Re: [PATCH v8 3/6] MCS Lock: optimizations and extra comments

2014-01-21 Thread Tim Chen
On Tue, 2014-01-21 at 11:26 +0100, Peter Zijlstra wrote: > On Mon, Jan 20, 2014 at 05:24:28PM -0800, Tim Chen wrote: > > From: Jason Low > > > > Remove unnecessary operation to assign locked status to 1 if lock is > > acquired without contention as this value will not be checked by lock > > holde

Re: [PATCH v8 3/6] MCS Lock: optimizations and extra comments

2014-01-21 Thread Peter Zijlstra
On Mon, Jan 20, 2014 at 05:24:28PM -0800, Tim Chen wrote: > From: Jason Low > > Remove unnecessary operation to assign locked status to 1 if lock is > acquired without contention as this value will not be checked by lock > holder again and other potential lock contenders will not be looking at >

Re: [PATCH v8 3/6] MCS Lock: optimizations and extra comments

2014-01-21 Thread Peter Zijlstra
On Mon, Jan 20, 2014 at 05:24:28PM -0800, Tim Chen wrote: > @@ -41,8 +47,11 @@ void mcs_spin_lock(struct mcs_spinlock **lock, struct > mcs_spinlock *node) > > prev = xchg(lock, node); > if (likely(prev == NULL)) { > - /* Lock acquired */ > - node->locked = 1;