svn commit: r289279 - in head/sys: kern vm

[Bryan Drewery]

On 10/29/2015 1:31 PM, Eric van Gyzen wrote:
> On 10/29/2015 15:25, Tijl Coosemans wrote:
>> On Wed, 14 Oct 2015 02:10:07 +0000 (UTC) Jeff Roberson <jeff at FreeBSD.org> wrote:
>>> Author: jeff
>>> Date: Wed Oct 14 02:10:07 2015
>>> New Revision: 289279
>>> URL: https://svnweb.freebsd.org/changeset/base/289279
>>>
>>> Log:
>>>   Parallelize the buffer cache and rewrite getnewbuf().  This results in a
>>>   8x performance improvement in a micro benchmark on a 4 socket machine.
>>>   
>>>    - Get buffer headers from a per-cpu uma cache that sits in from of the
>>>      free queue.
>>>    - Use a per-cpu quantum cache in vmem to eliminate contention for kva.
>>>    - Use multiple clean queues according to buffer cache size to eliminate
>>>      clean queue lock contention.
>>>    - Introduce a bufspace daemon that attempts to prevent getnewbuf() callers
>>>      from blocking or doing direct recycling.
>>>    - Close some bufspace allocation races that could lead to endless
>>>      recycling.
>>>    - Further the transition to a more modern style of small functions grouped
>>>      by prefix in order to improve growing complexity.
>>
>> I have an i386 system that locks up easily after this commit.  Booting
>> into single user and running make installkernel triggers it consistently.
> 
> I can't help you debug this, but I noticed a follow-up commit that fixed
> an uninitialized pointer introduced by this commit:
> 
> 	https://svnweb.freebsd.org/changeset/base/290155
> 
> Pending comments from more enlightened folk, you might try updating to
> that rev (if you can do so without a lockup...).

I didn't analyze it enough to know if my change was fixing an actual bug
and in what case. I think if so it is more likely to have random panics
then a consistent lock up though.


-- 
Regards,
Bryan Drewery


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