svn commit: r336231 - head/sys/vm

[Mateusz Guzik]

uma_zone_get_cur iterates the per-cpu stats and looks at the zone-global
stats. The patch only gets rid of rolling them up, thus there is no
difference from the pov of this func.
I don't follow the remark about uma_reclaim.

On Fri, Jul 13, 2018 at 12:58 AM, Mark Johnston <markj at freebsd.org> wrote:

> On Thu, Jul 12, 2018 at 10:35:52PM +0000, Mateusz Guzik wrote:
> > Author: mjg
> > Date: Thu Jul 12 22:35:52 2018
> > New Revision: 336231
> > URL: https://svnweb.freebsd.org/changeset/base/336231
> >
> > Log:
> >   uma: whack main zone counter update in the slow path, freeing side
> >
> >   See r333052.
> >
> > Modified:
> >   head/sys/vm/uma_core.c
> >
> > Modified: head/sys/vm/uma_core.c
> > ============================================================
> ==================
> > --- head/sys/vm/uma_core.c    Thu Jul 12 22:34:40 2018        (r336230)
> > +++ head/sys/vm/uma_core.c    Thu Jul 12 22:35:52 2018        (r336231)
> > @@ -3135,14 +3135,6 @@ zfree_start:
> >       cpu = curcpu;
> >       cache = &zone->uz_cpu[cpu];
> >
> > -     /*
> > -      * Since we have locked the zone we may as well send back our
> stats.
> > -      */
> > -     atomic_add_long(&zone->uz_allocs, cache->uc_allocs);
> > -     atomic_add_long(&zone->uz_frees, cache->uc_frees);
> > -     cache->uc_allocs = 0;
> > -     cache->uc_frees = 0;
> > -
>
> Doesn't this break the accounting of these stats?  uma_reclaim() doesn't
> update them when it frees cached items, and uma_zone_get_cur() doesn't
> look at the stats for cached buckets.
>



-- 
Mateusz Guzik <mjguzik gmail.com>