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b=40ObUHLUWyTtsyo7VM6q8v3Scind4/Ubjn28AvhTB1BWxzficxhr/BOj1Ak9F9rSwSj6UN +Dtsqe0OY/rifSBQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 3DA491377F; Wed, 26 Feb 2025 10:58:10 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id HQrvDcLzvmdaeQAAD6G6ig (envelope-from ); Wed, 26 Feb 2025 10:58:10 +0000 Message-ID: <8d7aabb2-2836-4c09-9fc7-8bde271e7f23@suse.cz> Date: Wed, 26 Feb 2025 11:59:53 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 6/7] mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy() To: Uladzislau Rezki , Keith Busch Cc: "Paul E. McKenney" , Joel Fernandes , Josh Triplett , Boqun Feng , Christoph Lameter , David Rientjes , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Julia Lawall , Jakub Kicinski , "Jason A. Donenfeld" , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, Jann Horn , Mateusz Guzik , linux-nvme@lists.infradead.org, leitao@debian.org References: <20240807-b4-slab-kfree_rcu-destroy-v2-0-ea79102f428c@suse.cz> <20240807-b4-slab-kfree_rcu-destroy-v2-6-ea79102f428c@suse.cz> <2811463a-751f-4443-9125-02628dc315d9@suse.cz> From: Vlastimil Babka Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 68A6221184 X-Spam-Score: -3.01 X-Rspamd-Action: no action X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; ARC_NA(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; RCPT_COUNT_TWELVE(0.00)[29]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; FREEMAIL_CC(0.00)[kernel.org,joelfernandes.org,joshtriplett.org,gmail.com,linux.com,google.com,goodmis.org,efficios.com,inria.fr,zx2c4.com,linux-foundation.org,linux.dev,kvack.org,vger.kernel.org,googlegroups.com,lists.infradead.org,debian.org]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; DKIM_TRACE(0.00)[suse.cz:+]; R_RATELIMIT(0.00)[to_ip_from(RLctujmen6hjyrx8fu4drawbuj)]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo,suse.cz:mid,suse.cz:dkim] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO X-Spam-Level: On 2/25/25 7:21 PM, Uladzislau Rezki wrote: >> > WQ_MEM_RECLAIM-patch fixes this for me: Sounds good, can you send a formal patch then? Some nits below: > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 4030907b6b7d..1b5ed5512782 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1304,6 +1304,8 @@ module_param(rcu_min_cached_objs, int, 0444); > static int rcu_delay_page_cache_fill_msec = 5000; > module_param(rcu_delay_page_cache_fill_msec, int, 0444); > > +static struct workqueue_struct *rcu_reclaim_wq; > + > /* Maximum number of jiffies to wait before draining a batch. */ > #define KFREE_DRAIN_JIFFIES (5 * HZ) > #define KFREE_N_BATCHES 2 > @@ -1632,10 +1634,10 @@ __schedule_delayed_monitor_work(struct kfree_rcu_cpu *krcp) > if (delayed_work_pending(&krcp->monitor_work)) { > delay_left = krcp->monitor_work.timer.expires - jiffies; > if (delay < delay_left) > - mod_delayed_work(system_unbound_wq, &krcp->monitor_work, delay); > + mod_delayed_work(rcu_reclaim_wq, &krcp->monitor_work, delay); > return; > } > - queue_delayed_work(system_unbound_wq, &krcp->monitor_work, delay); > + queue_delayed_work(rcu_reclaim_wq, &krcp->monitor_work, delay); > } > > static void > @@ -1733,7 +1735,7 @@ kvfree_rcu_queue_batch(struct kfree_rcu_cpu *krcp) > // "free channels", the batch can handle. Break > // the loop since it is done with this CPU thus > // queuing an RCU work is _always_ success here. > - queued = queue_rcu_work(system_unbound_wq, &krwp->rcu_work); > + queued = queue_rcu_work(rcu_reclaim_wq, &krwp->rcu_work); > WARN_ON_ONCE(!queued); > break; > } > @@ -1883,7 +1885,7 @@ run_page_cache_worker(struct kfree_rcu_cpu *krcp) > if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING && > !atomic_xchg(&krcp->work_in_progress, 1)) { > if (atomic_read(&krcp->backoff_page_cache_fill)) { > - queue_delayed_work(system_unbound_wq, > + queue_delayed_work(rcu_reclaim_wq, > &krcp->page_cache_work, > msecs_to_jiffies(rcu_delay_page_cache_fill_msec)); > } else { > @@ -2120,6 +2122,10 @@ void __init kvfree_rcu_init(void) > int i, j; > struct shrinker *kfree_rcu_shrinker; > > + rcu_reclaim_wq = alloc_workqueue("rcu_reclaim", Should we name it "kvfree_rcu_reclaim"? rcu_reclaim sounds too generic as if it's part of rcu itself? > + WQ_UNBOUND | WQ_MEM_RECLAIM, 0); Do we want WQ_SYSFS? Or maybe only when someone asks, with a use case? Thanks, Vlastimil > + WARN_ON(!rcu_reclaim_wq); > + > /* Clamp it to [0:100] seconds interval. */ > if (rcu_delay_page_cache_fill_msec < 0 || > rcu_delay_page_cache_fill_msec > 100 * MSEC_PER_SEC) { > > > it passes: > > > [ 15.972416] KTAP version 1 > [ 15.972421] 1..1 > [ 15.973467] KTAP version 1 > [ 15.973470] # Subtest: slub_test > [ 15.973472] # module: slub_kunit > [ 15.973474] 1..10 > [ 15.974483] ok 1 test_clobber_zone > [ 15.974927] ok 2 test_next_pointer > [ 15.975308] ok 3 test_first_word > [ 15.975672] ok 4 test_clobber_50th_byte > [ 15.976035] ok 5 test_clobber_redzone_free > [ 15.976128] stackdepot: allocating hash table of 1048576 entries via kvcalloc > [ 15.979505] ok 6 test_kmalloc_redzone_access > [ 16.014408] ok 7 test_kfree_rcu > [ 17.726602] ok 8 test_kfree_rcu_wq_destroy > [ 17.750323] ok 9 test_leak_destroy > [ 17.750883] ok 10 test_krealloc_redzone_zeroing > [ 17.750887] # slub_test: pass:10 fail:0 skip:0 total:10 > [ 17.750890] # Totals: pass:10 fail:0 skip:0 total:10 > [ 17.750891] ok 1 slub_test > > > -- > Uladzislau Rezki