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

[Johannes Weiner]

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 :)