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Mon, 17 Aug 2026 16:05:37 +0000 X-Migadu-Flow: FLOW_OUT Date: Mon, 17 Aug 2026 09:05:35 -0700 From: Shakeel Butt To: Qi Zheng 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 Subject: Re: [PATCH v4 2/4] mm: memcontrol: make obj_cgroup_memcg() handle NULL objcg Message-ID: References: <09bcf74312246a6e4146be8a0cb9787f8beddb28.1786955972.git.zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09bcf74312246a6e4146be8a0cb9787f8beddb28.1786955972.git.zhengqi.arch@bytedance.com> X-Stat-Signature: 7afqe361k4tchzza7pc55doti64t8me5 X-Rspamd-Queue-Id: 73F3A40004 X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1786982738-801124 X-HE-Meta: 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 Cp1eEsAP LEp3nACwqBm1eRKeDR0jWB67X0tt0IPdZipnjPmKEQLyjhbJScgunwJSsY/DegmlSA7dhqDpW1GDxI+6IGroPmB/v6uwfjg7y6Znkr1LxwO2J3dstd2hNnFJ66n5W/yaAPUeUFkY/M+aC7o10Hx3PbHY4KNWxQ2qTWtqH0A+xNzUALVKjrxMOxUZadnC+PdwE/dFcRQ+5FZdrYDLYbbtz9NQHz5HQuCr4hE36zYmm30Ton6WRewYSpnQ6GppgGR5AxrF2TYHz/DYJSGmc6K4KIZyddFk2HkJL2e5zYSY2um6wZm8nKLioMPmOnzz8/b6bYorql8eHj2wq4nrujDtUtgSiaqmjl8gDnNz0uZqJU/i5LBfmKbrHqObo7cQ1AN6mHs4oSu4VdsSCt2mLUUZRGii97LVFe275tLZCZC9nDEyLFxY82ZHNd/irc+bEajNH8pHL Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 17, 2026 at 05:03:26PM +0800, Qi Zheng wrote: > From: Qi Zheng > > 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 Acked-by: Shakeel Butt