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AJvYcCXdqEQ9BOv+eazAbcrFMpa+U954GqHJVFDGhP7FJg1AiHz2CWGlBctRqqxVhuYBlzpr/0s=@vger.kernel.org X-Gm-Message-State: AOJu0YxrBCYYc9sjL+jjSKgVGPWImYQNXM5wI5JZA206dRpp7oSlKiQ2 HFffBqa9RgDaa0yuAmEh2m9YW+459hNJA52jhC6n524jHdR0KQ4P3p2NrkEcNT57yetJRUOV5bf 76c7QlW84PxpFXPqIslC+XZVb9S03mq0= X-Gm-Gg: AZuq6aKqsve/cKAKV1Y4lgjTDD7Tvv3e1dnNtUyMVcJsgqXsfdTsTH/qVAmPppovoN5 TS5SdjmoF3bh0tr5HQgqGGNmFtd4SSjyp2NgTU1VXq7TAtj5PYoVHDq0hPOWCKe68f90Px3ciVE E/MMfAiP/u/UNOzjz3dW0g1/47ujkzeHy8ztJEZkJlU3RILl+++u53WWsm7DlXyVOAP+9Q0wCO+ AZUihgMptTFie4Pf5w7sMzOgdHG+FUCQdoliYUiT3/K96n6dDVRMBscvm0rRsPrcTMJGdC64OlN s/vapzXJRkyMeJcGXxtHgRL0CRgLJVaZlRnrmtAK8s9b/tIeiXzO3BTaPEzmoIFF2XZt784qjCZ 7D6XDiNQA5Z3VAg== X-Received: by 2002:a05:6000:2285:b0:435:a0ca:bdce with SMTP id ffacd0b85a97d-436293b6d91mr19720428f8f.63.1770662709254; Mon, 09 Feb 2026 10:45:09 -0800 (PST) Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260206093410.160622-1-harry.yoo@oracle.com> <20260206093410.160622-5-harry.yoo@oracle.com> In-Reply-To: From: Alexei Starovoitov Date: Mon, 9 Feb 2026 10:44:57 -0800 X-Gm-Features: AZwV_QhH5LLE8iIvDB7Twan7nOo9YGILnwQ7hrloMARMGnUSRQtlNRKOCRmQfK8 Message-ID: Subject: Re: [RFC PATCH 4/7] mm/slab: free a bit in enum objexts_flags To: Vlastimil Babka Cc: Harry Yoo , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Johannes Weiner , Shakeel Butt , Michal Hocko , Hao Li , Alexei Starovoitov , Puranjay Mohan , Andrii Nakryiko , Amery Hung , Catalin Marinas , "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Dave Chinner , Qi Zheng , Muchun Song , rcu@vger.kernel.org, linux-mm , bpf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, Feb 9, 2026 at 1:38=E2=80=AFAM Vlastimil Babka wro= te: > > On 2/6/26 21:09, Alexei Starovoitov wrote: > > On Fri, Feb 6, 2026 at 1:35=E2=80=AFAM Harry Yoo = wrote: > >> > >> Since kfree() now supports freeing objects allocated with > >> kmalloc_nolock(), free one bit in enum object_flags. > >> > >> Signed-off-by: Harry Yoo > > > > For patches 3 and 4: > > > > Acked-by: Alexei Starovoitov > > > > I think patches 3 and 4 are ready. > > Would be great to land them for this merge window > > (if Vlastimil agrees). > > We should have an ack from Catalin for kmemleak. Also better take them ou= t > of the RFC and send as 2 non-rfc patches first, with cc list reduced > accordingly etc. > > Then I can put them to -next and try sending second merge window PR next > week. Can you also point to any bug reports that would be fixed? (that yo= u > had to work around or delay merging or something) that would help the > argument to not wait a cycle. Here is one example: https://lore.kernel.org/all/20251114201329.3275875-1-ameryhung@gmail.com/ " RFC v1 tried to switch to kmalloc_nolock() unconditionally. However, as there is substantial performance loss in socket local storage due to 1) defer_free() in kfree_nolock() and 2) no kfree_rcu() batching, replacing kzalloc() is postponed until necessary improvements in mm land. " This patch addresses both 1 and 2. The freeing is done in a good context. The only reason we use kfree_nolock() and suffer from defer_free and lack of batching is due to kmalloc_nolock()->kfree_nolock() matching requirement. So this small patch is a big deal. We will be able to use kmalloc_nolock() -> kfree_rcu().