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Wed, 29 Oct 2025 14:04:35 -0700 (PDT) MIME-Version: 1.0 References: <20251027231727.472628-1-roman.gushchin@linux.dev> <20251027231727.472628-3-roman.gushchin@linux.dev> In-Reply-To: <20251027231727.472628-3-roman.gushchin@linux.dev> From: Song Liu Date: Wed, 29 Oct 2025 14:04:24 -0700 X-Gmail-Original-Message-ID: X-Gm-Features: AWmQ_bmwLAYqjY6FqVrt95b3pom6p-BA2r_4lSQbeFy3VWdjR4QavcuPY05pP8A Message-ID: Subject: Re: [PATCH v2 02/23] bpf: initial support for attaching struct ops to cgroups To: Roman Gushchin 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 , Song Liu , Kumar Kartikeya Dwivedi , Tejun Heo Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam01 X-Stat-Signature: oipsetjw8pxjngk9rsf1g5w8zg56q6a8 X-Rspam-User: X-Rspamd-Queue-Id: 98AF6A0019 X-HE-Tag: 1761771877-949756 X-HE-Meta: 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 for8ZI7V 0mCtJId+1A3KRvGD/qroa1HggPPnIhuKUJ1EZ/l77HisXG93YvyI3zp6MseSOanGLthdBI/glDD8QLi++OG7hcoe95TORNkBzElrVYOsw9aHh8DJpCoC4OaQQW6scuR+UOvETDZaVi+zZqNgcrzq9xHLyy+zKjIG/xoKGurXvRw+1uq/ezMv9JGZV1dRKzWrZvSvL3aM7xRk5gyAJWDC3jga434eddA2FzExALlDkggBMnT+MCR62ADlbnn7iw9lbY6bF0fzsVjhZwDekJRkxYJKdWF5MTafRmi0qRZsqlXzLArEEhhbz9vecEA== 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: On Mon, Oct 27, 2025 at 4:17=E2=80=AFPM Roman Gushchin wrote: > > When a struct ops is being attached and a bpf link is created, > allow to pass a cgroup fd using bpf attr, so that struct ops > can be attached to a cgroup instead of globally. > > Attached struct ops doesn't hold a reference to the cgroup, > only preserves cgroup id. With the current model, when a cgroup is freed, the bpf link still holds a reference to the struct_ops. Can we make the cgroup to hold a reference to the struct_ops, so that the struct_ops is freed automatically when the cgroup is freed? I think the downside is that we will need an API to remove/change per cgroup OOM handler. Thanks, Song