Re: [RFC PATCH] mm, oom: allow oom reaper to race with exit_mmap

[Michal Hocko]

On Tue 27-06-17 20:39:28, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > > I wonder why you prefer timeout based approach. Your patch will after all
> > > set MMF_OOM_SKIP if operations between down_write() and up_write() took
> > > more than one second.
> > 
> > if we reach down_write then we have unmapped the address space in
> > exit_mmap and oom reaper cannot do much more.
> 
> So, by the time down_write() is called, majority of memory is already released, isn't it?

In most cases yes. To be put it in other words. By the time exit_mmap
takes down_write there is nothing more oom reaper could reclaim.

-- 
Michal Hocko
SUSE Labs