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Sun, 14 Sep 2025 10:23:07 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 9737014456621 X-SMAIL-UIID: 2DC8645A57844B7B918BD48ADEA49B19-20250914-102307-1 From: Hillf Danton To: Vlastimil Babka Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 01/14] slab: add opt-in caching layer of percpu sheaves Date: Sun, 14 Sep 2025 10:22:57 +0800 Message-ID: <20250914022258.7062-1-hdanton@sina.com> In-Reply-To: <20250723-slub-percpu-caches-v5-1-b792cd830f5d@suse.cz> References: <20250723-slub-percpu-caches-v5-0-b792cd830f5d@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: A8C414000B X-Rspamd-Server: rspam05 X-Stat-Signature: mfmu6r13fs4jocr8g98g55rnggdf8tfi X-Rspam-User: X-HE-Tag: 1757816592-4637 X-HE-Meta: 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 i+1tnh0e Q4iAh 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 Wed, 23 Jul 2025 15:34:34 +0200 Vlastimil Babka wrote: > + > +/* > + * Caller needs to make sure migration is disabled in order to fully flush > + * single cpu's sheaves > + * This misguides, see below for a workqueue case. > + * must not be called from an irq > + * > + * flushing operations are rare so let's keep it simple and flush to slabs > + * directly, skipping the barn > + */ > +static void pcs_flush_all(struct kmem_cache *s) > +{ > + struct slub_percpu_sheaves *pcs; > + struct slab_sheaf *spare; > + > + local_lock(&s->cpu_sheaves->lock); > + pcs = this_cpu_ptr(s->cpu_sheaves); > + > + spare = pcs->spare; > + pcs->spare = NULL; > + > + local_unlock(&s->cpu_sheaves->lock); > + > + if (spare) { > + sheaf_flush_unused(s, spare); > + free_empty_sheaf(s, spare); > + } > + > + sheaf_flush_main(s); > +} > + > @@ -3326,30 +3755,18 @@ struct slub_flush_work { > static void flush_cpu_slab(struct work_struct *w) > { > struct kmem_cache *s; > - struct kmem_cache_cpu *c; > struct slub_flush_work *sfw; > > sfw = container_of(w, struct slub_flush_work, work); > > s = sfw->s; > - c = this_cpu_ptr(s->cpu_slab); > > - if (c->slab) > - flush_slab(s, c); > + if (s->cpu_sheaves) > + pcs_flush_all(s); > Migration is not disabled. > - put_partials(s); > + flush_this_cpu_slab(s); > }