Re: [patch v3] mm, oom: fix unnecessary killing of additional processes

[Michal Hocko]

On Fri 06-07-18 17:05:39, David Rientjes wrote:
[...]
> Blockable mmu notifiers and mlocked memory is not the extent of the 
> problem, if a process has a lot of virtual memory we must wait until 
> free_pgtables() completes in exit_mmap() to prevent unnecessary oom 
> killing.  For implementations such as tcmalloc, which does not release 
> virtual memory, this is important because, well, it releases this only at 
> exit_mmap().  Of course we cannot do that with only the protection of 
> mm->mmap_sem for read.

And how exactly a timeout helps to prevent from "unnecessary killing" in
that case?
-- 
Michal Hocko
SUSE Labs