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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,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 1F53EC04AAF for ; Tue, 21 May 2019 06:26:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D9D21217D7 for ; Tue, 21 May 2019 06:26:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9D21217D7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 658D36B0005; Tue, 21 May 2019 02:26:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 607DE6B0006; Tue, 21 May 2019 02:26:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F6E66B0007; Tue, 21 May 2019 02:26:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id 046606B0005 for ; Tue, 21 May 2019 02:26:31 -0400 (EDT) Received: by mail-ed1-f71.google.com with SMTP id r20so29009341edp.17 for ; Mon, 20 May 2019 23:26:30 -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:date:from:to :cc:subject:message-id:references:mime-version:content-disposition :in-reply-to:user-agent; bh=CzppJZV98yTh7mhgyQj10DGJb6ANdtEoPKV4ajF34Zc=; b=n8MytUse/7WmvES3jIExSVYwDxTiNvkiJOVHBGYfrtN+AP9C2dU3EkHoEA/bFzSkvh 4KY3QcZKcdkXPVRYhxHnGvvjJxFCQbILgcDjBOEDqVDkOQuUpEszA3UgAkm4Ot0Y3Lp6 mSHjOg9yPC7YgOT5AO3v64vGoqIm//qoN7E38WnEfZN5Uv3l+ng8l4KrMRRaxWVno+4g ub8dpqmsaJxg9RpCCwu3uX7RwUCbgtxfOe8uB9DWyuxgbnlrPzRTDcbB5Nq5s3rH//09 iu1pcB7rcUAOjjGOBmMCAw/6ALMaxn1vUVxOJChM8tEbvfsiDL2gUMs8jgaTFhj8s/kx 6uZg== X-Original-Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Gm-Message-State: APjAAAXDzs89nbeD8YkMi8H5U+QtqA2RXXE/En3PxCvfHQPennVZHiZY oYYw6jLua/ezXy85bwUgLvlnKam17eU9QCxQObVS5jAfPr+c+rYibE3gYNvR57QHrsrXkgNOINA cpKDhNYpYaH641F/Wb3kaKCk72pMVpsa+9KbgL1LogYxfbF54mXHRKOF43XuNqFA= X-Received: by 2002:a50:e705:: with SMTP id a5mr80289031edn.270.1558419990601; Mon, 20 May 2019 23:26:30 -0700 (PDT) X-Google-Smtp-Source: APXvYqwfxFxwDDFoj1wm/9mmW7onRAk7j7cQjtyt4guAnx9RtI1ER7NoXM1ewMSASysCletLBnYH X-Received: by 2002:a50:e705:: with SMTP id a5mr80288984edn.270.1558419989915; Mon, 20 May 2019 23:26:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1558419989; cv=none; d=google.com; s=arc-20160816; b=RPy4/dCA7CgdnmmIVcONfDspdawypFzXv+NUa3QQr9OxMlzxgZnWL8bLerrLfSM5zj FzpiE7xebiu2eBSK1Az2HSYF2ol7e705tyT+qjGfyCnV968E2XS7NMFDVubVCHNbb1fl gtYd2hJ3BkAtN0NNRQBHKHx8UzCsMw7yp+hVkbf9iwdiFU8jtVq2guDXZzLcERjBtL6U uJeyZ2HV9QjcUwAWDV184cxDDCaFsgPrtk398G5wFvtMgTJX7fX5zY9SS6B3LQcxmKNx k/sdFCSCy9REMiKLQb5k6FA6u1d69T/ln0MRotaw+u77eN463NcvDcAmy0LR0xiQ9Xwh efdg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date; bh=CzppJZV98yTh7mhgyQj10DGJb6ANdtEoPKV4ajF34Zc=; b=SJ2aWTv8LqILX5fZyEMOYaLHjzkWYYnTgkn0KlnbX6YY0TaKPodwdhpL6WTQkxpSya dA5NaOHunVfJpGVncZL3I8x/xHDCLvl1jmUXaEMi0Z3f3QlNeKOQu4P7hdhZSgGVfMmf l9DDbrVIeNBK0Qg4lSsE80x5u32DjeJk6+KJ/rhA5KFTHVDeYRO18PJ/U8vHS+zMf11W fXHQGFGpTB6sv1H40b6ec176ngFWO6RgaJMg8gY1rOeUFVC3xUwI5eg6nlmEO1KvPIyC soJ6ofVXgDOOBKSqQ0DQhkLuXPTcB/4lnavQLa7TQI1Zzv2+CDb6cIkHzi7LilIYYLLt p8Fw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id cw5si6291762ejb.382.2019.05.20.23.26.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 May 2019 23:26:29 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org 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 7FB96AE08; Tue, 21 May 2019 06:26:29 +0000 (UTC) Date: Tue, 21 May 2019 08:26:28 +0200 From: Michal Hocko To: Minchan Kim Cc: Andrew Morton , LKML , linux-mm , Johannes Weiner , Tim Murray , Joel Fernandes , Suren Baghdasaryan , Daniel Colascione , Shakeel Butt , Sonny Rao , Brian Geffon , linux-api@vger.kernel.org Subject: Re: [RFC 7/7] mm: madvise support MADV_ANONYMOUS_FILTER and MADV_FILE_FILTER Message-ID: <20190521062628.GE32329@dhcp22.suse.cz> References: <20190520035254.57579-1-minchan@kernel.org> <20190520035254.57579-8-minchan@kernel.org> <20190520092801.GA6836@dhcp22.suse.cz> <20190521025533.GH10039@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190521025533.GH10039@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Tue 21-05-19 11:55:33, Minchan Kim wrote: > On Mon, May 20, 2019 at 11:28:01AM +0200, Michal Hocko wrote: > > [cc linux-api] > > > > On Mon 20-05-19 12:52:54, Minchan Kim wrote: > > > System could have much faster swap device like zRAM. In that case, swapping > > > is extremely cheaper than file-IO on the low-end storage. > > > In this configuration, userspace could handle different strategy for each > > > kinds of vma. IOW, they want to reclaim anonymous pages by MADV_COLD > > > while it keeps file-backed pages in inactive LRU by MADV_COOL because > > > file IO is more expensive in this case so want to keep them in memory > > > until memory pressure happens. > > > > > > To support such strategy easier, this patch introduces > > > MADV_ANONYMOUS_FILTER and MADV_FILE_FILTER options in madvise(2) like > > > that /proc//clear_refs already has supported same filters. > > > They are filters could be Ored with other existing hints using top two bits > > > of (int behavior). > > > > madvise operates on top of ranges and it is quite trivial to do the > > filtering from the userspace so why do we need any additional filtering? > > > > > Once either of them is set, the hint could affect only the interested vma > > > either anonymous or file-backed. > > > > > > With that, user could call a process_madvise syscall simply with a entire > > > range(0x0 - 0xFFFFFFFFFFFFFFFF) but either of MADV_ANONYMOUS_FILTER and > > > MADV_FILE_FILTER so there is no need to call the syscall range by range. > > > > OK, so here is the reason you want that. The immediate question is why > > cannot the monitor do the filtering from the userspace. Slightly more > > work, all right, but less of an API to expose and that itself is a > > strong argument against. > > What I should do if we don't have such filter option is to enumerate all of > vma via /proc//maps and then parse every ranges and inode from string, > which would be painful for 2000+ vmas. Painful is not an argument to add a new user API. If the existing API suits the purpose then it should be used. If it is not usable, we can think of a different way. -- Michal Hocko SUSE Labs