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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 8EFC6C433ED for ; Sat, 3 Apr 2021 12:37:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CC6046121F for ; Sat, 3 Apr 2021 12:37:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC6046121F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 590876B0071; Sat, 3 Apr 2021 08:37:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 565CA6B0075; Sat, 3 Apr 2021 08:37:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 430CC6B0078; Sat, 3 Apr 2021 08:37:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 271646B0071 for ; Sat, 3 Apr 2021 08:37:56 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id DA17918488BDC for ; Sat, 3 Apr 2021 12:37:55 +0000 (UTC) X-FDA: 77991007710.39.D0AF1E0 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by imf01.hostedemail.com (Postfix) with ESMTP id BC58F5001526 for ; Sat, 3 Apr 2021 12:37:53 +0000 (UTC) Received: by mail-pl1-f171.google.com with SMTP id ay2so3638217plb.3 for ; Sat, 03 Apr 2021 05:37:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3znEsRlGP0N8fSB0MyPPdnv2DM9lRQ51vAjGcVokwdg=; b=wcY4VKKuD29nmfwYrc2MSjfDEufxBo6ateTTtXPw2mWsv4qKh8DHBWzrJbb42qGyx9 tHDp5FrvWIESUQKiRlcTtc+QvWT80uq+FOcdaS6pOriq2VnDFYp71IBu3s17U09xO/aL +oLFDW7T5+l9hEHzmXGd7AWajtoh1Te/3bEI7fMEiXazVlSYIWf4q2vDnv2hoaYRJwz+ vZMcrVQBzVNnKRfAYXiVQVuZ/27KAZXiJxBiFjdrF+iG7SwgxsIzHX9sCfR3puObgQZ6 CQfVA3bIFHZ/PASoqHkgzMDOATWEEkJOLCvLTdQSA69bie8e4RAgQ2biUS/BRBLf51gm G82Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3znEsRlGP0N8fSB0MyPPdnv2DM9lRQ51vAjGcVokwdg=; b=Cv61soHm6EcueVwbP0T12oSMlS3imPVRwKCHUyLM4O+fs8npMcaUzF3aeEAKOT2xlY Yj0TlbDj4O8zxiSlSQ6X6U5pEH4HYaN1YqoI4b3L0rfR+Pc1gWiqRdW3Ej5lwuFiNaC2 FWDEd3MgSZFGjM6cCicOdVokGUfAMxAy37ww5APf8PenqF7eJ6gnuHxo26zgDBBfDfUb f67tBmt9QDFJxlJzNkdqWKUxfqaUnZATCUggAp9SYyKxi0Z0QvEtVlusm9N7c+LjKE4L BSY/HnGfsEqDroBPasBrC1wKwL/dhyG2FkT7Hm9n6oWkAjWb7u/oup4AXpxQHkxzIWTy oE6Q== X-Gm-Message-State: AOAM533fCfG0KxEQ3SgHNosd+BI1W0GEQC0OWCKRM06v4F+PexVnwZeE pa5QUV/FfiQxOnrIEeHO6WtcW0g9Tz7JDDl5ebuW/Q== X-Google-Smtp-Source: ABdhPJxy2yRuBIGJm+2kp2+JUFXvhF8YEcntMLHSjum5mCfeO9d5gq1hLYRoZtEDGiqEuIhm07Norq+7E1pHt5Wp0Y8= X-Received: by 2002:a17:90b:14f:: with SMTP id em15mr5218709pjb.13.1617453472928; Sat, 03 Apr 2021 05:37:52 -0700 (PDT) MIME-Version: 1.0 References: <20210330101531.82752-1-songmuchun@bytedance.com> <20210330101531.82752-5-songmuchun@bytedance.com> In-Reply-To: From: Muchun Song Date: Sat, 3 Apr 2021 20:37:14 +0800 Message-ID: Subject: Re: [External] Re: [RFC PATCH 04/15] mm: memcontrol: use lruvec_memcg in lruvec_holds_page_lru_lock To: Johannes Weiner Cc: Roman Gushchin , Michal Hocko , Andrew Morton , Shakeel Butt , Vladimir Davydov , LKML , Linux Memory Management List , Xiongchun duan , Hugh Dickins Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: BC58F5001526 X-Stat-Signature: etyjjk5k7askjoz7prz5y9kjm83yficj Received-SPF: none (bytedance.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=mail-pl1-f171.google.com; client-ip=209.85.214.171 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617453473-412053 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Apr 3, 2021 at 12:21 AM Johannes Weiner wrote: > > On Tue, Mar 30, 2021 at 06:15:20PM +0800, Muchun Song wrote: > > We already have a helper lruvec_memcg() to get the memcg from lruvec, we > > do not need to do it ourselves in the lruvec_holds_page_lru_lock(). So use > > lruvec_memcg() instead. > > > > Signed-off-by: Muchun Song > > --- > > include/linux/memcontrol.h | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > index a35a22994cf7..6e3283828391 100644 > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -744,20 +744,20 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page) > > return mem_cgroup_lruvec(memcg, pgdat); > > } > > > > +static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec); > > Please reorder the functions instead to avoid forward decls. OK. Will fix it in the next version. > > > static inline bool lruvec_holds_page_lru_lock(struct page *page, > > struct lruvec *lruvec) > > { > > pg_data_t *pgdat = page_pgdat(page); > > const struct mem_cgroup *memcg; > > - struct mem_cgroup_per_node *mz; > > > > if (mem_cgroup_disabled()) > > return lruvec == &pgdat->__lruvec; > > > > - mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec); > > memcg = page_memcg(page) ? : root_mem_cgroup; > > > > - return lruvec->pgdat == pgdat && mz->memcg == memcg; > > + return lruvec->pgdat == pgdat && lruvec_memcg(lruvec) == memcg; > > Looks reasonable to me, but I wonder if there is more we can do. > > lruvec_memcg() already handles CONFIG_MEMCG and mem_cgroup_disabled() > combinations, and there is also a lruvec_pgdat() which does. > > One thing that is odd is page_memcg(page) ? : root_mem_cgroup. How can > lruvec pages not have a page_memcg()? mem_cgroup_page_lruvec() has: You are right. page_memcg() cannot be NULL. > > memcg = page_memcg(page); > VM_WARN_ON_ONCE_PAGE(!memcg && !mem_cgroup_disabled(), page); > > Unless I'm missing something, we should be able to have a single > definition for this function that works for !CONFIG_MEMCG, > CONFIG_MEMCG + mem_cgroup_disabled() and CONFIG_MEMCG: > > lruvec_holds_page_lru_lock() > { > return lruvec_pgdat(lruvec) == page_pgdat(page) && > lruvec_memcg(lruvec) == page_memcg(page); > } Aha, how wonderful! It is simpler than mine. I will use this. Thanks for your suggestions.