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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 79082C282DD for ; Thu, 18 Apr 2019 14:09:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 442A521479 for ; Thu, 18 Apr 2019 14:09:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JyY+dwTc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389358AbfDROJ4 (ORCPT ); Thu, 18 Apr 2019 10:09:56 -0400 Received: from mail-lf1-f66.google.com ([209.85.167.66]:46503 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388346AbfDROJz (ORCPT ); Thu, 18 Apr 2019 10:09:55 -0400 Received: by mail-lf1-f66.google.com with SMTP id k18so1725425lfj.13 for ; Thu, 18 Apr 2019 07:09:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=M5siCfHP6BRRv+5HIBdrYDPCmhboYZvbHLTv7FcSa9I=; b=JyY+dwTc08oWjbHxleqxC0ncbbwBF4oMaUwb7ZCNU2WOmjt/quOO1tXrYYzyCyutWC MkvSFQRQoEJiuaxY+6kKHQ2sPvWcr/lTFjEAPqtPCCw6/sdbzvAQtu3yULUJXzxjtibv 8k+Bw0sQElny79mVcnmTijLpGjhiWs5PBh+zGVPdwy55UvoYI8pQh9iz4EHXM7qIkVQ4 BP2CMdn13gGWO3tBbgNChg+k4K5HlKLv9mwaxLirITdao27RB6hCdgcr46bV/al1mi3c OFJDIPBad2L1bYlzkHvi0VOYFEe+orW4Z6SP+qxgZvI6KDeMcCsUYeO+dTau1Y0x0oCx vcfg== 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:content-transfer-encoding :in-reply-to:user-agent; bh=M5siCfHP6BRRv+5HIBdrYDPCmhboYZvbHLTv7FcSa9I=; b=FBvAsxp7POj8TmE/Zlgt9LpRM72ZkRJNEhS58PSNwQwmM1sBfc4uQwO8Rdo7eQtGw1 oIHZhiHJqDz3Z8Kyf5o8lY8ccOHrlhq8/kBPk66seKTVwZc/bjC3KwYW7mJvtrz9+3ak yofTuZ/OxWYUUBTwQfEoyyvYG1oP5d294CYP8GQ/yLAp2gqMIVGF1wdORFUAwrNx1Pbt NKSa5iC0HqIab+Yq0ZB7SWlJkKbWa7FeJ4mFC+d1/KJg3/48h3s0JGgfDsWAQm5wJScy BZ3qClzox9LLQFfAAiLpifzBAyInEppacN+I8BrRH6hKDI/LoRPllIvDouH9Rg6k0K3u Bgsw== X-Gm-Message-State: APjAAAWT+mpLg6SpOZqIBLTxG/SkzEixeXeT5WjtEvzQmdnldyn7m3BT lujtjQFEo1nQoOa1r2DJ120= X-Google-Smtp-Source: APXvYqzrj4shwzX3in9UPpImegqkTdLb+e4i4bJgo5k2iLRrydA3y8BLZAB2Obk207TGMdal3y75qQ== X-Received: by 2002:a19:f001:: with SMTP id p1mr9821667lfc.27.1555596593484; Thu, 18 Apr 2019 07:09:53 -0700 (PDT) Received: from uranus.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id 30sm471858lfr.22.2019.04.18.07.09.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 18 Apr 2019 07:09:52 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id 06858460E0B; Thu, 18 Apr 2019 17:09:52 +0300 (MSK) Date: Thu, 18 Apr 2019 17:09:51 +0300 From: Cyrill Gorcunov To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: mhocko@kernel.org, akpm@linux-foundation.org, arunks@codeaurora.org, brgl@bgdev.pl, geert+renesas@glider.be, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mguzik@redhat.com, rppt@linux.ibm.com, vbabka@suse.cz, Laurent Dufour Subject: Re: [PATCH] prctl_set_mm: downgrade mmap_sem to read lock Message-ID: <20190418140951.GH3040@uranus.lan> References: <20190417145548.GN5878@dhcp22.suse.cz> <20190418135039.19987-1-mkoutny@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190418135039.19987-1-mkoutny@suse.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 18, 2019 at 03:50:39PM +0200, Michal Koutný wrote: > I learnt, it's, alas, too late to drop the non PRCTL_SET_MM_MAP calls > [1], so at least downgrade the write acquisition of mmap_sem as in the > patch below (that should be stacked on the previous one or squashed). > > Cyrill, you mentioned lock changes in [1] but the link seems empty. Is > it supposed to be [2]? That could be an alternative to this patch after > some refreshments and clarifications. Yes, seems so. From a glance the patch shold be ok. Michal will review it more carefully today. Thanks!