Messages in this thread | | | Date | Thu, 8 May 2008 00:44:06 +0200 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 08 of 11] anon-vma-rwsem |
| |
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!
| |