On Sat 12-03-22 07:16:21, Wei Yang wrote: > When mz is not NULL, mem_cgroup_largest_soft_limit_node() has removed > it from rb_tree. > > Not necessary to call __mem_cgroup_remove_exceeded() again. Yes, the call seems to be unnecessary with the current code. mz can either come from mem_cgroup_largest_soft_limit_node or __mem_cgroup_largest_soft_limit_node both rely on the latter so the mz is always off the tree indeed. > Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> After the changelog is completed you can add Acked-by: Michal Hocko <mhocko@xxxxxxxx> In general, though, I am not a super fan of changes like these. The code works as expected, the call for __mem_cgroup_remove_exceeded will not really add much of an overhead and at least we can see that mz is always removed before it is re-added back. In a hot path I would care much more of course but this is effectivelly a dead code as the soft limit itself is mostly a relict of past. Please keep this in mind when you want to make further changes to this area. The review is not free of cost and I am not sure spending time on this area is worthwhile unless there is a real usecase in mind. Thanks! > --- > mm/memcontrol.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index f898320b678a..d70bf5cf04eb 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3458,7 +3458,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, > nr_reclaimed += reclaimed; > *total_scanned += nr_scanned; > spin_lock_irq(&mctz->lock); > - __mem_cgroup_remove_exceeded(mz, mctz); > > /* > * If we failed to reclaim anything from this memory cgroup > -- > 2.33.1 -- Michal Hocko SUSE Labs
