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SubjectRe: [RFC] oom-kill: give the dying task a higher priority
On Wed, Jun 02, 2010 at 10:54:01PM +0900, 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.

Ok, that was not a good idea after all :)

But I understand the !rt_task(p) test is necessary to avoid decrementing
the priority of an eventual RT task selected to die. Though it may also be
a corner case in badness().

Luis
--
[ Luis Claudio R. Goncalves Bass - Gospel - RT ]
[ Fingerprint: 4FDD B8C4 3C59 34BD 8BE9 2696 7203 D980 A448 C8F8 ]



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