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=-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 12A56C3A59F for ; Thu, 29 Aug 2019 07:18:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBC312173E for ; Thu, 29 Aug 2019 07:18:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567063093; bh=izkLgyHOZlqRpcNCjrgJ70VvCJa6aJhURtvxKpY7S1g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=R1kt1LekIbaLQHkE1esHWxu2wqsiYxF3U9tyKgaK9PRRm1UP5MZ0iz7wvsnd+g286 90gmB1GNbAowKv5WngCR+nZ1nHpBT8hjXI/lDCzjFO7AKFLmFBv9DXrZjUinrGql+K h4bUJ6YHlKfNeFD15AzFzS/4U/mMc2v5VIdXYfwM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727413AbfH2HSK (ORCPT ); Thu, 29 Aug 2019 03:18:10 -0400 Received: from mx2.suse.de ([195.135.220.15]:34902 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725853AbfH2HSK (ORCPT ); Thu, 29 Aug 2019 03:18:10 -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 EA865B116; Thu, 29 Aug 2019 07:18:07 +0000 (UTC) Date: Thu, 29 Aug 2019 09:18:07 +0200 From: Michal Hocko To: Mina Almasry Cc: Mike Kravetz , shuah , David Rientjes , Shakeel Butt , Greg Thelen , Andrew Morton , khalid.aziz@oracle.com, open list , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, cgroups@vger.kernel.org, Aneesh Kumar , Michal =?iso-8859-1?Q?Koutn=FD?= , Tejun Heo , Johannes Weiner , Li Zefan Subject: Re: [PATCH v3 0/6] hugetlb_cgroup: Add hugetlb_cgroup reservation limits Message-ID: <20190829071807.GR28313@dhcp22.suse.cz> References: <20190826233240.11524-1-almasrymina@google.com> <20190828112340.GB7466@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org [Cc cgroups maintainers] On Wed 28-08-19 10:58:00, Mina Almasry wrote: > On Wed, Aug 28, 2019 at 4:23 AM Michal Hocko wrote: > > > > On Mon 26-08-19 16:32:34, Mina Almasry wrote: > > > mm/hugetlb.c | 493 ++++++++++++------ > > > mm/hugetlb_cgroup.c | 187 +++++-- > > > > This is a lot of changes to an already subtle code which hugetlb > > reservations undoubly are. > > For what it's worth, I think this patch series is a net decrease in > the complexity of the reservation code, especially the region_* > functions, which is where a lot of the complexity lies. I removed the > race between region_del and region_{add|chg}, refactored the main > logic into smaller code, moved common code to helpers and deleted the > duplicates, and finally added lots of comments to the hard to > understand pieces. I hope that when folks review the changes they will > see that! :) Post those improvements as standalone patches and sell them as improvements. We can talk about the net additional complexity of the controller much easier then. > > Moreover cgroupv1 is feature frozen and I am > > not aware of any plans to port the controller to v2. > > Also for what it's worth, if porting the controller to v2 is a > requisite to take this, I'm happy to do that. As far as I understand > there is no reason hugetlb_cgroups shouldn't be in cgroups v2, and we > see value in them. Talk to cgroups maintainers why the hugegetlb controller hasn't been enabled in v2. All I am saing is that v1 only features are really a hard sell. Even without adding a lot of code to hugetlb which is quite complex on its own. -- Michal Hocko SUSE Labs