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=1.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT 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 2B59AC04AAF for ; Tue, 21 May 2019 05:01:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF84D21019 for ; Tue, 21 May 2019 05:01:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558414913; bh=SBlJXfUBXXFK65r3s5xX8606kKlKlqk3uqfNMpr45i4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=1sVRORO1u3rJKsWDcKl6ixJXAiKWtYjXL2qDM7w9PuCyWX4QdzyKsso8be6s4DT9i 0v6LpygHh+Q62FHKoQFDEz6MSJZIYz/2D5Skmk4R2WooqHC+6MU5OxJDxBxc90rr+Y fK49/LOYdMXZLEIbH3Ch0+NymLSg2ymoYDLjzZJA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727513AbfEUFBw (ORCPT ); Tue, 21 May 2019 01:01:52 -0400 Received: from mail-pf1-f173.google.com ([209.85.210.173]:46028 "EHLO mail-pf1-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725793AbfEUFBv (ORCPT ); Tue, 21 May 2019 01:01:51 -0400 Received: by mail-pf1-f173.google.com with SMTP id s11so8378989pfm.12 for ; Mon, 20 May 2019 22:01:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=QoDuJHrLBQ/xwGBwHKCt2IBJytG8/Ex5Sv/y0ADsw9A=; b=j6GM2Wd15hhYbHOpmjGikLz1Yeo8XKNvknmNfEyF4ygPaaXBNSh6MEOembaOV6xba5 5lgIbRbxvKNW2MBKsDZ5qYikCnCq5FQlHcx3r5v2Xt3nzvJlEkPTkTY0vitEKORsfrLJ t0G+0bT2uvVuXYIeWA/clAlNGdGrDJHUxBPTWTRWcM+epfdoB9ifCLdS8BYINhPU1y5o 74BaFoZ8ibyH+goPRw9iMY3cLhpRHuTt7b1qYg1e4Abi3JU/xfbsu1CimUBvZAX41rNv QurGjtazYmaLBIhndMYwtMMP9u3pAYR0PlvWjv6zwenkmsbJgigfQD6WYqpWgtn7tqTd 11jA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=QoDuJHrLBQ/xwGBwHKCt2IBJytG8/Ex5Sv/y0ADsw9A=; b=iwoaeUJD574V6JthGsDBcPK0GnFCzoVf3dxFIQweZHCvrGV8lN4LMbMKFESFhw1BJf VxeD6Fz1y9HTnfP1J6sUfwqJTEAbLAnd1/dJGhK8b23niueElhrHz3d1KJxECNgexFkU 9uIyIUWVOHxl0CEorRxuwxbmts+Iz3xG+wgLJFutn8a+x6F/Zt3y11SCcdlrw8u3qae2 7MwRMyp1sm1Gafxy+gT7zRFZ02JNf5cpcfCA77DDT4+aXEN42LuNUHk6oihx3G6jT0HY nz1sr6D8jFZV9Zl2sXOLnKA8UO2xivDB9Q2nkmzXU6cQa6ZbmKK6wC+t7rwmQB3EQ77N GSsA== X-Gm-Message-State: APjAAAWw8d9OuRcy8n/Do+T4X2qSnzV2fNhFgQceJvjRogpNTtnchRUE nv70AdSck97vNbygGw0DWTuG3Afg X-Google-Smtp-Source: APXvYqyJH0J5FSk3fdPjh9d4XeRJ+4EEk9eUbgIyEI9pQ/tWso7pSHIofovJWiwS4/R/xQ1KB0n76Q== X-Received: by 2002:aa7:8f2f:: with SMTP id y15mr74227321pfr.124.1558414910967; Mon, 20 May 2019 22:01:50 -0700 (PDT) Received: from google.com ([2401:fa00:d:0:98f1:8b3d:1f37:3e8]) by smtp.gmail.com with ESMTPSA id p13sm12382900pfq.69.2019.05.20.22.01.46 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 20 May 2019 22:01:49 -0700 (PDT) Date: Tue, 21 May 2019 14:01:44 +0900 From: Minchan Kim To: Matthew Wilcox Cc: Andrew Morton , LKML , linux-mm , Michal Hocko , Johannes Weiner , Tim Murray , Joel Fernandes , Suren Baghdasaryan , Daniel Colascione , Shakeel Butt , Sonny Rao , Brian Geffon Subject: Re: [RFC 0/7] introduce memory hinting API for external process Message-ID: <20190521050144.GK10039@google.com> References: <20190520035254.57579-1-minchan@kernel.org> <20190521014452.GA6738@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190521014452.GA6738@bombadil.infradead.org> 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 Mon, May 20, 2019 at 06:44:52PM -0700, Matthew Wilcox wrote: > On Mon, May 20, 2019 at 12:52:47PM +0900, Minchan Kim wrote: > > IMHO we should spell it out that this patchset complements MADV_WONTNEED > > and MADV_FREE by adding non-destructive ways to gain some free memory > > space. MADV_COLD is similar to MADV_WONTNEED in a way that it hints the > > kernel that memory region is not currently needed and should be reclaimed > > immediately; MADV_COOL is similar to MADV_FREE in a way that it hints the > > kernel that memory region is not currently needed and should be reclaimed > > when memory pressure rises. > > Do we tear down page tables for these ranges? That seems like a good True for MADV_COLD(reclaiming) but false for MADV_COOL(deactivating) at this implementation. > way of reclaiming potentially a substantial amount of memory. Given that consider refauting are spread out over time and reclaim occurs in burst, that does make sense to speed up the reclaiming. However, a concern to me is anonymous pages since they need swap cache insertion, which would be wasteful if they are not reclaimed, finally.