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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9898C433EF for ; Tue, 18 Jan 2022 16:34:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D40676B0071; Tue, 18 Jan 2022 11:34:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CEF466B0072; Tue, 18 Jan 2022 11:34:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BB66A6B0073; Tue, 18 Jan 2022 11:34:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id A97C86B0071 for ; Tue, 18 Jan 2022 11:34:20 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3A98595180 for ; Tue, 18 Jan 2022 16:34:20 +0000 (UTC) X-FDA: 79043955480.22.30F890F Received: from mail-yb1-f177.google.com (mail-yb1-f177.google.com [209.85.219.177]) by imf24.hostedemail.com (Postfix) with ESMTP id B5FCA18000D for ; Tue, 18 Jan 2022 16:34:19 +0000 (UTC) Received: by mail-yb1-f177.google.com with SMTP id c10so57691055ybb.2 for ; Tue, 18 Jan 2022 08:34:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=cFLJZnNfVA2hCXwB0s6ZjiPuvxnZUePWAooBTPU852M=; b=G5erIZGbvmegUtG5C0zxO4yXCWE4gtDIbjk3ToPHrs+DaC2xKf7n/9Rij7MZA7wqyW DkGv6kljPu7+YqY8zLxf5FUc9+It3uU5r2ctlM5ZhKw21mPd2XcPP4EngAJXVY2YGVx9 kuA7xwKFhP+L/HduNMi335CM2fipZBVcGMcvwA/fzAnl5srEPtmseEpLI+hf6KicC55c iESC+oJUiVUcJC55eSHcJvaY7B1T9YwPMp/VTMFydv8nRyfOjMC5C3/UIa60aqR9CyDE BPnxBRf+Wj9OzVVgHDhNw3VQfz7D/aygtcHplEvdZuTnzugy4/vceEn4oCFf/mKLvP0n aMew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=cFLJZnNfVA2hCXwB0s6ZjiPuvxnZUePWAooBTPU852M=; b=48UKEbgEJzBItJDRtYbWFtYeB+JKbNXbxPMTYtCMzoxyzpJvnFjx8TfJlCQaXeftMB xaN6iX0LaK/C8hycKNlY6k5EbVE+mFN+STX0ZSozy+NAv6+JfQVPSO8gw4Jtb1n5InAF DgoEYxJXRvFrKc7Pgl5c0QngkwhAx9no4/3es+986Qz6hFHy9XT2neo3fLibq6/Z8OZG jwf0K40ltUhqOU5q/Z7RRSD2zmEWN7pIOm9nE6/rWwW3Zf0Ye/NJmt8Ks9icOEZyjWS8 UsFkTSkNmYD6yZJNkHWGesvCymWxXyDfl3ztlPOGqy/pxT8kCh/rJ3QJf+TrCxB/2vRl F0RQ== X-Gm-Message-State: AOAM532rvmVZpyXYuSEwaEFSsLzbH+aEM7auKxmaI3Yo5Ksg4/HDxQMC DOvlU4Yo9ZfOTZlD1eDkIp9c94uqBbfcf0w8YyJHfw== X-Google-Smtp-Source: ABdhPJzIWXCdR/TtXqi3JjuZe2JymY69Sm90gPsH4SEWVht4RaZfi/F9gSRFFK1+L6+w1N12qFQMrcIMl9PaDOrq3Zg= X-Received: by 2002:a25:3791:: with SMTP id e139mr1806490yba.488.1642523658728; Tue, 18 Jan 2022 08:34:18 -0800 (PST) MIME-Version: 1.0 References: <20220114140222.6b14f0061194d3200000c52d@linux-foundation.org> <20220114220555.kAbhSEmus%akpm@linux-foundation.org> In-Reply-To: From: Suren Baghdasaryan Date: Tue, 18 Jan 2022 08:34:08 -0800 Message-ID: Subject: Re: [patch 056/146] mm: rearrange madvise code to allow for reuse To: Linus Torvalds Cc: Andrew Morton , Colin Cross , Dave Hansen , "Eric W. Biederman" , Cyrill Gorcunov , Johannes Weiner , Hugh Dickins , Jan Glauber , John Stultz , Kees Cook , Linux-MM , Mel Gorman , Minchan Kim , Ingo Molnar , mm-commits@vger.kernel.org, Oleg Nesterov , Pekka Enberg , Peter Zijlstra , David Rientjes , Rob Landley , "Serge E. Hallyn" , Shaohua Li , Al Viro Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: B5FCA18000D X-Stat-Signature: 83qymp9ywr9588r3qe9y3wu8x5fdmqp7 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=G5erIZGb; spf=pass (imf24.hostedemail.com: domain of surenb@google.com designates 209.85.219.177 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam07 X-HE-Tag: 1642523659-224775 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Jan 15, 2022 at 6:16 AM Linus Torvalds wrote: > > On Sat, Jan 15, 2022 at 12:06 AM Andrew Morton > wrote: > > > > Speed up fork() by up to 40% by refcounting the anon vma name field. > > What? > > No. > > This doesn't speed up anything at all. > > The refcounting of the anon-vma name field avoids a 40% regression > that comes from adding the field in the first place, but this commit > message makes it sound like this series is speeding up fork() by 40%. > > I don't mind the series, but I absolutely mind these kinds of horribly > misleading commit messages. > > This is literally the first commit in the series - and the series in > no way improves performance by 40% in the end, it just first makes it > worse, and then fixes the regression. > > I can speed up any function by a thousand percent - if I'm just > allowed to make it horribly slow first, and only count the final > speedup win when I remove the overhead of the garbage I added. Thanks for fixing it! I see in your tree it is changed to: "Avoid performance regression of the new anon vma name field refcounting it." Please let me know if anything else is left to be done here. > > Linus