Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-08 Thread Paul E. McKenney
On Wed, Feb 08, 2017 at 10:27:26AM +0100, Peter Zijlstra wrote: > On Tue, Feb 07, 2017 at 11:53:08AM -0800, Paul E. McKenney wrote: > > My usual question is "how often does the spinlock_debug code find a > > problem that would be hard to find otherwise?" Probably unanswerable > > given the nature

Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-08 Thread Peter Zijlstra
On Tue, Feb 07, 2017 at 11:53:08AM -0800, Paul E. McKenney wrote: > My usual question is "how often does the spinlock_debug code find a > problem that would be hard to find otherwise?" Probably unanswerable > given the nature of Linux-kernel development, but I figured I would ask > anyway. ;-) S

Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-07 Thread Paul E. McKenney
On Tue, Feb 07, 2017 at 02:46:31PM -0500, Waiman Long wrote: > On 02/07/2017 04:48 AM, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > >> On Thu, Feb 02, 2017 at 09:15:26AM -0500, Waiman Long wrote: > >>> v2->v3: > >>> - Keep the original v1 patches but move patch 3 of v2 in front so > >>>

Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-07 Thread Waiman Long
On 02/07/2017 04:48 AM, Ingo Molnar wrote: > * Peter Zijlstra wrote: > >> On Thu, Feb 02, 2017 at 09:15:26AM -0500, Waiman Long wrote: >>> v2->v3: >>> - Keep the original v1 patches but move patch 3 of v2 in front so >>> as to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is on. >>> >>>

Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-07 Thread Ingo Molnar
* Peter Zijlstra wrote: > On Thu, Feb 02, 2017 at 09:15:26AM -0500, Waiman Long wrote: > > v2->v3: > > - Keep the original v1 patches but move patch 3 of v2 in front so > > as to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is on. > > > > v1->v2: > > - Pack lockup and break_lock in

Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-07 Thread Peter Zijlstra
On Thu, Feb 02, 2017 at 09:15:26AM -0500, Waiman Long wrote: > v2->v3: > - Keep the original v1 patches but move patch 3 of v2 in front so > as to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is on. > > v1->v2: > - Pack lockup and break_lock into a single 4-byte slot so as not > t

[PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock

2017-02-02 Thread Waiman Long
v2->v3: - Keep the original v1 patches but move patch 3 of v2 in front so as to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is on. v1->v2: - Pack lockup and break_lock into a single 4-byte slot so as not to in increase spinlock size when GENERIC_LOCKBREAK is on. Hopefully tha