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

From: Waiman Long
Date: Fri Apr 12 2019 - 10:04:16 EST

On 04/12/2019 03:09 AM, Ingo Molnar wrote:
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>> On Fri, Apr 12, 2019 at 09:02:09AM +0200, Ingo Molnar wrote:
>>> * Waiman Long <longman@xxxxxxxxxx> wrote:
>>>> 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.
>>> Could you please post the next series against tip:WIP.locking/core, which
>>> is already being dogfood-ed in -tip and which I'm running on my desktop?
>>> I'll backmerge any fixes as needed/requested.
>> Urgh, please no, that's going to be hell to review :/
> Ok - full patches then. I'll handle the fallout.
> Thanks,
> Ingo

I will post an updated patchset later today.

Sorry for the omission.