On Fri, Apr 04, 2008 at 04:12:42PM -0700, Jeremy Fitzhardinge wrote: > I think you can break this if() down a bit: > > if (!(vma->vm_file && vma->vm_file->f_mapping)) > continue;
It makes no difference at runtime, coding style preferences are quite subjective. > So this is an O(n^2) algorithm to take the i_mmap_locks from low to high > order? A comment would be nice. And O(n^2)? Ouch. How often is it > called? It's called a single time when the mmu notifier is registered. It's a very slow path of course. Any other approach to reduce the complexity would require memory allocations and it would require mmu_notifier_register to return -ENOMEM failure. It didn't seem worth it. > And is it necessary to mush lock and unlock together? Unlock ordering > doesn't matter, so you should just be able to have a much simpler loop, no? That avoids duplicating .text. Originally they were separated. unlock can't be a simpler loop because I didn't reserve vm_flags bitflags to do a single O(N) loop for unlock. If you do malloc+fork+munmap two vmas will point to the same anon-vma lock, that's why the unlock isn't simpler unless I mark what I locked with a vm_flags bitflag. ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Register now and save $200. Hurry, offer ends at 11:59 p.m., Monday, April 7! Use priority code J8TLD2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
