Re: [PATCH 1/1] mm/thp: clear deferred split shrinker bits when queues drain

[David Hildenbrand (Arm)]

On 6/2/26 14:47, Lance Yang wrote:
> 
> 
> On 2026/6/2 20:11, David Hildenbrand (Arm) wrote:
>> On 6/2/26 06:38, Lance Yang wrote:
>>> Sorry, I missed Johannes in Cc ...
>>>
>>
>> What's the effect of that? Would we consider it a fix that we'd want to backport?
> 
> Just a stale memcg shrinker bit :) I'd treat this patch as a small
> cleanup.
> 
> Once the queue is empty, count_objects() returns 0. That skips the scan,
> but shrink_slab_memcg() only clears the bit on SHRINK_EMPTY, not 0.
> 
> So memcg reclaim can keep calling the shrinker even though there is
> nothing on that queue.
> 
>>>
>>
>> This is against Johannes' work, right?
> 
> Yep, I noticed it there, but the behavior is older.
> 
>> If this is a fix, likely it would be fixing 87eaceb3faa5 ("mm: thp: make
>> deferred split shrinker memcg aware"), right?
> 
> No missed reclaim, just some extra reclaim work :)

Thanks for clarifying! :)

Reviewed-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>

-- 
Cheers,

David