr_pages(page); > nr_moved += nr_pages; > if (PageActive(page)) > workingset_age_nonresident(lruvec, nr_pages); > -- > 2.28.0.681.g6f77f65b4e-goog -- Michal Hocko SUSE Labs