Re: [PATCH v3] mm: mglru: fix stale batch updates after memcg reparenting

[Qi Zheng <qi.zheng@linux.dev>]

On 6/26/26 5:39 PM, Johannes Weiner wrote:
> On Fri, Jun 26, 2026 at 03:04:17PM +0800, Qi Zheng wrote:
>> On 6/26/26 2:48 PM, Harry Yoo wrote:
>>> On 6/26/26 3:24 PM, Qi Zheng wrote:
>>>> On 6/26/26 12:59 PM, Harry Yoo wrote:
>>>>> Observing a dying cgroup should be rare anyway, it's worth focusing
>>>>> more on readability?
>>>>
>>>> While it's rare to encounter consecutive dying memcgs, it can still
>>>> happen, right?
>>>
>>> But is worth saving a few instruction in a basic block that is
>>> unlikely() to be executed?
>>
>> I don't have a strong opinion here. Hi Johannes, I'll leave the decision
>> up to you. If necessary, I can send out the v4.
> 
> Yes, I was thinking what Harry actually bothered to spell out ;)
> 
> The race is rare, multiple levels even rarer, and even *then*
> mem_cgroup_lruvec() is a quick inline.
> 
> This way you have one block to handle that one rare race
> condition. One place to put the comment. No labels, no goto.
> 
> Simplicity wins :)

Okay, I will update it as you suggested and send out the v4.

Hi Shakeel, do we really need to move lock_batch_lruvec() to
memcontrol.h? It's currently only used by reset_batch_size().

Thanks,
Qi