On Sun, Jan 25, 2015 at 11:36:06PM -0800, Davidlohr Bueso wrote: > In order to optimize the spinning step, we need to set the lock > owner as soon as the lock is acquired; after a successful counter > cmpxchg operation, that is. This is particularly useful as rwsems > need to set the owner to nil for readers, so there is a greater > chance of falling out of the spinning. Currently we only set the > owner much later in the game, in the more generic level -- latency > can be specially bad when waiting for a node->next pointer when > releasing the osq in up_write calls. > > As such, update the owner inside rwsem_try_write_lock (when the > lock is obtained after blocking) and rwsem_try_write_lock_unqueued > (when the lock is obtained while spinning). This requires creating > a new internal rwsem.h header to share the owner related calls. > > Also cleanup some headers for mutex and rwsem.
This is the thing I suggested lkml.kernel.org/r/20150108103708.ge29...@twins.programming.kicks-ass.net there right? Do you have numbers for how much this gained? -- 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/
