Re: [patch 3/3] mm: fault handler to replace nopage and populate

Benjamin Herrenschmidt
2006-10-09T20:46:00Z

> Wouldn't that confuse concurrent readers?
>
> Could it be an option to make it safe for the fault handler to
> temporarily drop the mmap_sem read lock given that some conditions TBD
> are met?
> In that case it can retake the mmap_sem write lock, do the VMA flags
> modifications, downgrade and do the pte modifications using a helper, or
> even use remap_pfn_range() during the time the write lock is held?

If we return NOPAGE_REFAULT, then yes, we can drop the mmap sem, though
I 'm not sure we need that...

Ben.