From: Bingfang Guo <bfguo@icloud.com>
To: Muchun Song <muchun.song@linux.dev>
Cc: bingfangguo@tencent.com, Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Chinner <david@fromorbit.com>, Qi Zheng <qi.zheng@linux.dev>,
Kairui Song <kasong@tencent.com>, Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v2 6/6] mm/memcg: filter out reparented memcgs got from memcgid
Date: Sun, 6 Sep 2026 03:45:15 +0800 [thread overview]
Message-ID: <apxxS-R-GgXpe-Pt@BINGFANGGUO-MC0> (raw)
In-Reply-To: <3F681C23-8462-4BA3-B3C6-B7A45A9341DE@linux.dev>
On Sat, Sep 05, 2026 at 08:18:03PM +0800, Muchun Song wrote:
>
>
> > On Sep 1, 2026, at 16:58, Bingfang Guo via B4 Relay <devnull+bingfangguo.tencent.com@kernel.org> wrote:
> >
> > From: Bingfang Guo <bingfangguo@tencent.com>
> >
> > mem_cgroup_from_private_id() looks up the objcg that owns the id and
> > returns the objcg's current memcg. After reparenting, that memcg can
> > differ from the one the id originally belonged to.
> >
> > Callers such as the list lru and workingset refault code expect to get
> > back exactly the memcg referred to by the memcgid, so check that the
> > returned memcg still owns the id and return NULL otherwise. In this
> > case, make list_lru just skip and workingset tests use the root (as the
> > comments said in workingset.c:460).
> >
> > Signed-off-by: Bingfang Guo <bingfangguo@tencent.com>
>
> We should move this patch earlier to avoid introducing the problem first
> and then fixing it later.
OK. I will keep that in mind.
Regards,
Bingfang
>
> Muchun,
> Thanks.
>
prev parent reply other threads:[~2026-09-05 19:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-01 8:57 [PATCH RFC v2 0/6] mm/memcg: move memcgid refcount to objcg to unpin dying memcgs Bingfang Guo via B4 Relay
2026-09-01 8:58 ` [PATCH RFC v2 1/6] mm/memcg: add a helper to kill the memcgid on offlining Bingfang Guo via B4 Relay
2026-09-01 8:58 ` [PATCH RFC v2 2/6] mm/memcg: get memcgid reference only after swap charging success Bingfang Guo via B4 Relay
2026-09-01 16:15 ` Bingfang Guo
2026-09-05 7:12 ` Muchun Song
2026-09-05 19:35 ` Bingfang Guo
2026-09-01 8:58 ` [PATCH RFC v2 3/6] mm/memcg: pass the id itself instead of memcg for putting ID Bingfang Guo via B4 Relay
2026-09-05 10:01 ` Muchun Song
2026-09-05 19:48 ` Bingfang Guo
2026-09-01 8:58 ` [PATCH RFC v2 4/6] mm/memcg: return the memcg when putting memcgid Bingfang Guo via B4 Relay
2026-09-01 15:58 ` Bingfang Guo
2026-09-05 7:28 ` Muchun Song
2026-09-05 19:36 ` Bingfang Guo
2026-09-01 8:58 ` [PATCH RFC v2 5/6] mm/memcg: move memcg private ID refcount to objcg Bingfang Guo via B4 Relay
2026-09-05 8:46 ` Muchun Song
2026-09-05 19:44 ` Bingfang Guo
2026-09-01 8:58 ` [PATCH RFC v2 6/6] mm/memcg: filter out reparented memcgs got from memcgid Bingfang Guo via B4 Relay
2026-09-02 3:53 ` Bingfang Guo
2026-09-05 12:18 ` Muchun Song
2026-09-05 19:45 ` Bingfang Guo [this message]
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