From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>,
Giangiacomo Mariotti <gg.mariotti@gmail.com>,
Bill Davidsen <davidsen@tmr.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
x86 maintainers <x86@kernel.org>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: Possible bug in 2.6.34 slub
Date: Thu, 3 Jun 2010 09:51:41 +0300 [thread overview]
Message-ID: <AANLkTinxOJShwd7xUornVI89BmJnbX9-a7LVWaciNdr5@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1006011445100.9438@router.home>
On Tue, Jun 1, 2010 at 10:48 PM, Christoph Lameter
<cl@linux-foundation.org> wrote:
> On Tue, 1 Jun 2010, Randy Dunlap wrote:
>
>> > >>> My cpu is an I7 920, so it has 4 cores and there's hyperthreading
>> > >>> enabled, so there are 8 logical cpus. Is this a bug?
>
> Yes its a bug in the arch code or BIOS. The system configuration tells us
> that there are more possible cpus and therefore the system prepares for
> the additional cpus to be activated at some later time.
I guess we should CC x86 maintainers then!
>> Sorry, I think that I misread your report.
>> It does look like misinformation.
>> Let's cc Christoph Lameter & Pekka.
>>
>>
>> > The point is, I guess(didn't actually look at the code), if that's
>> > just the count of MAX number of cpus supported, which is a config time
>> > define and then the actual count gets refined afterwards by slub
>> > too(because I know that the rest of the kernel knows I've got 4
>> > cores/8 logical cpus) or not. Is that it? If this is not the case(that
>> > is, it's not a static define used as a MAX value), then I can't see
>> > what kind of boot/init time info it is. If it's a boot-time info, it
>> > just means it's a _wrong_ boot-time info.
>
> No that is the max nr of cpus possible on this machine. The count is
> determined by hardware capabilities on bootup. If they are not detected
> in the right way then you have the erroneous display (and the system
> configures useless per cpu structures to support nonexistent cpus).
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next prev parent reply other threads:[~2010-06-03 6:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AANLkTimEFy6VM3InWlqhVooQjKGSD3yBxlgeRbQC2r1L@mail.gmail.com>
[not found] ` <20100531165528.35a323fb.rdunlap@xenotime.net>
[not found] ` <4C047CF9.9000804@tmr.com>
[not found] ` <AANLkTilLq-hn59CBcLnOsnT37ZizQR6MrZX6btKPhfpb@mail.gmail.com>
2010-06-01 19:39 ` Possible bug in 2.6.34 slub Randy Dunlap
2010-06-01 19:48 ` Christoph Lameter
2010-06-01 21:11 ` Giangiacomo Mariotti
2010-06-01 21:27 ` Christoph Lameter
2010-06-03 6:51 ` Pekka Enberg [this message]
2010-06-03 13:34 ` Christoph Lameter
2010-06-04 18:39 ` Giangiacomo Mariotti
2010-06-07 22:35 ` Christoph Lameter
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