Re: [patch] oom: avoid killing kthreads if they assume the oom killed thread's mm

[Michal Hocko <mhocko@suse.cz>]

On Tue 26-07-11 15:05:23, David Rientjes wrote:
> On Tue, 26 Jul 2011, Michal Hocko wrote:
> 
> > > After selecting a task to kill, the oom killer iterates all processes and
> > > kills all other threads that share the same mm_struct in different thread
> > > groups.  It would not otherwise be helpful to kill a thread if its memory
> > > would not be subsequently freed.
> > > 
> > > A kernel thread, however, may assume a user thread's mm by using
> > > use_mm().  This is only temporary and should not result in sending a
> > > SIGKILL to that kthread.
> > 
> > Good catch. Have you ever seen this happening?
> > 
> 
> No, this is just another patch to make the kernel more use_mm()-friendly.  
> Before that capability was introduced, it was possible to assume that a 
> kthread would always have a NULL mm pointer, so it wasn't previously 
> required for this code.

OK

Thanks
-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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