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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 19B0FC63798 for ; Mon, 23 Nov 2020 17:15:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD13C2075A for ; Mon, 23 Nov 2020 17:15:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="LlizgBvV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390262AbgKWRPG (ORCPT ); Mon, 23 Nov 2020 12:15:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733152AbgKWRPG (ORCPT ); Mon, 23 Nov 2020 12:15:06 -0500 Received: from mail-qk1-x735.google.com (mail-qk1-x735.google.com [IPv6:2607:f8b0:4864:20::735]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1C9EC0613CF for ; Mon, 23 Nov 2020 09:15:04 -0800 (PST) Received: by mail-qk1-x735.google.com with SMTP id u184so3068308qkf.3 for ; Mon, 23 Nov 2020 09:15:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=kvBGtFT9p+lNN1wnKJ27cKqo+mVo01rfpUdq4ICcnCo=; b=LlizgBvVF6PIc8dJ2FLojBbEJZlK9COaX2vyuLyDC9PG/wNw623YnlNybC47WpFuiv PtYA6ubE3P7QBehYPVwSYRflyWgHrmkjugD+nCjHntymPepmKyLUTwugEfYW3Nw2P2SP hrxib78j7pTNqBYSvjBMrV4x4viFURYxEkgDpKYhm9Y92yo6qzxSvybp8ECcjZpITAZf qvC3hDeripEmGZQW/kh5aGtYhMpLHrN0Q+LEDhznEStp4gDxzc8nVB5YJ8yF6rmFEmEQ HmH6JVP9m7vwxphnbgUdVGbN4ebQq4wbUeA/lVItKFo6EAa2EvHcBZ7mmhOo3Tww4s3V OQWA== 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; bh=kvBGtFT9p+lNN1wnKJ27cKqo+mVo01rfpUdq4ICcnCo=; b=kpf7rlPYA1OfglvOvoRJgXw8jm74z6ki5r4BmQuQS2spKGqQLR7+oUuuS4uS+9j7L/ 3ThisOm0oQ9ZdSl0pSc2wBdfZAa2j+484WxZP32Wgc+ud5YoDSzuZvFJc+/CCnw2GjDA jqLG6SvHC09tyF7+DSJT39pRBrtgiEVG9kCyA0iOUx2PTI0kw7XAm7zfu+NzOidbFfrV 04Of4O7IZRZycsLjzotnRBAcrO7QIbkyvc+wlpccytUmUa4wFG9JnmmK+ouKTH0YqGVW g46Is7PdVj9xDXtdLT3xbW8OdG+/Lx3mebWBJ2fH/DZcNMf/dVDgjlxx2xRrBTcMeJnt 4spA== X-Gm-Message-State: AOAM530RXWCdNIjHpmhS079EO7/IeXg33oPnEotMWl6PGSZR6W1XYqhq W5U5FU8nMYXuOHi5/HnDwpRJdg== X-Google-Smtp-Source: ABdhPJzzfbE7crG1AGzIBt80F3rqZ7Bc00frJCBVtjv7Axg3xfzI1getpXUfvt7Qln7neCKN55RBtw== X-Received: by 2002:a05:620a:ec2:: with SMTP id x2mr484822qkm.328.1606151704157; Mon, 23 Nov 2020 09:15:04 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id z133sm10523570qka.20.2020.11.23.09.15.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Nov 2020 09:15:03 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1khFQc-00A6rX-Ou; Mon, 23 Nov 2020 13:15:02 -0400 Date: Mon, 23 Nov 2020 13:15:02 -0400 From: Jason Gunthorpe To: Pavel Tatashin Cc: Michal Hocko , linux-mm , Andrew Morton , Vlastimil Babka , LKML , David Hildenbrand , Oscar Salvador , Dan Williams , Sasha Levin , Tyler Hicks , Joonsoo Kim , sthemmin@microsoft.com Subject: Re: Pinning ZONE_MOVABLE pages Message-ID: <20201123171502.GX244516@ziepe.ca> References: <20201123090129.GD27488@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 23, 2020 at 11:06:21AM -0500, Pavel Tatashin wrote: > What I mean here is allowing users to guarantee that the page's PA is > going to stay the same. Sort of a stronger mlock. Mlock only > guarantees that the page is not swapped, but something like You've just described get/pin_user_pages(), that is exactly what it is for. I agree with the other emails, ZONE_MOVABLE needs to be reconciled with FOLL_LONGTERM - most likely by preventing ZONE_MOVABLE pages from being returned. This will need migration like CMA does and the point about faulting is only an optimization to prevent fault then immediate migration. Jason