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Mon, 09 Feb 2026 10:45:09 -0800 (PST) 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 X-Rspam-User: X-Rspamd-Queue-Id: 22CA9120002 X-Rspamd-Server: rspam07 X-Stat-Signature: i878aqzx1pdn93itfuef37ebzfchny4t X-HE-Tag: 1770662710-829659 X-HE-Meta: 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 JGGJDkWf 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 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, 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().