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=-14.8 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1, USER_IN_DEF_DKIM_WL 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 13F15C433DB for ; Mon, 28 Dec 2020 06:45:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3844207BC for ; Mon, 28 Dec 2020 06:45:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726540AbgL1Goo (ORCPT ); Mon, 28 Dec 2020 01:44:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726336AbgL1Goo (ORCPT ); Mon, 28 Dec 2020 01:44:44 -0500 Received: from mail-oo1-xc36.google.com (mail-oo1-xc36.google.com [IPv6:2607:f8b0:4864:20::c36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 180FEC061794 for ; Sun, 27 Dec 2020 22:44:04 -0800 (PST) Received: by mail-oo1-xc36.google.com with SMTP id k7so2030089ooa.0 for ; Sun, 27 Dec 2020 22:44:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=o5wtPX61QoOqoZU2VTRJCE3ZyQ3KdZXG3FjCWYnhbEo=; b=MBH2w4ZV23RJuSVoaMPfo6ofBhwPb4jewXSeYQP1woVvN0xBSyjZWO4V96+cOKOtnL 3jCjNCOgv3I+YECgRSpVULJVXQhGZt1uchfOt8BAsCMtx4C+2cBR+qkrCkamned2He46 SERg4fDJusnUBrJhqRzLq8ROXsSy5J3dYE1Lsw33VAELTQKK/p2FE36yScc77AOXTzQb UfNXx60MJaNTev25LrjbWQPq5vj8uYXozn3xWo6THV0WcAAa5fYKiCU+eDYVV5mIs3d8 chsppqTQkqI/DyVSrSPfw3Hv8Mw3rI6rw4gj7SbSKMSIGfcGEaoiZtFuCKpEKFkFC+A+ i7vw== 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:in-reply-to:message-id :references:user-agent:mime-version; bh=o5wtPX61QoOqoZU2VTRJCE3ZyQ3KdZXG3FjCWYnhbEo=; b=OCFKcc+XZShpY7n0/mJRJuX8vmuE+WpAdysyEF6gIBxnagzLG54gDqhjwyGBwjR7AJ FMoeHhIIHzwTadJY5FmVXhOGhEZ7lRXFSfuhG4AqvSl8LTeEGB/GHXymULbnTFjd/m2Q RAm6NvsdSjfCaWYLEOs8CuAhk0f4lWdAFV8gbraJTkvpR3xtCxp6wnPiufNzDlqxAuaK 5i9jXlUJOS2oLEJGyxRSffIXSNVddLVDIZFRB5QuisypIBv86in39MnIsgaSXdNYajPR bpm/+Djp4z5K/tip917nxra10LMmrlrKQpEvSRxYUeX5sDxnezqpx7DfXjnebX9qAweb ynxA== X-Gm-Message-State: AOAM532eOD21HPWsm+hbbBznROTzeTg/c3bwuz/PLb4kSL7iZWlzcOo7 5rvH1nxPY8CAFm4N0tqr5zxpWQ== X-Google-Smtp-Source: ABdhPJxptFi0jlfOZ1KQ6ymnKZrDWvFuVR0GjxXiDxg91Uwd+ugMtO2uhXZ+YCY0rcz1P04NWG54nw== X-Received: by 2002:a4a:cb84:: with SMTP id y4mr29970687ooq.70.1609137842984; Sun, 27 Dec 2020 22:44:02 -0800 (PST) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id l134sm8666271oig.25.2020.12.27.22.44.01 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Sun, 27 Dec 2020 22:44:02 -0800 (PST) Date: Sun, 27 Dec 2020 22:43:44 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Linus Torvalds cc: "Kirill A. Shutemov" , Hugh Dickins , Matthew Wilcox , "Kirill A. Shutemov" , Will Deacon , Linux Kernel Mailing List , Linux-MM , Linux ARM , Catalin Marinas , Jan Kara , Minchan Kim , Andrew Morton , Vinayak Menon , Android Kernel Team Subject: Re: [PATCH 1/2] mm: Allow architectures to request 'old' entries when prefaulting In-Reply-To: Message-ID: References: <20201225113157.e7hmluffh56fszfc@box> <20201226204335.dikqkrkezqet6oqf@box> <20201226224016.dxjmordcfj75xgte@box> <20201227234853.5mjyxcybucts3kbq@box> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 27 Dec 2020, Linus Torvalds wrote: > On Sun, Dec 27, 2020 at 3:48 PM Kirill A. Shutemov wrote: > > > > I did what Hugh proposed and it got clear to my eyes. It gets somewhat > > large, but take a look. > > Ok, it's not that much bigger, and the end result is certainly much > clearer wrt locking. > > So that last version of yours with the fix for the uninitialized 'ret' > variable looks good to me. > > Of course, I've said that before, and have been wrong. So ... And guess what... it's broken. I folded it into testing rc1: segfault on cc1, systemd "Journal file corrupted, rotating", seen on more than one machine. I've backed it out, rc1 itself seems fine, I'll leave rc1 under load overnight, then come back to the faultaround patch tomorrow; won't glance at it tonight, but maybe Kirill will guess what's wrong. Hugh