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Howlett" , Suren Baghdasaryan , Alexei Starovoitov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, bpf@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH RFC v2 06/20] slab: make percpu sheaves compatible with kmalloc_nolock()/kfree_nolock() Message-ID: <20260113183604.ykHFYvV2@linutronix.de> References: <20260112-sheaves-for-all-v2-0-98225cfb50cf@suse.cz> <20260112-sheaves-for-all-v2-6-98225cfb50cf@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260112-sheaves-for-all-v2-6-98225cfb50cf@suse.cz> X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7C64640007 X-Stat-Signature: 99736i8insokx3s1jr6f7mu7ffsnfgrz X-HE-Tag: 1768329367-949212 X-HE-Meta: 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 Dj0IkAKY BQwuNI7NiDYcvEEa5tgDF3i4kAW3ICRDxVJJuFhiS8zUNd5SYk9AQnD+iwIXw6H9stz/bqodszmbKr35b0NsAr93DuGMyQpLhe3l87HrdfiQBE2WO8dNJLsWR7dXZpM7kH6XFICxYcnToG+SI3MTegHx1cWPmNBrm8nZ3CoTTc6PE9MaZfScVA4AHAGDgFhT90PUV/bAj7Q/nPsaO6yX1fi+pKlEOTg3aK+q40ijX5xVj7ywsQee2+8vJ/4HndNpMNvPVezowTrXNoUqpqcGsjrxY0cUfg4aeLibY 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 2026-01-12 16:17:00 [+0100], Vlastimil Babka wrote: > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -5727,6 +5742,12 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node) > */ > return NULL; > > + ret = alloc_from_pcs(s, alloc_gfp, node); > + if (ret) > + goto success; I'm sorry if I am slow but this actually should actually allow kmalloc_nolock() allocations on PREEMPT_RT from atomic context. I am mentioning this because of the patch which removes the nmi+hardirq condtion (https://lore.kernel.org/all/20260113150639.48407-1-swarajgaikwad1925@gmail.com) > + > + ret = ERR_PTR(-EBUSY); > + > /* > * Do not call slab_alloc_node(), since trylock mode isn't > * compatible with slab_pre_alloc_hook/should_failslab and Sebastian