Re: [PATCH 08 of 11] anon-vma-rwsem

[Andrea Arcangeli <andrea@xxxxxxxxxxxx>]

On Wed, May 07, 2008 at 03:31:03PM -0700, Andrew Morton wrote:
> Nope.  We only need to take the global lock before taking *two or more* of
> the per-vma locks.
> 
> I really wish I'd thought of that.

I don't see how you can avoid taking the system-wide-global lock
before every single anon_vma->lock/i_mmap_lock out there without
mm_lock.

Please note, we can't allow a thread to be in the middle of
zap_page_range while mmu_notifier_register runs.

vmtruncate takes 1 single lock, the i_mmap_lock of the inode. Not more
than one lock and we've to still take the global-system-wide lock
_before_ this single i_mmap_lock and no other lock at all.

Please elaborate, thanks!

-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
Don't miss this year's exciting event. There's still time to save $100. 
Use priority code J8TL2D2. 
_______________________________________________
kvm-devel mailing list
kvm-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/kvm-devel