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Donenfeld" To: Uladzislau Rezki Subject: Re: [PATCH 00/14] replace call_rcu by kfree_rcu for simple kmem_cache_free callback Message-ID: References: <80e03b02-7e24-4342-af0b-ba5117b19828@paulmck-laptop> <7efde25f-6af5-4a67-abea-b26732a8aca1@paulmck-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, Neil Brown , kernel-janitors@vger.kernel.org, Olga Kornievskaia , Dai Ngo , Christophe Leroy , coreteam@netfilter.org, "Naveen N. Rao" , Jakub Kicinski , linux-trace-kernel@vger.kernel.org, "Paul E. McKenney" , bridge@lists.linux.dev, ecryptfs@vger.kernel.org, Nicholas Piggin , linux-can@vger.kernel.org, linux-block@vger.kernel.org, Mathieu Desnoyers , Vlastimil Babka , Tom Talpey , linux-nfs@vger.kernel.org, netdev@vger.kernel.org, Lai Jiangshan , linux-kernel@vger.kernel.org, Julia Lawall , netfilter-devel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, wireguard@lists.zx2c4.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Jun 14, 2024 at 02:35:33PM +0200, Uladzislau Rezki wrote: > + /* Should a destroy process be deferred? */ > + if (s->flags & SLAB_DEFER_DESTROY) { > + list_move_tail(&s->list, &slab_caches_defer_destroy); > + schedule_delayed_work(&slab_caches_defer_destroy_work, HZ); > + goto out_unlock; > + } Wouldn't it be smoother to have the actual kmem_cache_free() function check to see if it's been marked for destruction and the refcount is zero, rather than polling every one second? I mentioned this approach in: https://lore.kernel.org/all/Zmo9-YGraiCj5-MI@zx2c4.com/ - I wonder if the right fix to this would be adding a `should_destroy` boolean to kmem_cache, which kmem_cache_destroy() sets to true. And then right after it checks `if (number_of_allocations == 0) actually_destroy()`, and likewise on each kmem_cache_free(), it could check `if (should_destroy && number_of_allocations == 0) actually_destroy()`. Jason