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[209.85.220.65]) by mx.google.com with SMTPS id m93sor4477882pje.1.2019.07.02.12.09.29 for (Google Transport Security); Tue, 02 Jul 2019 12:09:29 -0700 (PDT) Received-SPF: pass (google.com: domain of rientjes@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=gf9AynaR; spf=pass (google.com: domain of rientjes@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=rientjes@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=7MbyDYqaqvSFQxOK+144mOVh5/lF6H2bN9YDe1mqXsE=; b=gf9AynaRipCPNwL4fqUj1Kgn+M7Ben9Z5cpa9swnWQpDwgucDeCPC01FXDrDkJ6uY0 NSSCVdOhd5rccsRnUlWJ3ltnJlP3CpkB1Z4l9dmROza6n7s9SAwfvaIofJOW+IwiIL9D rzCy4GxgcbCFYjvq+xCwL1krM+FxBF9je/WbpobhrRQYa2zVlcD4/XurltNaGbLN9rvS ede+qAXNcAhTef1SGO6BUKHn/q2Nvk/NaAg2z6OGVU+ZBiu/dqAHr+Q4jibrC9xFD2D6 NHug/qhQbzlj3lSwkRlT7jw6/nXJDtW+gVpRHI/qNjTEGJuGadXUqOSUe5XpcXv/SWGi fj7w== X-Google-Smtp-Source: APXvYqx9wyjGr3gEZi8btnw1XM/Out5qiZEDMv6+jCbc/ZJawA+a4NDQhc2TqwqowTNEDVgPQ/xJhA== X-Received: by 2002:a17:90a:338b:: with SMTP id n11mr7294382pjb.21.1562094569110; Tue, 02 Jul 2019 12:09:29 -0700 (PDT) Received: from [2620:15c:17:3:3a5:23a7:5e32:4598] ([2620:15c:17:3:3a5:23a7:5e32:4598]) by smtp.gmail.com with ESMTPSA id y22sm29677631pfo.39.2019.07.02.12.09.27 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 02 Jul 2019 12:09:27 -0700 (PDT) Date: Tue, 2 Jul 2019 12:09:27 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Waiman Long cc: Christoph Lameter , Pekka Enberg , Joonsoo Kim , Andrew Morton , Alexander Viro , Jonathan Corbet , Luis Chamberlain , Kees Cook , Johannes Weiner , Michal Hocko , Vladimir Davydov , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Roman Gushchin , Shakeel Butt , Andrea Arcangeli Subject: Re: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg caches In-Reply-To: <20190702183730.14461-1-longman@redhat.com> Message-ID: References: <20190702183730.14461-1-longman@redhat.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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: On Tue, 2 Jul 2019, Waiman Long wrote: > diff --git a/Documentation/ABI/testing/sysfs-kernel-slab b/Documentation/ABI/testing/sysfs-kernel-slab > index 29601d93a1c2..2a3d0fc4b4ac 100644 > --- a/Documentation/ABI/testing/sysfs-kernel-slab > +++ b/Documentation/ABI/testing/sysfs-kernel-slab > @@ -429,10 +429,12 @@ KernelVersion: 2.6.22 > Contact: Pekka Enberg , > Christoph Lameter > Description: > - The shrink file is written when memory should be reclaimed from > - a cache. Empty partial slabs are freed and the partial list is > - sorted so the slabs with the fewest available objects are used > - first. > + A value of '1' is written to the shrink file when memory should > + be reclaimed from a cache. Empty partial slabs are freed and > + the partial list is sorted so the slabs with the fewest > + available objects are used first. When a value of '2' is > + written, all the corresponding child memory cgroup caches > + should be shrunk as well. All other values are invalid. > This should likely call out that '2' also does '1', that might not be clear enough. > What: /sys/kernel/slab/cache/slab_size > Date: May 2007 > diff --git a/mm/slab.h b/mm/slab.h > index 3b22931bb557..a16b2c7ff4dd 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -174,6 +174,7 @@ 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 *); > +int kmem_cache_shrink_all(struct kmem_cache *s); > > struct seq_file; > struct file; > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 464faaa9fd81..493697ba1da5 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -981,6 +981,49 @@ int kmem_cache_shrink(struct kmem_cache *cachep) > } > EXPORT_SYMBOL(kmem_cache_shrink); > > +/** > + * kmem_cache_shrink_all - shrink a cache and all its memcg children > + * @s: The root cache to shrink. > + * > + * Return: 0 if successful, -EINVAL if not a root cache > + */ > +int kmem_cache_shrink_all(struct kmem_cache *s) > +{ > + struct kmem_cache *c; > + > + if (!IS_ENABLED(CONFIG_MEMCG_KMEM)) { > + kmem_cache_shrink(s); > + return 0; > + } > + if (!is_root_cache(s)) > + return -EINVAL; > + > + /* > + * The caller should have a reference to the root cache and so > + * we don't need to take the slab_mutex. We have to take the > + * slab_mutex, however, to iterate the memcg caches. > + */ > + get_online_cpus(); > + get_online_mems(); > + kasan_cache_shrink(s); > + __kmem_cache_shrink(s); > + > + mutex_lock(&slab_mutex); > + for_each_memcg_cache(c, s) { > + /* > + * Don't need to shrink deactivated memcg caches. > + */ > + if (s->flags & SLAB_DEACTIVATED) > + continue; > + kasan_cache_shrink(c); > + __kmem_cache_shrink(c); > + } > + mutex_unlock(&slab_mutex); > + put_online_mems(); > + put_online_cpus(); > + return 0; > +} > + > bool slab_is_available(void) > { > return slab_state >= UP; I'm wondering how long this could take, i.e. how long we hold slab_mutex while we traverse each cache and shrink it. Acked-by: David Rientjes