From owner-svn-src-head@freebsd.org Thu May 24 00:40:46 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 03B27EEEE8B; Thu, 24 May 2018 00:40:46 +0000 (UTC) (envelope-from jonlooney@gmail.com) Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 81543878B5; Thu, 24 May 2018 00:40:45 +0000 (UTC) (envelope-from jonlooney@gmail.com) Received: by mail-wm0-f44.google.com with SMTP id w194-v6so399399wmf.2; Wed, 23 May 2018 17:40:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=wxl4fsD/YDHIPKLTMtftqDBw+z7cjFaFjc9i369FEZQ=; b=GB4593g9hTNRyjdhmKL1NTKwBm3PeqTch3z8E9LVxiTUeeoyQ+BU1c8OOJbdv5WFjp rCqm/iM5NbXec7sG1/YghDLqScuDm3lQE2LF7VfO9ZuER/jHP4ShL79wOTUjrxtgrqXx g1EHMaF+HXr0MgBOqelWV14hbx0SbAfoVk8zLYK1dvLkFmLq3DG/mh2IoFZT9LW1NmZQ XirYEu1ZR0ksO5eaBGkT6xK4KfK7JvcvMYNuhayZmiyZJTh14Yc/HO0dnxwqtnXY6SzJ bK6EiN2EDxwbuCceu+2eYPQrVhOw3JM2ezLhf35wDBBPWJv8YK3f8VD06kd6sCo0FoCK oZkQ== X-Gm-Message-State: ALKqPwepCRAlROKMNmMI/2EJjylmh4fvyBaQu3qsi3xHAWBnZfGfQ+34 /+KtMgDEFU/pJLWjKP5gO8I0ASAE X-Google-Smtp-Source: AB8JxZovX1hTshcNAgHLDlR9XNIjH2C5N2iej6G03sXFZuowDpiLNlooy2ptESsfO/hZJWLnnr34wg== X-Received: by 2002:a50:921c:: with SMTP id i28-v6mr9333761eda.27.1527122438405; Wed, 23 May 2018 17:40:38 -0700 (PDT) Received: from mail-wm0-f54.google.com (mail-wm0-f54.google.com. [74.125.82.54]) by smtp.gmail.com with ESMTPSA id g11-v6sm10917175edg.64.2018.05.23.17.40.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 May 2018 17:40:38 -0700 (PDT) Received: by mail-wm0-f54.google.com with SMTP id q4-v6so5331580wmq.1; Wed, 23 May 2018 17:40:37 -0700 (PDT) X-Received: by 2002:a1c:170f:: with SMTP id 15-v6mr5662726wmx.90.1527122437786; Wed, 23 May 2018 17:40:37 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:adf:c504:0:0:0:0:0 with HTTP; Wed, 23 May 2018 17:40:37 -0700 (PDT) In-Reply-To: References: <201805231700.w4NH05hs047395@repo.freebsd.org> <2281830.zrSQodBeDb@ralph.baldwin.cx> From: "Jonathan T. Looney" Date: Wed, 23 May 2018 20:40:37 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: svn commit: r334104 - in head/sys: netinet sys To: Matthew Macy Cc: John Baldwin , src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.26 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2018 00:40:46 -0000 On Wed, May 23, 2018 at 7:13 PM, Matthew Macy wrote: > > On Wed, May 23, 2018 at 11:52 AM, John Baldwin wrote: > > On Wednesday, May 23, 2018 05:00:05 PM Matt Macy wrote: > >> Author: mmacy > >> Date: Wed May 23 17:00:05 2018 > >> New Revision: 334104 > >> URL: https://svnweb.freebsd.org/changeset/base/334104 > >> > >> Log: > >> epoch: allow for conditionally asserting that the epoch context fields > >> are unused by zeroing on INVARIANTS builds > > > > Is M_ZERO really so bad that you need to make it conditional? > > In this case not at all. It's only exercised by sysctl handlers. I'm > mostly responding to an inquiry by jtl. However, gratuitous M_ZERO > usage does have a cumulative adverse performance impact. I appreciate you making this change. And, I do think it is worth avoiding M_ZERO where it is unnecessary, for the reason you state. > > I would probably have preferred something like 'M_ZERO_INVARIANTS' > > instead perhaps (or M_ZERO_EPOCH) that only controls M_ZERO and is > > still or'd with M_WAITOK or M_NOWAIT. > > Yes. I like that better too. Thanks. Yes, that does seem better. Thanks! Jonathan