From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=FHjv=VA=vger.kernel.org=linux-kernel-owner@kernel.org>
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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,
	USER_AGENT_SANE_1 autolearn=no 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 B2667C5B578
	for <linux-kernel@archiver.kernel.org>; Wed,  3 Jul 2019 06:56:35 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id 7BB9321882
	for <linux-kernel@archiver.kernel.org>; Wed,  3 Jul 2019 06:56:35 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;
	s=default; t=1562136995;
	bh=UVvViCJmyqCg1rZrFFcxSkaMIR4773fGFl0aFVqfJtU=;
	h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From;
	b=fr7JcJD4UbeW8IRnmmQn0yD6u/S8nhUQEEFcwFY0VhnRb6B1Ffo5ArsJGnr4ebFGV
	 IQ/8+Y/Wc/EW1hOUOrvfp2IqlRD0ozfN8ltDBTgRkV2zCoORLNG4pKBg8EYgbgMu2m
	 7aN6EqQYzvs56kkdED3GcC+dUhsKeT599C0h6IPo=
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1727116AbfGCG4e (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Wed, 3 Jul 2019 02:56:34 -0400
Received: from mx2.suse.de ([195.135.220.15]:42086 "EHLO mx1.suse.de"
        rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
        id S1726490AbfGCG4e (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 3 Jul 2019 02:56:34 -0400
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
Received: from relay2.suse.de (unknown [195.135.220.254])
        by mx1.suse.de (Postfix) with ESMTP id 84525AF84;
        Wed,  3 Jul 2019 06:56:32 +0000 (UTC)
Date:   Wed, 3 Jul 2019 08:56:28 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Waiman Long <longman@redhat.com>
Cc:     Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Jonathan Corbet <corbet@lwn.net>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>, 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 <guro@fb.com>,
        Shakeel Butt <shakeelb@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH] mm, slab: Extend slab/shrink to shrink all the memcg
 caches
Message-ID: <20190703065628.GK978@dhcp22.suse.cz>
References: <20190702183730.14461-1-longman@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190702183730.14461-1-longman@redhat.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue 02-07-19 14:37:30, Waiman Long wrote:
> Currently, a value of '1" is written to /sys/kernel/slab/<slab>/shrink
> file to shrink the slab by flushing all the per-cpu slabs and free
> slabs in partial lists. This applies only to the root caches, though.
> 
> Extends this capability by shrinking all the child memcg caches and
> the root cache when a value of '2' is written to the shrink sysfs file.

Why do we need a new value for this functionality? I would tend to think
that skipping memcg caches is a bug/incomplete implementation. Or is it
a deliberate decision to cover root caches only?
-- 
Michal Hocko
SUSE Labs