Date: Mon, 26 Aug 2019 19:34:39 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@FreeBSD.org> Cc: Conrad Meyer <cem@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r351456 - head/sys/amd64/amd64 Message-ID: <20190826163439.GS71821@kib.kiev.ua> In-Reply-To: <1a09a4ef-45aa-1bb2-5b16-1bde24df0f3d@FreeBSD.org> References: <201908241528.x7OFSemm026182@repo.freebsd.org> <CAG6CVpWN56eRRUgCubK3F750zoDun8ZocLaot5w0H4Emrq9=xQ@mail.gmail.com> <20190824161503.GA71821@kib.kiev.ua> <CAG6CVpWMquckqAx7jQTam5qjB3GubrrzQYxnZafjwjLEjqf6Qg@mail.gmail.com> <20190824204353.GH71821@kib.kiev.ua> <1a09a4ef-45aa-1bb2-5b16-1bde24df0f3d@FreeBSD.org>
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On Mon, Aug 26, 2019 at 09:25:11AM -0700, John Baldwin wrote: > On 8/24/19 1:43 PM, Konstantin Belousov wrote: > > On Sat, Aug 24, 2019 at 11:47:52AM -0700, Conrad Meyer wrote: > >> On Sat, Aug 24, 2019 at 9:15 AM Konstantin Belousov <kostikbel@gmail.com> wrote: > >>> > >>> On Sat, Aug 24, 2019 at 08:49:42AM -0700, Conrad Meyer wrote: > >>>> Hi Konstantin, > >>>> > >>>> What is the motivation for this change? The commit message doesn't > >>>> really describe why it was done. > >>> > >>> Really it does. There is no point to request allocations for e.g. > >>> doublefault stack to be at the local domain, because this stack is only > >>> used once. Doublefault is definitely a machine halt situation, it does > >>> not matter if it generates inter-socket traffic to handle. > >>> > >>> Same for boot stacks, and for mce. > >>> > >>> The change avoids unnecessary constraints. > >> > >> Sure, but what is the harm of the unnecessary constraints? Does this > >> change fix an actual bug, or is it just a stylistic preference to > >> avoid domain-specific allocations for infrequently used objects? > > I am not sure about this being a stylistic preference. We usually > > write code to express the required actions. I removed constraints > > which did not added anything neither to code correctness nor to the > > performance. > > Judging by the thread on current though, this fixes boot panics on > machines with NUMA but CPUs that don't have local memory, correct? > I think that's the thing Conrad is asking. > This was discovered later.
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