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=-10.1 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 2A852C43463 for ; Fri, 18 Sep 2020 09:37:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6D4321D42 for ; Fri, 18 Sep 2020 09:37:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726448AbgIRJhw (ORCPT ); Fri, 18 Sep 2020 05:37:52 -0400 Received: from mx2.suse.de ([195.135.220.15]:43836 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726109AbgIRJhw (ORCPT ); Fri, 18 Sep 2020 05:37:52 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 818A5AE4B; Fri, 18 Sep 2020 09:38:25 +0000 (UTC) Subject: Re: [RFC 3/5] mm, page_alloc(): remove setup_pageset() To: Oscar Salvador Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , Pavel Tatashin , David Hildenbrand , Joonsoo Kim References: <20200907163628.26495-1-vbabka@suse.cz> <20200907163628.26495-4-vbabka@suse.cz> <20200910092307.GD2285@linux> From: Vlastimil Babka Message-ID: <2c38b1f8-4e60-39f8-66c7-c0bbdb9df3cc@suse.cz> Date: Fri, 18 Sep 2020 11:37:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200910092307.GD2285@linux> 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 9/10/20 11:23 AM, Oscar Salvador wrote: > On Mon, Sep 07, 2020 at 06:36:26PM +0200, Vlastimil Babka wrote: >> We initialize boot-time pagesets with setup_pageset(), which sets high and >> batch values that effectively disable pcplists. >> >> We can remove this wrapper if we just set these values for all pagesets in >> pageset_init(). Non-boot pagesets then subsequently update them to specific >> values. >> >> Signed-off-by: Vlastimil Babka > > Reviewed-by: Oscar Salvador Thanks! > Just one question below: > >> -static void setup_pageset(struct per_cpu_pageset *p) >> -{ >> - pageset_init(p); >> - pageset_update(&p->pcp, 0, 1); >> + /* >> + * Set batch and high values safe for a boot pageset. Proper pageset's >> + * initialization will update them. >> + */ >> + pcp->high = 0; >> + pcp->batch = 1; > > pageset_update was manipulating these values with barriers in between. > I guess we do not care here because we are not really updating but > initializing them, right? Sure. We just initialized all the list heads, so there can be no concurrent access at this point. But I'll mention it in the comment.