On Mon, 7 Apr 2008, Andrea Arcangeli wrote: > > > My mm_lock solution makes all rcu serialization an unnecessary > > > overhead so you should remove it like I already did in #v11. If it > > > wasn't the case, then mm_lock wouldn't be a definitive fix for the > > > race. > > > > There still could be junk in the cache of one cpu. If you just read the > > new pointer but use the earlier content pointed to then you have a > > problem. > > There can't be junk, spinlocks provides semantics of proper memory > barriers, just like rcu, so it's entirely superflous. > > There could be junk only if any of the mmu_notifier_* methods would be > invoked _outside_ the i_mmap_lock and _outside_ the anon_vma and > outside the mmap_sem, that is never the case of course.
So we use other locks to perform serialization on the list chains? Basically the list chains are protected by either mmap_sem or an rmap lock? We need to document that. In that case we could also add an unregister function. ------------------------------------------------------------------------- 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
