Re: [PATCH-tip v3 02/14] locking/rwsem: Make owner available even if !CONFIG_RWSEM_SPIN_ON_OWNER

From: Waiman Long
Date: Thu Apr 11 2019 - 12:03:19 EST


On 04/11/2019 04:12 AM, Peter Zijlstra wrote:
> On Wed, Apr 10, 2019 at 02:42:19PM -0400, Waiman Long wrote:
>> The owner field in the rw_semaphore structure is used primarily for
>> optimistic spinning. However, identifying the rwsem owner can also be
>> helpful in debugging as well as tracing locking related issues when
>> analyzing crash dump. The owner field may also store state information
>> that can be important to the operation of the rwsem.
>>
>> So the owner field is now made a permanent member of the rw_semaphore
>> structure irrespective of CONFIG_RWSEM_SPIN_ON_OWNER.
> sem->owner is still initialized under CONFIG_RWSEM_SPIN_ON_OWNER.

Oh, you are right. I missed that part. I will fix it in the next version.

Cheers,
Longman