Re: [PATCH v5 00/18] locking/rwsem: Rwsem rearchitecture part 2

Waiman Long
2019-04-19T18:35:45Z

On 04/19/2019 08:49 AM, Ingo Molnar wrote:
> * Ingo Molnar <mingo@kernel.org> wrote:
>
>> * Waiman Long <longman@redhat.com> wrote:
>>
>>> On 04/18/2019 07:46 PM, Waiman Long wrote:
>>>> v5:
>>>> - Drop v4 patch 1 as it is merged into tip's locking/core branch.
>>>> - Integrate the 2 followup patches into the series. The first
>>>> follow-up patch is broken into 2 pieces. The first piece comes in
>>>> before the "Enable readers spinning on writer" and the 2nd piece
>>>> is merged into the "Enable time-based spinning on reader-owned
>>>> rwsem" patch. The 2nd followup patch is added after that.
>>>> - Add a new patch to make all wake_up_q() calls after dropping
>>>> wait_lock as suggested by PeterZ.
>>>> - Incorporate numerouos suggestions by PeterZ and Davidlohr.
>>> This patchset is still being reviewed by Peter . The purpose of this
>>> series is mainly to sync up the version that Peter has and the ones that
>>> I am working on incorporating his feedback. Further changes may still be
>>> needed.
>>>
>>> I run an overall performance test on this new patchset and present the
>>> data in this cover letter. However, I haven't run performance tests for
>>> individual patches. So the performance data listed in some of the
>>> patches may be stale.
>> Just for those who'd like to follow the scope of changes, find below the
>> v4->v5 interdiff. v5 is now included in tip:WIP.locking/core, and also
>> merged into tip:master. (But not propagated towards linux-next yet.)
> Hm, I'm experiencing early boot hangs with v5, on defconfig-ish x86-64
> kernels:
>
> [ 0.153940] rcu: Hierarchical RCU implementation.
> [ 0.154289] rcu: RCU restricting CPUs from NR_CPUS=128 to nr_cpu_ids=17.
> [ 0.154829] rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies.
> [ 0.155390] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=17
>
>
> I bisected it back to the v5 version of this patch:
>
> 2fd5f60fa4c3: locking/rwsem: Merge owner into count on x86-64
>
> I'm moving -tip back to -v4 meanwhile.
>
> Thanks,
>
> Ingo

Sorry about that. Will look into that problem.

-Longman