On Wed, May 07, 2008 at 06:12:32PM -0700, Christoph Lameter wrote: > Andrea's mm_lock could have wider impact. It is the first effective > way that I have seen of temporarily holding off reclaim from an address > space. It sure is a brute force approach.
The only improvement I can imagine on mm_lock, is after changing the name to global_mm_lock() to reestablish the signal_pending check in the loop that takes the spinlock and to backoff and put the cap to 512 vmas so the ram wasted on anon-vmas wouldn't save more than 10-100usec at most (plus the vfree that may be a bigger cost but we're ok to pay it and it surely isn't security related). Then on the long term we need to talk to Matt on returning a parameter to the sort function to break the loop. After that we remove the 512 vma cap and mm_lock is free to run as long as it wants like /dev/urandom, nobody can care less how long it will run before returning as long as it reacts to signals. This is the right way if we want to support XPMEM/GRU efficiently and without introducing unnecessary regressions in the VM fastpaths and VM footprint. ------------------------------------------------------------------------- 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. 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
