svn commit: r333052 - head/sys/vm

Mateusz Guzik mjguzik at gmail.com
Fri Apr 27 14:35:46 UTC 2018


On Fri, Apr 27, 2018 at 4:29 PM, Rodney W. Grimes <
freebsd at pdx.rh.cn85.dnsmgr.net> wrote:

> [ Charset UTF-8 unsupported, converting... ]
> > Author: mjg
> > Date: Fri Apr 27 05:37:35 2018
> > New Revision: 333052
> > URL: https://svnweb.freebsd.org/changeset/base/333052
> >
> > Log:
> >   uma: whack main zone counter update in the slow path
>
> Remove might be a better word, whack is ambigous in this context.
>
>
Ok.


> >   Cached counters are typically zero at this point so it performs
> >   avoidable atomics. Everything reading them also reads the cached
> >   ones, thus there is really no point.
>
> No point in?  reading them, writting them, updating them?
>

No point in doing the update, hence the removal.


>
> >
> >   Reviewed by:                jeff
> >
> > Modified:
> >   head/sys/vm/uma_core.c
> >
> > Modified: head/sys/vm/uma_core.c
> > ============================================================
> ==================
> > --- head/sys/vm/uma_core.c    Fri Apr 27 05:36:02 2018        (r333051)
> > +++ head/sys/vm/uma_core.c    Fri Apr 27 05:37:35 2018        (r333052)
> > @@ -2329,14 +2329,6 @@ zalloc_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;
> > -
> >       /* See if we lost the race to fill the cache. */
> >       if (cache->uc_allocbucket != NULL) {
> >               ZONE_UNLOCK(zone);
> >
> >
>
> --
> Rod Grimes
> rgrimes at freebsd.org
>



-- 
Mateusz Guzik <mjguzik gmail.com>


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