Messages in this thread |  | | | Date | Fri, 04 Jan 2008 13:07:11 -0500 | | From | Larry Woodman <> | | Subject | Re: [patch 00/19] VM pageout scalability improvements |
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Rik van Riel wrote:
>On Fri, 04 Jan 2008 17:34:00 +0100 >Andi Kleen <andi@firstfloor.org> wrote: > > >>Lee Schermerhorn <Lee.Schermerhorn@hp.com> writes: >> >> >> >>>We can easily [he says, glibly] reproduce the hang on the anon_vma lock >>> >>> >>Is that a NUMA platform? On non x86? Perhaps you just need queued spinlocks? >> >> > >I really think that the anon_vma and i_mmap_lock spinlock hangs are >due to the lack of queued spinlocks. Not because I have seen your >system hang, but because I've seen one of Larry's test systems here >hang in scary/amusing ways :) > Changing the anon_vma->lock into a rwlock_t helps because page_lock_anon_vma() can take it for read and thats where the contention is. However its the fact that under some tests, most of the pages are in vmas queued to one anon_vma that causes so much lock contention.
> >With queued spinlocks the system should just slow down, not hang. > > >
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