svn commit: r258336 - head/sys/vm

[Alexander Motin]

On 19.11.2013 14:12, Gleb Smirnoff wrote:
> On Tue, Nov 19, 2013 at 04:11:09PM +0400, Gleb Smirnoff wrote:
> T>   Alexander,
> T>
> T> On Tue, Nov 19, 2013 at 10:05:53AM +0000, Alexander Motin wrote:
> T> A> Author: mav
> T> A> Date: Tue Nov 19 10:05:53 2013
> T> A> New Revision: 258336
> T> A> URL: http://svnweb.freebsd.org/changeset/base/258336
> T> A>
> T> A> Log:
> T> A>   Implement soft pressure on UMA cache bucket sizes.
> T> A>
> T> A>   Every time system detects low memory condition decrease bucket sizes for
> T> A>   each zone by one item.  As result, higher memory pressure will push to
> T> A>   smaller bucket sizes and so smaller per-CPU caches and so more efficient
> T> A>   memory use.
> T> A>
> T> A>   Before this change there was no force to oppose buckets growth as result
> T> A>   of practically inevitable zone lock conflicts, and after some run time
> T> A>   per-CPU caches could consume enough RAM to kill the system.
> T>
> T> Brief review of patch tells me that system never recovers from this. uz_count
> T> it decremented only and never incremented.

You are wrong.  uz_count is incremented in uma_zalloc_arg() same as it 
was always before. Probably it was too brief review. :)

> Do I understand right that r258338 fixes that?

Not fixes (since there was no bug), but adds second increment point.

-- 
Alexander Motin