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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1761693850; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nlB9WJAF3YhOSJlj9moFGTAHILvUEPk36z3X23Y7y8Y=; b=bHOGkYGlqdYJuvtiAR/iv2AxNepGg0f5rNp8FrpwUHBrwiPDOVfZTtBT7gAhQftp/LaWRK tkTBQeL5oFLzo4UE11YBLEIi9jliZWh71t8hN9r23n5Bn+fHdTYokChGvi/23PJv6usiFX ESFA0MReO2ShiGO48zjD5eGfewGK3Fk= From: Roman Gushchin To: Song Liu Cc: Andrew Morton , linux-kernel@vger.kernel.org, Alexei Starovoitov , Suren Baghdasaryan , Michal Hocko , Shakeel Butt , Johannes Weiner , Andrii Nakryiko , JP Kobryn , linux-mm@kvack.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Kumar Kartikeya Dwivedi , Tejun Heo Subject: Re: [PATCH v2 06/23] mm: introduce BPF struct ops for OOM handling In-Reply-To: (Song Liu's message of "Tue, 28 Oct 2025 14:33:43 -0700") References: <20251027231727.472628-1-roman.gushchin@linux.dev> <20251027231727.472628-7-roman.gushchin@linux.dev> Date: Tue, 28 Oct 2025 16:24:04 -0700 Message-ID: <878qguobjf.fsf@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam01 X-Stat-Signature: z4g8z7jh8brbbihomqezp14qnbhbxgqo X-Rspam-User: X-Rspamd-Queue-Id: 3AE48180007 X-HE-Tag: 1761693852-188258 X-HE-Meta: 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 pHvCKiWo 46SVNkUVtN+cfkKnNIhKLYXbJdP1cWyilVhGFt63aRaL4kbrIyPAfkMyRPzyqdk2WZZT9a9dSznLSHSgWBLdesthhWfgCrrgTKfRWAI+Uw5VBap4uSQNUCGiWbl1RkiNyZFIvkeHzKr7gksilQyshz4flPoceB7igspYh1zo3+fBAgJwwQtzqGqSIVeoAbfAQcyYYd/FNEaSJpUcJpAOvvh1wCb3/N4vDpUeuOvMdKGSqHrQ= 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: List-Subscribe: List-Unsubscribe: Song Liu writes: > On Mon, Oct 27, 2025 at 4:18=E2=80=AFPM Roman Gushchin wrote: > [...] >> + >> +struct bpf_oom_ops { >> + /** >> + * @handle_out_of_memory: Out of memory bpf handler, called befo= re >> + * the in-kernel OOM killer. >> + * @ctx: Execution context >> + * @oc: OOM control structure >> + * >> + * Should return 1 if some memory was freed up, otherwise >> + * the in-kernel OOM killer is invoked. >> + */ >> + int (*handle_out_of_memory)(struct bpf_oom_ctx *ctx, struct oom_= control *oc); >> + >> + /** >> + * @handle_cgroup_offline: Cgroup offline callback >> + * @ctx: Execution context >> + * @cgroup_id: Id of deleted cgroup >> + * >> + * Called if the cgroup with the attached bpf_oom_ops is deleted. >> + */ >> + void (*handle_cgroup_offline)(struct bpf_oom_ctx *ctx, u64 cgrou= p_id); > > handle_out_of_memory() and handle_cgroup_offline() takes bpf_oom_ctx, > which is just cgroup_id for now. Shall we pass in struct mem_cgroup, which > should be easier to use? I want it to be easier to extend, this is why the structure. But I can pass a memcg pointer instead of cgroup_id, not a problem. Thanks! > > Thanks, > Song > >> + >> + /** >> + * @name: BPF OOM policy name >> + */ >> + char name[BPF_OOM_NAME_MAX_LEN]; >> +}; >> + >> +#ifdef CONFIG_BPF_SYSCALL >> +/** >> + * @bpf_handle_oom: handle out of memory condition using bpf >> + * @oc: OOM control structure >> + * >> + * Returns true if some memory was freed. >> + */ >> +bool bpf_handle_oom(struct oom_control *oc); >> +