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[209.85.220.65]) by mx.google.com with SMTPS id g95sor23379plb.5.2019.04.17.14.54.56 for (Google Transport Security); Wed, 17 Apr 2019 14:54:56 -0700 (PDT) Received-SPF: pass (google.com: domain of guroan@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=bkJtX8C+; spf=pass (google.com: domain of guroan@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=guroan@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=MtkthRXb9xr3Z6+sHE+ddzmShZROkNDy015XAdhrxgc=; b=bkJtX8C+3fj0Tjhyg4vCVv/IFmBzbGBkiaDAvFLmDb8Lq2CSpvTCu0DpsxNBzVRZE6 /KavKK6sZJp6q1on9j4P5GAND/bIlyXqkI64KWpz4q5A+ph+Wga2tCFOg5zBESw4qB6F 0a8qx/VE5UXWEj/OfguZ1W6Acn8pwoIJDzZu71ecJg94TK4ni4QRK9oElJ9DPSm60c+g K0zyATOpmJW3pcoANLB3OTOt8dtYU0H7WgFn7PoNVvhHacgEQcsm7GTnMLHoclASVfe4 LiW1YvyENbVaOxl0Qz3UxRV4EsfpG6OXUukFSX+jgB8C/tTLlnztGVBcSkJ+IPrW2RX7 G1Xg== X-Google-Smtp-Source: APXvYqwg/PODrPNFlRfYDoK4DEAkGsveLbL3EEOb4pDRkT0d8MTv1g9F41Dfa37BfIh/CXJNuXPr9w== X-Received: by 2002:a17:902:e382:: with SMTP id ch2mr89133541plb.94.1555538096288; Wed, 17 Apr 2019 14:54:56 -0700 (PDT) Received: from tower.thefacebook.com ([2620:10d:c090:200::5597]) by smtp.gmail.com with ESMTPSA id x6sm209024pfb.171.2019.04.17.14.54.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 17 Apr 2019 14:54:55 -0700 (PDT) From: Roman Gushchin X-Google-Original-From: Roman Gushchin To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Johannes Weiner , Michal Hocko , Rik van Riel , david@fromorbit.com, Christoph Lameter , Pekka Enberg , Vladimir Davydov , cgroups@vger.kernel.org, Roman Gushchin Subject: [PATCH 2/5] mm: generalize postponed non-root kmem_cache deactivation Date: Wed, 17 Apr 2019 14:54:31 -0700 Message-Id: <20190417215434.25897-3-guro@fb.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190417215434.25897-1-guro@fb.com> References: <20190417215434.25897-1-guro@fb.com> MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP Currently SLUB uses a work scheduled after an RCU grace period to deactivate a non-root kmem_cache. This mechanism can be reused for kmem_caches reparenting, but requires some generalization. Let's decouple all infrastructure (rcu callback, work callback) from the SLUB-specific code, so it can be used with SLAB as well. Also, let's rename some functions to make the code look simpler. All SLAB/SLUB-specific functions start with "__". Remove "deact_" prefix from the corresponding struct fields. Here is the graph of a new calling scheme: kmemcg_cache_deactivate() __kmemcg_cache_deactivate() SLAB/SLUB-specific kmemcg_schedule_work_after_rcu() rcu kmemcg_after_rcu_workfn() work kmemcg_cache_deactivate_after_rcu() __kmemcg_cache_deactivate_after_rcu() SLAB/SLUB-specific instead of: __kmemcg_cache_deactivate() SLAB/SLUB-specific slab_deactivate_memcg_cache_rcu_sched() SLUB-only kmemcg_deactivate_rcufn SLUB-only, rcu kmemcg_deactivate_workfn SLUB-only, work kmemcg_cache_deact_after_rcu() SLUB-only Signed-off-by: Roman Gushchin --- include/linux/slab.h | 6 ++--- mm/slab.c | 4 +++ mm/slab.h | 3 ++- mm/slab_common.c | 62 ++++++++++++++++++++------------------------ mm/slub.c | 8 +----- 5 files changed, 38 insertions(+), 45 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 9449b19c5f10..47923c173f30 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -642,10 +642,10 @@ struct memcg_cache_params { struct list_head children_node; struct list_head kmem_caches_node; - void (*deact_fn)(struct kmem_cache *); + void (*work_fn)(struct kmem_cache *); union { - struct rcu_head deact_rcu_head; - struct work_struct deact_work; + struct rcu_head rcu_head; + struct work_struct work; }; }; }; diff --git a/mm/slab.c b/mm/slab.c index 57a332f524cf..14466a73d057 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2317,6 +2317,10 @@ void __kmemcg_cache_deactivate(struct kmem_cache *cachep) { __kmem_cache_shrink(cachep); } + +void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s) +{ +} #endif int __kmem_cache_shutdown(struct kmem_cache *cachep) diff --git a/mm/slab.h b/mm/slab.h index 6a562ca72bca..4a261c97c138 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -172,6 +172,7 @@ int __kmem_cache_shutdown(struct kmem_cache *); void __kmem_cache_release(struct kmem_cache *); int __kmem_cache_shrink(struct kmem_cache *); void __kmemcg_cache_deactivate(struct kmem_cache *s); +void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s); void slab_kmem_cache_release(struct kmem_cache *); struct seq_file; @@ -291,7 +292,7 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order, extern void slab_init_memcg_params(struct kmem_cache *); extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg); extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, - void (*deact_fn)(struct kmem_cache *)); + void (*work_fn)(struct kmem_cache *)); #else /* CONFIG_MEMCG_KMEM */ diff --git a/mm/slab_common.c b/mm/slab_common.c index 6e00bdf8618d..4e5b4292a763 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -691,17 +691,18 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg, put_online_cpus(); } -static void kmemcg_deactivate_workfn(struct work_struct *work) +static void kmemcg_after_rcu_workfn(struct work_struct *work) { struct kmem_cache *s = container_of(work, struct kmem_cache, - memcg_params.deact_work); + memcg_params.work); get_online_cpus(); get_online_mems(); mutex_lock(&slab_mutex); - s->memcg_params.deact_fn(s); + s->memcg_params.work_fn(s); + s->memcg_params.work_fn = NULL; mutex_unlock(&slab_mutex); @@ -712,37 +713,28 @@ static void kmemcg_deactivate_workfn(struct work_struct *work) css_put(&s->memcg_params.memcg->css); } -static void kmemcg_deactivate_rcufn(struct rcu_head *head) +/* + * We need to grab blocking locks. Bounce to ->work. The + * work item shares the space with the RCU head and can't be + * initialized eariler. +*/ +static void kmemcg_schedule_work_after_rcu(struct rcu_head *head) { struct kmem_cache *s = container_of(head, struct kmem_cache, - memcg_params.deact_rcu_head); + memcg_params.rcu_head); - /* - * We need to grab blocking locks. Bounce to ->deact_work. The - * work item shares the space with the RCU head and can't be - * initialized eariler. - */ - INIT_WORK(&s->memcg_params.deact_work, kmemcg_deactivate_workfn); - queue_work(memcg_kmem_cache_wq, &s->memcg_params.deact_work); + INIT_WORK(&s->memcg_params.work, kmemcg_after_rcu_workfn); + queue_work(memcg_kmem_cache_wq, &s->memcg_params.work); } -/** - * slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a - * sched RCU grace period - * @s: target kmem_cache - * @deact_fn: deactivation function to call - * - * Schedule @deact_fn to be invoked with online cpus, mems and slab_mutex - * held after a sched RCU grace period. The slab is guaranteed to stay - * alive until @deact_fn is finished. This is to be used from - * __kmemcg_cache_deactivate(). - */ -void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, - void (*deact_fn)(struct kmem_cache *)) +static void kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s) { - if (WARN_ON_ONCE(is_root_cache(s)) || - WARN_ON_ONCE(s->memcg_params.deact_fn)) - return; + __kmemcg_cache_deactivate_after_rcu(s); +} + +static void kmemcg_cache_deactivate(struct kmem_cache *s) +{ + __kmemcg_cache_deactivate(s); if (s->memcg_params.root_cache->memcg_params.dying) return; @@ -750,8 +742,9 @@ void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, /* pin memcg so that @s doesn't get destroyed in the middle */ css_get(&s->memcg_params.memcg->css); - s->memcg_params.deact_fn = deact_fn; - call_rcu(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn); + WARN_ON_ONCE(s->memcg_params.work_fn); + s->memcg_params.work_fn = kmemcg_cache_deactivate_after_rcu; + call_rcu(&s->memcg_params.rcu_head, kmemcg_schedule_work_after_rcu); } void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) @@ -773,7 +766,7 @@ void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) if (!c) continue; - __kmemcg_cache_deactivate(c); + kmemcg_cache_deactivate(c); arr->entries[idx] = NULL; } mutex_unlock(&slab_mutex); @@ -866,11 +859,12 @@ static void flush_memcg_workqueue(struct kmem_cache *s) mutex_unlock(&slab_mutex); /* - * SLUB deactivates the kmem_caches through call_rcu. Make + * SLAB and SLUB deactivate the kmem_caches through call_rcu. Make * sure all registered rcu callbacks have been invoked. */ - if (IS_ENABLED(CONFIG_SLUB)) - rcu_barrier(); +#ifndef CONFIG_SLOB + rcu_barrier(); +#endif /* * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB diff --git a/mm/slub.c b/mm/slub.c index 2b9244529d76..195f61785c7d 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -4033,7 +4033,7 @@ int __kmem_cache_shrink(struct kmem_cache *s) } #ifdef CONFIG_MEMCG -static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s) +void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s) { /* * Called with all the locks held after a sched RCU grace period. @@ -4059,12 +4059,6 @@ void __kmemcg_cache_deactivate(struct kmem_cache *s) */ slub_set_cpu_partial(s, 0); s->min_partial = 0; - - /* - * s->cpu_partial is checked locklessly (see put_cpu_partial), so - * we have to make sure the change is visible before shrinking. - */ - slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu); } #endif /* CONFIG_MEMCG */