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b=Q7M3muTAHD8kpFjXtUyq3zi080/5t6d9tcPFDyt+0GAnhnpvzR/rbfxPHP7UTk/66 4ANXrAxnDo+uy+SrKkekWheeh42CvDD5kydArSKGJPRjDhEGumGaz7J8XY3bUTlRZG iDYfV8fgOqejlgb7L3KGjBGrPuX/tQIcK02DLmrAaV0KFl+nqRs1LoopsbmWE3lDEx Il3VJbfTZ2jJAhIFBQTVurI7tVRifvulia3/xJTdPY1JerP2CjTygZCrlGLGuD2pb7 zEnXJP8qbxVeY7oVSLiaEs/CyKbUfDGEBEjgkT7vPUcrYyJuVT+cW8Jo63csmm8K96 +xTlky2qxWflA== Date: Thu, 4 Sep 2025 06:58:31 -1000 From: Tejun Heo To: Alexei Starovoitov Cc: Roman Gushchin , Martin KaFai Lau , Kumar Kartikeya Dwivedi , linux-mm , bpf , Suren Baghdasaryan , Johannes Weiner , Michal Hocko , David Rientjes , Matt Bobrowski , Song Liu , Alexei Starovoitov , Andrew Morton , LKML Subject: Re: [PATCH v1 01/14] mm: introduce bpf struct ops for OOM handling Message-ID: References: <1f2711b1-d809-4063-804b-7b2a3c8d933e@linux.dev> <87wm6rwd4d.fsf@linux.dev> <87iki0n4lm.fsf@linux.dev> <87qzwnxgfr.fsf@linux.dev> <87h5xi1e6p.fsf@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 4F85540007 X-Stat-Signature: hxrb46pdi5f5odh19ocupa4nhnqr4tkp X-Rspam-User: X-HE-Tag: 1757005114-893392 X-HE-Meta: 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 QBCaUQUr hXT6MwVhNt0fX/xplzWhn9f48Cn2L743Vs+YGQLnk8aYAxGyjATYRnuTTbptrsTv/00haiWDHB+kXjByxJ0qoNt344vIxTpTq9RPZahzl4NGQha9cb29MOwGHVDBW8YEfjqKtv15Py4Pe1XPb8s2h81IB4LN12eyXLJnOm22RkQ0ZcqvbDQbXztG3ZpPMMOtrcxiI/XZBKPH+v0dWw1rZpKOq5SJ/T/PmrQXwLKZXDnUJMvRmJ0jV1CGSFK4/gaRNezheNDQRv9yrke5toKxHrdMEsv9w6OoUMAMX 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: Hello, On Thu, Sep 04, 2025 at 09:26:45AM -0700, Alexei Starovoitov wrote: ... > > >> err = test_oom__attach_cgroup(skel, cgroup_fd); > > >> if (CHECK_FAIL(err)) > > >> goto cleanup; > > > > > > Yeah, that'd look better but are there practical differences? The only one I > > > can think of is fs based permission check but that can be done separately > > > too. > > > > The practical difference is that a single struct ops can be attached > > to multiple cgroups. > > +1 > Attaching the same scheduler to multiple cgroups also sounds useful. > I feel sched-ext should use cgroup_fd too and do scx_sub_enable() at > attach time instead of load time. > Then scx_sub_disable() can happen at link detach. > Looks more flexible from user pov. Nothing wrong with that but I'm not sure that'd have practical user-noticeable benefits for sched_ext. Also, would it affect how associated programs can identify which instance they belong to? At least from sched_ext POV, that's a lot more important than the ability to attach the same programs in multiple places. Thanks. -- tejun