Date: Wed, 23 May 2018 18:18:38 -0700 From: Eitan Adler <lists@eitanadler.com> To: "Jonathan T. Looney" <jtl@freebsd.org> Cc: Matthew Macy <mmacy@freebsd.org>, John Baldwin <jhb@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r334104 - in head/sys: netinet sys Message-ID: <CAF6rxgnP9B-40NPpTLE7KpvR03bcqXJcnCpkditYiAK%2B_besXA@mail.gmail.com> In-Reply-To: <CADrOrmtmSYtMt4vrqdFHrLqAArBaws8bAeynPa8X_sz7ui86uw@mail.gmail.com> References: <201805231700.w4NH05hs047395@repo.freebsd.org> <2281830.zrSQodBeDb@ralph.baldwin.cx> <CAPrugNo8_h5jnn2Yt250ZH1crwxHhK46QK1vfdyWssYjuuSAqQ@mail.gmail.com> <CADrOrmtmSYtMt4vrqdFHrLqAArBaws8bAeynPa8X_sz7ui86uw@mail.gmail.com>
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On 23 May 2018 at 17:40, Jonathan T. Looney <jtl@freebsd.org> wrote: > On Wed, May 23, 2018 at 7:13 PM, Matthew Macy <mmacy@freebsd.org> wrote: >> >> On Wed, May 23, 2018 at 11:52 AM, John Baldwin <jhb@freebsd.org> 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. +1 to M_ZERO_INVARIANTS -- Eitan Adler
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