Rik van Riel wrote:
On Fri, 04 Jan 2008 17:34:00 +0100
Andi Kleen <[EMAIL PROTECTED]> wrote:
Lee Schermerhorn <[EMAIL PROTECTED]> 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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