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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 4E6DAC43387 for ; Thu, 10 Jan 2019 09:57:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E3C02177B for ; Thu, 10 Jan 2019 09:57:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547114276; bh=8ozcJw3V70/jjGf+5znbTC2qfaYowAqjoDFNwItU1d4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=bBOZC+L4uUGBu3/OsL/QDmDDfgO86BUma4KIxqoN4rQDoE04n7MmRlxW7Ozgg/ZT3 K8NLOuV/VD6fEgt9fKsYuBNlPjWP5HIsaB6MXPm/b0Pnt8v7aXBszdPVuwd78byXZH F+d6FiALpWgFKjzs7URzSrYh4gA2k6I6yfK4c9Qk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728068AbfAJJ5z (ORCPT ); Thu, 10 Jan 2019 04:57:55 -0500 Received: from mx2.suse.de ([195.135.220.15]:34416 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727825AbfAJJ5y (ORCPT ); Thu, 10 Jan 2019 04:57:54 -0500 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 8D836AC4B; Thu, 10 Jan 2019 09:57:53 +0000 (UTC) Date: Thu, 10 Jan 2019 10:57:52 +0100 From: Michal Hocko To: Kirill Tkhai Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, josef@toxicpanda.com, jack@suse.cz, hughd@google.com, darrick.wong@oracle.com, aryabinin@virtuozzo.com, guro@fb.com, mgorman@techsingularity.net, shakeelb@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/3] mm: Reduce IO by improving algorithm of memcg pagecache pages eviction Message-ID: <20190110095752.GK31793@dhcp22.suse.cz> References: <154703479840.32690.6504699919905946726.stgit@localhost.localdomain> <20190109141113.GW31793@dhcp22.suse.cz> <20190109171021.GY31793@dhcp22.suse.cz> <3d4f4c83-44c9-c6d5-8dbe-c42a47e6c2bd@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3d4f4c83-44c9-c6d5-8dbe-c42a47e6c2bd@virtuozzo.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 10-01-19 12:42:02, Kirill Tkhai wrote: [...] > In general, I think a some time useful design is not a Bible, that nobody > is allowed to change. We should not limit us in something, in case of this > has a sense and may be useful. This is just a note in general. But any semantic exported to the userspace and real application depending on it is carved in stone for ever. And this is the case here I am afraid. So if we really need some sort of soft unmapping or reparenting a memory from a memcg then we really need to find a different way. I do not see a straightforward way right now TBH. -- Michal Hocko SUSE Labs