From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB5B9C06513 for ; Tue, 2 Jul 2019 19:15:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8FD392186A for ; Tue, 2 Jul 2019 19:15:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8FD392186A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2D5FA6B0005; Tue, 2 Jul 2019 15:15:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2870F8E0003; Tue, 2 Jul 2019 15:15:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 175908E0001; Tue, 2 Jul 2019 15:15:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) by kanga.kvack.org (Postfix) with ESMTP id EA1656B0005 for ; Tue, 2 Jul 2019 15:15:56 -0400 (EDT) Received: by mail-qt1-f197.google.com with SMTP id s22so17323636qtb.22 for ; Tue, 02 Jul 2019 12:15:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:organization:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=Bc+JKVicEphiO115dgnlLTyRJLHBC0GoGOV/NuafloQ=; b=tlIpEsESDR2uluPFQqN2HhrC9Y2DT9yuDsCLr/HCmoFfZfESJ9vcqZBVa1WUJwgGIV yBAjQEVpaggViW3h+b2Nz3EYIrEcxZaCWKhVDTtw3SD8jPYJt5VKxBPTC1IuuUOdLs7F IneWW30O80qZdTbJwCSGVVQIPqduwB/Ih7IXRvffzQRIIv2mSOEn8bLv2K64VpnXoUzp q8LS2XmnFm9kV20oe9qdEKW5/ZptXyJrwkXTlAs04Yc7Yaa8HiklrOtHsEcg73NOQPm8 plIHZOp+GVvuyx/AKPpVxS6eXs1SFt0Z+Ed7TTMXfMH6auSByzme7KzKxACCMY4PrrO8 kyMw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of longman@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=longman@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: APjAAAVxHvanHQZHbrU5S3CmPks+qW0WNVzO4HdpIJwIF08Sf6e5A4oB nLTkpFlfaeecRzJO8aJ/uwKbQXDDHURXquzfp31eUHYzEkkCJ/VCzvUlEoWf/DPfowiT/rRuShl tPE3sxzdTLjRSvI1uABY5634yqBuWCdGhPM+NNPQEqMD3XgFBxXIbTex6CMdndNWgzw== X-Received: by 2002:ac8:877:: with SMTP id x52mr26607854qth.328.1562094956720; Tue, 02 Jul 2019 12:15:56 -0700 (PDT) X-Google-Smtp-Source: APXvYqyhpHh+poq7HYP1UXgbFB4oFt123B7c7+y7heKFsn8Gtmg8w4yTLUW7hkYn4ppHGlPmJOWI X-Received: by 2002:ac8:877:: with SMTP id x52mr26607808qth.328.1562094956067; Tue, 02 Jul 2019 12:15:56 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1562094956; cv=none; d=google.com; s=arc-20160816; b=yPB/KxLstU94fIwtknB7yLXueYQBkKnKkUwTuwrGjYvqh9ad8DPvDujdK17yG+3JId x0cpbqzXJ99Mv+/PjmYIfG15thxOco/keGc/Kv8JMjmNDnhUkkZ381eNXApfwyff+r0V 34gyTQlzMMQKWs0zsIZlTUPpU2FqlXY41pwi2ydqwPi2Nl/1ScgXGU+dxoWXqcgI3B11 3I5S1sfUDHpmjmSb9y3VVHoBK06JZF+793MJcd3RhWXg7PGlQOp1AipQsQphuMYblWS2 e9RnX18Tl8K27mehAQhwsFc6lf/LRwn1Jc0E2vUVn5pUh/fm5o7sy1Fd8i83uBtq9vuq zS0w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:organization:from:references:cc:to :subject; bh=Bc+JKVicEphiO115dgnlLTyRJLHBC0GoGOV/NuafloQ=; b=qXVMyE6rf3cQoDB0RYn/F1osGXXqwmkfQ5igJdSiHEp7vTuRJyXTGtXtcgfkmB15Hx PyZS7g2HgvbmJ+o8BC+2AE0eGmFEOpajFn7+MJGwyi1fwk9YnZmJhUWXSt/U/GDf8s49 NZEYP3m9YzF7SNWVurGUdFKdBxWfvkfg+hpoosQFD/0O2/jQ1OjLfjjz3PmaFU0dMO0/ cI19VvQ+PCQrJS02X1pUbqGhCqSzEtNkPGTqieP/lsxrMNJFtV832irR9kwqn65yvzFu aGvVpk6nkJ4rfhFq+6koY1WI+QTWirKnJb4ZRLg6qr1omk019TdOZ2EBOFVkd3FEzypC 0eNQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of longman@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=longman@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id t42si77259qtc.163.2019.07.02.12.15.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Jul 2019 12:15:56 -0700 (PDT) Received-SPF: pass (google.com: domain of longman@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of longman@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=longman@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 25FA9C057F2E; Tue, 2 Jul 2019 19:15:50 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-160.bos.redhat.com [10.18.17.160]) by smtp.corp.redhat.com (Postfix) with ESMTP id AA0471347B; Tue, 2 Jul 2019 19:15:42 +0000 (UTC) Subject: Re: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg caches To: David Rientjes 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 References: <20190702183730.14461-1-longman@redhat.com> From: Waiman Long Organization: Red Hat Message-ID: <34af4938-f472-9d9b-e615-397217023004@redhat.com> Date: Tue, 2 Jul 2019 15:15:42 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 02 Jul 2019 19:15:55 +0000 (UTC) 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 7/2/19 3:09 PM, David Rientjes wrote: > 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. You are right. I will reword the text to make it clearer. >> 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. It will depends on how many memcg caches are there. Actually, I have been thinking about using the show method to show the time spent in the last shrink operation. I am just not sure if it is worth doing. What do you think? -Longman