Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v3 3/7] mm/lru: replace pgdat lru_lock with lruvec lock
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Shakeel Butt <shakeelb@google.com>,
        Cgroups <cgroups@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Tejun Heo <tj@kernel.org>, Hugh Dickins <hughd@google.com>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Roman Gushchin <guro@fb.com>,
        Chris Down <chris@chrisdown.name>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vlastimil Babka <vbabka@suse.cz>, Qian Cai <cai@lca.pw>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        David Rientjes <rientjes@google.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        swkhack <swkhack@gmail.com>,
        "Potyra, Stefan" <Stefan.Potyra@elektrobit.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Colin Ian King <colin.king@canonical.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Peng Fan <peng.fan@nxp.com>,
        Nikolay Borisov <nborisov@suse.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Yafang Shao <laoar.shao@gmail.com>
References: <1573874106-23802-1-git-send-email-alex.shi@linux.alibaba.com>
 <1573874106-23802-4-git-send-email-alex.shi@linux.alibaba.com>
 <CALvZod7oUmUCk96ATrRwYvrROFNqL1gPGt7fy949M8TMwCQrWA@mail.gmail.com>
 <3f179d84-85e2-bace-2dbc-e77f73883c71@linux.alibaba.com>
 <20191118123138.GL20752@bombadil.infradead.org>
From:   Alex Shi <alex.shi@linux.alibaba.com>
Message-ID: <fc4716ae-a49e-68f0-98da-9318ff1f4138@linux.alibaba.com>
Date:   Tue, 19 Nov 2019 18:08:04 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:60.0)
 Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <20191118123138.GL20752@bombadil.infradead.org>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


在 2019/11/18 下午8:31, Matthew Wilcox 写道:
>> Thanks for comments, Shakeel.
>>
>> lruvec lifetime is same as memcg, which allocted in mem_cgroup_alloc()->alloc_mem_cgroup_per_node_info()
>> I have read Hugh's patchset, even not every lines. But what's point of you here?
> I believe Shakeel's point is that here:
> 
> struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
> {
> ...
>         memcg = page->mem_cgroup;
> 
> there is nothing pinning the memcg, and it could be freed before
> dereferencing memcg->nodeinfo in mem_cgroup_page_nodeinfo().

That's right! I will send the fix patches for review. 
Thanks a lot!