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=0.1 required=3.0 tests=DATE_IN_PAST_03_06, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D257EC5B57D for ; Wed, 3 Jul 2019 01:13:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8F0320673 for ; Wed, 3 Jul 2019 01:13:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562116386; bh=7BKwrn5ZR0EvyKBoBdw71Sjqy+1SUbMyW6AzU7/ufH4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=HIocCK/1tNfnqgtTuQ05xZl4bOVEYB59k3YxxAl53wuJxP9vTFRenxGQwRDV4D3v9 vCA7kvhH10N9SH7iHem+CUGtzo/dG+NLpzjqBAhKcc2zwbg33GRPVsEvh0PzP7D4kF 5P314mOHXnoMaCfPToCOzc8ANZX3syC1RAo3VOzo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727327AbfGCBNF (ORCPT ); Tue, 2 Jul 2019 21:13:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:57308 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbfGCBNF (ORCPT ); Tue, 2 Jul 2019 21:13:05 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ED1AE218CA; Tue, 2 Jul 2019 21:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562103221; bh=7BKwrn5ZR0EvyKBoBdw71Sjqy+1SUbMyW6AzU7/ufH4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RBa6CBZoD/h1b3spSkXt/s5mk4/LF71sNM0q6jPS2dnne68logM7RJmnQeYqnoPlk We4S37hoCXN1vJ/SylpXLdidWn8wQovBsN3zWD/thJwRlA5V0kPWzkSRUxdgTRtCMR lCSW1e94ZmkPHXhQYrDUGU4rHNsLYjp0UCC4jn8o= Date: Tue, 2 Jul 2019 14:33:40 -0700 From: Andrew Morton To: Waiman Long Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , 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 Message-Id: <20190702143340.715f771192721f60de1699d7@linux-foundation.org> In-Reply-To: <78879b79-1b8f-cdfd-d4fa-610afe5e5d48@redhat.com> References: <20190702183730.14461-1-longman@redhat.com> <20190702130318.39d187dc27dbdd9267788165@linux-foundation.org> <78879b79-1b8f-cdfd-d4fa-610afe5e5d48@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Jul 2019 16:44:24 -0400 Waiman Long wrote: > On 7/2/19 4:03 PM, Andrew Morton wrote: > > On Tue, 2 Jul 2019 14:37:30 -0400 Waiman Long wro= te: > > > >> Currently, a value of '1" is written to /sys/kernel/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? > > > > Please fully describe the value of the proposed feature to or users.=20 > > Always. >=20 > Sure. Essentially, the sysfs shrink interface is not complete. It allows > the root cache to be shrunk, but not any of the memcg caches.=A0 But that doesn't describe anything of value. Who wants to use this, and why? How will it be used? What are the use-cases?