From: Shakeel Butt <shakeel.butt@linux.dev>
To: Qi Zheng <qi.zheng@linux.dev>
Cc: hughd@google.com, baolin.wang@linux.alibaba.com,
usama.arif@linux.dev, brauner@kernel.org,
akpm@linux-foundation.org, david@kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Qi Zheng <zhengqi.arch@bytedance.com>
Subject: Re: [PATCH v4 2/4] mm: memcontrol: make obj_cgroup_memcg() handle NULL objcg
Date: Mon, 17 Aug 2026 09:05:35 -0700 [thread overview]
Message-ID: <aoMxN97qg8uzk04R@linux.dev> (raw)
In-Reply-To: <09bcf74312246a6e4146be8a0cb9787f8beddb28.1786955972.git.zhengqi.arch@bytedance.com>
On Mon, Aug 17, 2026 at 05:03:26PM +0800, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@bytedance.com>
>
> obj_cgroup_memcg() currently requires a non-NULL objcg, so callers that
> may hold a NULL objcg must guard the call with an explicit NULL check.
> This pattern is duplicated in folio_memcg(), folio_memcg_check(),
> mm/page_owner.c, and mm/zswap.c.
>
> Teach obj_cgroup_memcg() to accept NULL and return NULL in that case, then
> remove the redundant NULL checks at the call sites. Also remove the
> mem_cgroup_from_entry() wrapper in zswap, which existed solely to provide
> this NULL-safe behaviour, and replace its two callers with direct
> obj_cgroup_memcg() calls.
>
> No functional change intended.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
next prev parent reply other threads:[~2026-08-17 16:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-17 9:03 [PATCH v4 0/4] make unused huge shrinker memcg aware Qi Zheng
2026-08-17 9:03 ` [PATCH v4 1/4] fs: fix missed removal of super_fs_objects_eligible() Qi Zheng
2026-08-17 9:03 ` [PATCH v4 2/4] mm: memcontrol: make obj_cgroup_memcg() handle NULL objcg Qi Zheng
2026-08-17 11:29 ` Qi Zheng
2026-08-17 16:05 ` Shakeel Butt [this message]
2026-08-17 9:03 ` [PATCH v4 3/4] mm: shmem: move unused huge shrinklist queuing past the truncation check Qi Zheng
2026-08-17 9:03 ` [PATCH v4 4/4] mm: shmem: make unused huge shrinker memcg aware Qi Zheng
2026-08-18 3:54 ` Baolin Wang
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