From owner-svn-src-all@freebsd.org Wed May 23 23:13:46 2018 Return-Path: Delivered-To: svn-src-all@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 D60A2EEBEAB; Wed, 23 May 2018 23:13:46 +0000 (UTC) (envelope-from mmacy@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8480B841F5; Wed, 23 May 2018 23:13:46 +0000 (UTC) (envelope-from mmacy@freebsd.org) Received: from mail-it0-f41.google.com (mail-it0-f41.google.com [209.85.214.41]) (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)) (Authenticated sender: mmacy) by smtp.freebsd.org (Postfix) with ESMTPSA id 4B912BBC2; Wed, 23 May 2018 23:13:46 +0000 (UTC) (envelope-from mmacy@freebsd.org) Received: by mail-it0-f41.google.com with SMTP id d10-v6so66079itj.1; Wed, 23 May 2018 16:13:46 -0700 (PDT) X-Gm-Message-State: ALKqPwffuAdAmSYsbkx8Dv3KM6ExXR+pzTMX5Lt0Y4bzotcE8/zMYkAq DUFYUstq8nC5NywAkQWLQUl0qVXQkaSuAigRqbA= X-Google-Smtp-Source: AB8JxZpy53l2AUtJ3BdGJiICY1MHUn2xekVxKocFe93Lnnts5WXb6mWTxcELxh0cn1a1bHNaVAieGo/yBAyO31y9uQk= X-Received: by 2002:a24:5b54:: with SMTP id g81-v6mr6986426itb.7.1527117225840; Wed, 23 May 2018 16:13:45 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:85ca:0:0:0:0:0 with HTTP; Wed, 23 May 2018 16:13:45 -0700 (PDT) In-Reply-To: <2281830.zrSQodBeDb@ralph.baldwin.cx> References: <201805231700.w4NH05hs047395@repo.freebsd.org> <2281830.zrSQodBeDb@ralph.baldwin.cx> From: Matthew Macy Date: Wed, 23 May 2018 16:13:45 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: svn commit: r334104 - in head/sys: netinet sys To: John Baldwin Cc: src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 May 2018 23:13:47 -0000 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 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. -M