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Date:      Wed, 14 Aug 2013 09:21:45 -0700
From:      Jim Harris <jim.harris@gmail.com>
To:        Jeff Roberson <jroberson@jroberson.net>
Cc:        Alan Cox <alc@freebsd.org>, Attilio Rao <attilio@freebsd.org>, FreeBSD current <freebsd-current@freebsd.org>, Konstantin Belousov <kib@freebsd.org>, Colin Percival <cperciva@freebsd.org>
Subject:   Re: panic: UMA: Increase vm.boot_pages with 32 CPUs
Message-ID:  <CAJP=Hc9aOp58LUJFY8ZNGgm-pqDWj3LrgzU-2yBdznCGwUQ9zw@mail.gmail.com>
In-Reply-To: <alpine.BSF.2.00.1308131747050.4083@desktop>
References:  <5208A488.2050603@freebsd.org> <alpine.BSF.2.00.1308131203350.4083@desktop> <CAJP=Hc9KZfD-uKkOM%2BO=oAHiGj3vNwRa-fMgtKWEacOKL110DQ@mail.gmail.com> <alpine.BSF.2.00.1308131747050.4083@desktop>

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On Tue, Aug 13, 2013 at 8:47 PM, Jeff Roberson <jroberson@jroberson.net>wrote:

> On Tue, 13 Aug 2013, Jim Harris wrote:
>
>
>>
>>
>> On Tue, Aug 13, 2013 at 3:05 PM, Jeff Roberson <jroberson@jroberson.net>
>> wrote:
>>
>> It's not any one commit really, just creeping demand for more pages
>> before the VM can get started.  I would suggest making boot pages
>> scale with MAXCPU.  Or just raising it as the panic suggests.  We
>> could rewrite the way that the vm gets these early pages but it's a
>> lot of work and typically people just bump it and forget about it.
>>
>>
>> I ran into this problem today when enabling hyperthreading on my
>> dual-socket
>> Xeon E5 system.
>>
>> It looks like r254025 is actually the culprit.  Specifically, the new
>> mallocinit()/kmeminit() now invoke the new vmem_init() before
>> uma_startup2(), which allocates 16 zones out of the boot pages if I am
>> reading this correctly.  This is all done before uma_startup2() is called,
>> triggering the panic.
>>
>>
> I just disabled the quantum caches in vmem which allocate those 16 zones.
> This may alleviate the problem for now.
>
> Thanks,
> Jeff
>
>
Yes - this does alleviate the problem.  Thanks!

-Jim



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