On Tue, 2014-01-28 at 21:54 +0100, Peter Zijlstra wrote: > On Tue, Jan 28, 2014 at 11:13:15AM -0800, Jason Low wrote: > > This RFC patch disables preemption between modifying lock->owner and > > locking/unlocking the mutex lock. This prevents situations where the owner > > can preempt between those 2 operations, which causes optimistic spinners to > > be unable to check if lock->owner is not on CPU. As mentioned in the > > thread for this v1 patchset, disabling preemption is a cheap operation. > > In that same thread it was also said that this wasn't really an issue at > all. So what is the justification?
This patch is mainly just a complementary patch for patch 5 so that we can allow the spinner to wait slightly longer for lock->count to get set without worrying about need_resched()/owner getting preempted. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/