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=-13.8 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 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 ADBE7C433B4 for ; Wed, 14 Apr 2021 10:01:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7CB59613B1 for ; Wed, 14 Apr 2021 10:01:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348750AbhDNKBq (ORCPT ); Wed, 14 Apr 2021 06:01:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348630AbhDNKBm (ORCPT ); Wed, 14 Apr 2021 06:01:42 -0400 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95529C061574 for ; Wed, 14 Apr 2021 03:01:20 -0700 (PDT) Received: by mail-pf1-x42c.google.com with SMTP id a85so12949953pfa.0 for ; Wed, 14 Apr 2021 03:01:20 -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=oM3UOkNCezMjiEPLSqbUtWwjwRir2sVI9CJStf2+Is4=; b=rhjv0ZuhAtazcQOUb1eJY2IvHwhZz1bA7N5PVM7o+aT3T25vyS1PN1mUU95ATPaBJI RY4cIBkIz/v9jbeC5/v6bu7jA1MTxYH4qdNO711e1r4WGTO9f0QJ19Qf92GiIJ7t1AWr lG63XrIx+2T5RudUiNV8oJCo/XgdvvbFsIRMrgSVY26lj21qBW5Gmw6za+cdJAlHbDYF 2SFsx6EqyAPN0PNGUvt7qOKIJ+GW+jCP4jcGD6gJzoifIImbyjlnYjd/0J1o/sotiIID QqkvZdB6+VJYJzidr27YDCwhZkMg6R85+nbBYhpwYLHOBZeongYye/eP0fyXY3+kET50 BPeA== 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=oM3UOkNCezMjiEPLSqbUtWwjwRir2sVI9CJStf2+Is4=; b=WZxZEgd2x9EoC0O4RG22r0WU3TCNKdyuJ2MhYMvOYH9J1Jd75fo4NwHXy8Mr2RfXoJ /J0j3nJKLc8KPTRWoPnGH+1EBsShJvjg7Uaf70ps+Jre5sAOmJu35TFaZEu5fyrCPmyB q0LtGtmFrSqvryZ/O24rWExKdPjH7z3vGMeyMaj6gOU/Ggyrj7ioGNNxPuPOsJjaO57g 2WQnsdtTsj4yw1RFSgbcKbvs0hOmD07szzKzLElm81c0pPrhYOdYKbqr4WrRME0ox63A y7GU+2nnqRSEj7ka8wmUpRYlsentKRQb2VomKeH5E5pLh/XuFj5FdhxiscFVWLBGk9zF fbvQ== X-Gm-Message-State: AOAM530eWFVEPBFzcPYtgDq5cZwtMPs5V+iIQsRfn6rZUEH6DCPqsmez EHUGg2HCoDbAiCqTImF0hDdrg+PyjODPIsdP9lls5A== X-Google-Smtp-Source: ABdhPJx/Xz6/Qy9p2feD9c2q71a08v4/irn/LoCKOc74pl8CFJ99bxidUCILsasl29hfhSjf0g3N3T8C9CnEV4405Ag= X-Received: by 2002:aa7:950d:0:b029:244:4dd5:cd0a with SMTP id b13-20020aa7950d0000b02902444dd5cd0amr29593080pfp.59.1618394480009; Wed, 14 Apr 2021 03:01:20 -0700 (PDT) MIME-Version: 1.0 References: <20210413065153.63431-1-songmuchun@bytedance.com> <20210413065153.63431-5-songmuchun@bytedance.com> In-Reply-To: From: Muchun Song Date: Wed, 14 Apr 2021 18:00:42 +0800 Message-ID: Subject: Re: [External] Re: [PATCH 4/7] mm: memcontrol: simplify lruvec_holds_page_lru_lock To: Michal Hocko Cc: guro@fb.com, hannes@cmpxchg.org, akpm@linux-foundation.org, shakeelb@google.com, vdavydov.dev@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, fam.zheng@bytedance.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 14, 2021 at 5:44 PM Michal Hocko wrote: > > On Tue 13-04-21 14:51:50, 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. And if mem_cgroup_disabled() returns false, the > > page_memcg(page) (the LRU pages) cannot be NULL. So remove the odd logic > > of "memcg = page_memcg(page) ? : root_mem_cgroup". And use lruvec_pgdat > > to simplify the code. We can have a single definition for this function > > that works for !CONFIG_MEMCG, CONFIG_MEMCG + mem_cgroup_disabled() and > > CONFIG_MEMCG. > > Neat. While you are at it wouldn't it make sesne to rename the function > as well. I do not want to bikeshed but this is really a misnomer. it > doesn't check anything about locking. page_belongs_lruvec? Right. lruvec_holds_page_lru_lock is used to check whether the page belongs to the lruvec. page_belongs_lruvec obviously more clearer. I can rename it to page_belongs_lruvec the next version. > > > Signed-off-by: Muchun Song > > Acked-by: Johannes Weiner > > Acked-by: Michal Hocko Thanks. > > > --- > > include/linux/memcontrol.h | 31 +++++++------------------------ > > 1 file changed, 7 insertions(+), 24 deletions(-) > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > index 4f49865c9958..38b8d3fb24ff 100644 > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -755,22 +755,6 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page) > > return mem_cgroup_lruvec(memcg, pgdat); > > } > > > > -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; > > -} > > - > > struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); > > > > struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm); > > @@ -1229,14 +1213,6 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page) > > return &pgdat->__lruvec; > > } > > > > -static inline bool lruvec_holds_page_lru_lock(struct page *page, > > - struct lruvec *lruvec) > > -{ > > - pg_data_t *pgdat = page_pgdat(page); > > - > > - return lruvec == &pgdat->__lruvec; > > -} > > - > > static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page) > > { > > } > > @@ -1518,6 +1494,13 @@ static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, > > spin_unlock_irqrestore(&lruvec->lru_lock, flags); > > } > > > > +static inline bool lruvec_holds_page_lru_lock(struct page *page, > > + struct lruvec *lruvec) > > +{ > > + return lruvec_pgdat(lruvec) == page_pgdat(page) && > > + lruvec_memcg(lruvec) == page_memcg(page); > > +} > > + > > /* Don't lock again iff page's lruvec locked */ > > static inline struct lruvec *relock_page_lruvec_irq(struct page *page, > > struct lruvec *locked_lruvec) > > -- > > 2.11.0 > > -- > Michal Hocko > SUSE Labs