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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 3294EC04AAF for ; Tue, 21 May 2019 15:33:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 054C6217D8 for ; Tue, 21 May 2019 15:33:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="rnqXgMMh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728474AbfEUPdO (ORCPT ); Tue, 21 May 2019 11:33:14 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:33019 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728053AbfEUPdO (ORCPT ); Tue, 21 May 2019 11:33:14 -0400 Received: by mail-pf1-f193.google.com with SMTP id z28so9283142pfk.0 for ; Tue, 21 May 2019 08:33:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8JdJVvAGyNC8PSXsjfUN8u+zmKF1hLoAAqIvD329Mjs=; b=rnqXgMMhyVETxYuovuKic/EJW9jX8R4OBSqbR8Ns4TCHRCgBy8Sb1k0zAYZ59/J94S 6Iy/Sm1itRyXny9cYzoIGNEtsR/bRvQoGUIh852eQWPsq5aGavHDwD0W6w2MpswU3Coc y5ymxRJjWQkhYAf0ob40InCjHd1X+a9yIvvmOF7KY43VbWNgKA5IAyDiqwOLKg6lUoqL 77/P03tIKEXYXyvDAoD5fDljlvUS67qiJRndivR1QEvDomd3Shrbs0vyHhTytRp2wLB5 JUozEO+U/NShOuhdDwTC0JpBQoX+2f8Vk6Ht9mI5S7oyQrykqElGO8iOhesf6Ir1faQS V5OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8JdJVvAGyNC8PSXsjfUN8u+zmKF1hLoAAqIvD329Mjs=; b=HJa39vQ4pnwB2EAlYDYqiG3c3KHxCzz3+f6374DMf8lIVTQTXVr2sBGYKMjVvbeBxq R5ujyDNQ6UDgARWbBmOu/iAzIebdQIy5UfEkBInmmKZVkmNSsPfYumml1ZvyGyKrSaS4 mE8OjOw/5OlxJIQneehAzPgMAHk0crPSSAwcAyupWYionLqLx85KH/IQlgS8DT2vVISs NDeQKX9SENi3wv2KLJHyR3tpaybCoGoFIQ0AU9QMPN2Y5CgS6uH6e6sVU0wHw/bbFc3i rgDLI7ExWJbNqBVLOx4ALZ/dgoD8HSgNyQtC3i2iNrIfEbe2AbkOQjqbUJVAjCh00WPf basQ== X-Gm-Message-State: APjAAAWp10shjTR/U5BtLZF0vPgcYY7E8UrVqEXZusPlDP9bRli88cfT nlMSOwvNjy53UKqyL9HSCPvILA== X-Google-Smtp-Source: APXvYqwlng0s4LJPDKCEGz+dJqb/FMYHQKwaVN6ia1yxZapGNrVbL/8WU/wAPFu2zQ4PE5OMy57Bpw== X-Received: by 2002:a63:d901:: with SMTP id r1mr45310557pgg.271.1558452793234; Tue, 21 May 2019 08:33:13 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::2:5a76]) by smtp.gmail.com with ESMTPSA id 135sm38967196pfb.97.2019.05.21.08.33.11 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 21 May 2019 08:33:12 -0700 (PDT) Date: Tue, 21 May 2019 11:33:10 -0400 From: Johannes Weiner To: Minchan Kim Cc: Michal Hocko , Andrew Morton , LKML , linux-mm , 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: <20190521153310.GA3218@cmpxchg.org> 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/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 21, 2019 at 11:55:33AM +0900, 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. Just out of curiosity, how do you get to 2000+ distinct memory regions in the address space of a mobile app? I'm assuming these aren't files, but rather anon objects with poor grouping. Is that from guard pages between individual heap allocations or something?