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Thu, 18 Mar 2021 08:09:28 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:e46c]) by smtp.gmail.com with ESMTPSA id d14sm1561517qtj.92.2021.03.18.08.09.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 08:09:28 -0700 (PDT) Date: Thu, 18 Mar 2021 11:09:27 -0400 From: Johannes Weiner To: Muchun Song Cc: guro@fb.com, mhocko@kernel.org, akpm@linux-foundation.org, shakeelb@google.com, vdavydov.dev@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com Subject: Re: [PATCH v4 2/5] mm: memcontrol: directly access page->memcg_data in mm/page_alloc.c Message-ID: References: <20210318110658.60892-1-songmuchun@bytedance.com> <20210318110658.60892-3-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210318110658.60892-3-songmuchun@bytedance.com> X-Stat-Signature: yjecm8hg1ricae39w81rzw437k5bfurd X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C4429A0009E4 Received-SPF: none (cmpxchg.org>: No applicable sender policy available) receiver=imf24; identity=mailfrom; envelope-from=""; helo=mail-qt1-f180.google.com; client-ip=209.85.160.180 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616080169-249495 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 Thu, Mar 18, 2021 at 07:06:55PM +0800, Muchun Song wrote: > The page_memcg() is not suitable for use by page_expected_state() and > page_bad_reason(). Because it can BUG_ON() for the slab pages when > CONFIG_DEBUG_VM is enabled. As neither lru, nor kmem, nor slab page > should have anything left in there by the time the page is freed, what > we care about is whether the value of page->memcg_data is 0. So just > directly access page->memcg_data here. > > Signed-off-by: Muchun Song Acked-by: Johannes Weiner