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[2a02:3100:a128:aa01:297a:7094:853e:a20c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a18bf2caf4sm41656205e9.10.2026.10.09.00.07.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2026 00:07:42 -0700 (PDT) Date: Fri, 9 Oct 2026 09:07:41 +0200 From: Karl Mehltretter To: Harry Yoo Cc: Vlastimil Babka , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Muchun Song , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , Alexei Starovoitov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH 1/2] mm/slub: preserve no-lock freeing after memcg charge failure Message-ID: References: <20261001044056.75079-1-kmehltretter@gmail.com> <20261001044056.75079-2-kmehltretter@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: C826B40008 X-Stat-Signature: eumpga8a1xwffk6we1qfo6bafaqmzxua X-HE-Tag: 1791529664-394981 X-HE-Meta: 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 2VudQgux 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Oct 07, 2026 at 07:40:17PM +0100, Harry Yoo wrote: > > > > Use kfree_nolock() when the allocation flags disallow spinning. This > > keeps the SLUB object rollback on the no-lock free path. The failed > > allocation continues to return NULL. > > When this happens, the object is not charged by memcg. > > The kernel should not invoke memcg_slab_free_hook() (called by > kfree_nolock()) for a slab object that is not charged by memcg. > Agreed. I'll avoid the memcg free hook on charge abort. One question: kfree_nolock() currently skips init_on_free, while the existing charge-abort path honors it. Was that intentional? I couldn't find it discussed in the introduction threads. If kfree_nolock() should honor init_on_free, I'll include that fix as the first patch in the revised series. The charge-abort fix will then reuse the shared initialization helper. Karl