Re: [RFC v1 13/14] rcu/kfree: Fix kfree_rcu_shrink_count() return value

[Joel Fernandes <joel@joelfernandes.org>]

On Fri, May 13, 2022 at 04:54:02PM +0200, Uladzislau Rezki wrote:
> On Thu, May 12, 2022 at 03:04:41AM +0000, Joel Fernandes (Google) wrote:
> > As per the comments in include/linux/shrinker.h, .count_objects callback
> > should return the number of freeable items, but if there are no objects
> > to free, SHRINK_EMPTY should be returned. The only time 0 is returned
> > should be when we are unable to determine the number of objects, or the
> > cache should be skipped for another reason.
> > 
> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > ---
> >  kernel/rcu/tree.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 3828ac3bf1c4..f191542cdf5e 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -3637,7 +3637,7 @@ kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
> >  		atomic_set(&krcp->backoff_page_cache_fill, 1);
> >  	}
> >  
> > -	return count;
> > +	return count == 0 ? SHRINK_EMPTY : count;
> >  }
> >  
> >  static unsigned long
> > -- 
> > 2.36.0.550.gb090851708-goog
> > 
> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

thanks!

 - Joel

> 
> --
> Uladzisalu Rezki