Hi Tim, On Wed, Nov 20, 2013 at 01:37:26AM +0000, Tim Chen wrote: > In this patch series, we separated out the MCS lock code which was > previously embedded in the mutex.c. This allows for easier reuse of > MCS lock in other places like rwsem and qrwlock. We also did some micro > optimizations and barrier cleanup. > > The original code has potential leaks between critical sections, which > was not a problem when MCS was embedded within the mutex but needs > to be corrected when allowing the MCS lock to be used by itself for > other locking purposes. > > Proper barriers are now embedded with the usage of smp_load_acquire() in > mcs_spin_lock() and smp_store_release() in mcs_spin_unlock. See > http://marc.info/?l=linux-arch&m=138386254111507 for info on the > new smp_load_acquire() and smp_store_release() functions. > > This patches were previously part of the rwsem optimization patch series > but now we spearate them out. > > We have also added hooks to allow for architecture specific > implementation of the mcs_spin_lock and mcs_spin_unlock functions. > > Will, do you want to take a crack at adding implementation for ARM > with wfe instruction? Sure, I'll have a go this week. Thanks for keeping that as a consideration! As an aside: what are you using to test this code, so that I can make sure I don't break it? Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>