Messages in this thread | | | Date | Wed, 2 Jun 2010 14:11:47 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [RFC] oom-kill: give the dying task a higher priority |
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On Wed, 2 Jun 2010, KOSAKI Motohiro wrote:
> > > @@ -291,9 +309,10 @@ static struct task_struct *select_bad_process(unsigned long *ppoints, > > > * Otherwise we could get an easy OOM deadlock. > > > */ > > > if (p->flags & PF_EXITING) { > > > - if (p != current) > > > + if (p != current) { > > > + boost_dying_task_prio(p, mem); > > > return ERR_PTR(-1UL); > > > - > > > + } > > > chosen = p; > > > *ppoints = ULONG_MAX; > > > } > > > > This has the potential to actually make it harder to free memory if p is > > waiting to acquire a writelock on mm->mmap_sem in the exit path while the > > thread holding mm->mmap_sem is trying to run. > > if p is waiting, changing prio have no effect. It continue tol wait to release mmap_sem. >
And that can reduce the runtime of the thread holding a writelock on mm->mmap_sem, making the exit actually take longer than without the patch if its priority is significantly higher, especially on smaller machines.
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