lkml.org 
[lkml]   [2018]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v1] kthread/smpboot: Serialize kthread parking against wakeup
From
Date
HI ,

In the latest patch mentioned, k should be their instead of p:

-WARN_ON_ONCE(!wait_task_inactive(p, TASK_PARKED))
+WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED))

Regards
Gaurav

On 6/7/2018 12:29 AM, Peter Zijlstra wrote:
> On Wed, Jun 06, 2018 at 03:51:16PM +0200, Oleg Nesterov wrote:
>> IIUC, this will only affect smpboot_update_cpumask_percpu_thread() which can hit
>> an already parked thread, but it doesn't need to wait.
>>
>> And it seems that smpboot_update_cpumask_percpu_thread() in turn needs some cleanups.
>> Hmm. and its single user: kernel/watchdog.c.
>>
>> And speaking of watchdog.c, can't we simply kill the "watchdog/%u" threads? This is
>> off-topic, but can't watchdog_timer_fn() use stop_one_cpu_nowait(watchdog) ?
>>
>> And I really think we should unexport kthread_park/unpark(), only smpboot_thread_fn()
>> should use them. kthread() should not play with __kthread_parkme(). And even
>> KTHREAD_SHOULD_PARK must die, I mean it should live in struct smp_hotplug_thread,
>> not in struct kthread.
>>
>> OK, this is off-topic too.
>
>> And, let me repeat, can't we avoid complete_all() ?
>
> Yes, or at least if that watchdog crap is the only user.
>
> I have most of the patch reworking watchdog.c to use stop_one_cpu*(),
> and that cleans up lots -- of course, I've not tested it yet, so it
> could also be breaking lots :-)
>

--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.

\
 
 \ /
  Last update: 2018-06-07 10:31    [W:0.104 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site