Re: [PATCH v7 2/2] mm/oom_kill: The OOM reaper traverses the VMA maple tree in reverse order

[Liam R. Howlett]

* Michal Hocko <mhocko@xxxxxxxx> [250904 08:21]:
> On Wed 03-09-25 15:02:34, Liam R. Howlett wrote:
> > * Michal Hocko <mhocko@xxxxxxxx> [250903 08:58]:
> > > On Wed 03-09-25 17:27:29, zhongjinji wrote:
> [...]
> > mmu_notifier_release(mm) is called early in the exit_mmap() path should
> > cause the mmu notifiers to be non-blocking (according to the comment in
> > v6.0 source of exit_mmap [1].
> 
> I am not sure I follow you here. How does this relate to the actual
> direction of the address space freeing?

It doesn't relate to the direction of the address freeing, I think it
explains the perf data a bit.

The exit_mmap() would have a decrease in mmu related work while this
thread will have an increase, I think.

If they race, this thread gets virtually nothing while exit does all of
the work.  If they don't race then the work is split.

Does that make sense?

Thanks,
Liam