Date: Mon, 26 Aug 2019 09:25:11 -0700 From: John Baldwin <jhb@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com>, Conrad Meyer <cem@freebsd.org> Cc: 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: <1a09a4ef-45aa-1bb2-5b16-1bde24df0f3d@FreeBSD.org> In-Reply-To: <20190824204353.GH71821@kib.kiev.ua> 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>
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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. -- John Baldwin
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