On Mon, Jun 27, 2022 at 02:43:59PM -0700, Paul E. McKenney wrote: > On Mon, Jun 27, 2022 at 09:18:13PM +0000, Joel Fernandes wrote: > > On Mon, Jun 27, 2022 at 01:59:07PM -0700, Paul E. McKenney wrote: > > > On Mon, Jun 27, 2022 at 08:56:43PM +0200, Uladzislau Rezki 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@xxxxxxxxxxxxxxxxx> > > > > > --- > > > > > 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 711679d10cbb..935788e8d2d7 100644 > > > > > --- a/kernel/rcu/tree.c > > > > > +++ b/kernel/rcu/tree.c > > > > > @@ -3722,7 +3722,7 @@ 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 > > > > > -- > > > > > 2.37.0.rc0.104.g0611611a94-goog > > > > > > > > > Looks good to me! > > > > > > > > Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> > > > > > > Now that you mention it, this does look independent of the rest of > > > the series. I have pulled it in with Uladzislau's Reviewed-by. > > > > Thanks Paul and Vlad! > > > > Paul, apologies for being quiet. I have been working on the series and the > > review comments carefully. I appreciate your help with this work. > > Not a problem. After all, this stuff is changing some of the trickier > parts of RCU. We must therefore assume that some significant time and > effort will be required to get it right. To your point about trickier parts of RCU, the v2 series though I tested it before submitting is now giving me strange results with rcuscale. Sometimes laziness does not seem to be in effect (as pointed out by rcuscale), other times I am seeing stalls. So I have to carefully look through all of this again. I am not sure why I was not seeing these issues with the exact same code before (frustrated). thanks, - Joel
