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[90.233.216.238]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-52ca2887d56sm1239456e87.263.2024.06.17.06.50.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Jun 2024 06:50:59 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 17 Jun 2024 15:50:56 +0200 To: "Jason A. Donenfeld" Cc: Uladzislau Rezki , "Paul E. McKenney" , Vlastimil Babka , Jakub Kicinski , Julia Lawall , linux-block@vger.kernel.org, kernel-janitors@vger.kernel.org, bridge@lists.linux.dev, linux-trace-kernel@vger.kernel.org, Mathieu Desnoyers , kvm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "Naveen N. Rao" , Christophe Leroy , Nicholas Piggin , netdev@vger.kernel.org, wireguard@lists.zx2c4.com, linux-kernel@vger.kernel.org, ecryptfs@vger.kernel.org, Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, linux-can@vger.kernel.org, Lai Jiangshan , netfilter-devel@vger.kernel.org, coreteam@netfilter.org 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> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jun 14, 2024 at 09:33:45PM +0200, Jason A. Donenfeld wrote: > 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()`. > I do not find pooling as bad way we can go with. But your proposal sounds reasonable to me also. We can combine both "prototypes" to one and offer. Can you post a prototype here? Thanks! -- Uladzislau Rezki