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Wed, 14 Apr 2021 10:49:58 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:f8bd]) by smtp.gmail.com with ESMTPSA id h23sm59950qtr.21.2021.04.14.10.49.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Apr 2021 10:49:58 -0700 (PDT) Date: Wed, 14 Apr 2021 13:49:56 -0400 From: Johannes Weiner To: Muchun Song Cc: Michal Hocko , guro@fb.com, 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 Subject: Re: [External] Re: [PATCH 4/7] mm: memcontrol: simplify lruvec_holds_page_lru_lock Message-ID: References: <20210413065153.63431-1-songmuchun@bytedance.com> <20210413065153.63431-5-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 175DA40002DE X-Stat-Signature: w13oxumhxnyk6q1qxt1zu156doh68jnc Received-SPF: none (cmpxchg.org>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=mail-qk1-f172.google.com; client-ip=209.85.222.172 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618422596-987847 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 Wed, Apr 14, 2021 at 06:00:42PM +0800, Muchun Song wrote: > 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. This sounds strange to me, I think 'belongs' needs a 'to' to be correct, so page_belongs_to_lruvec(). Still kind of a mouthful. page_matches_lruvec()? page_from_lruvec()?