linux-kernel - Re: [PATCH 2/3] drm/scheduler: Don't call wait_event

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Date:   Tue, 24 Apr 2018 11:51:46 -0400
From:   Andrey Grodzovsky <Andrey.Grodzovsky@....com>
To:     Michel Dänzer <michel@...nzer.net>,
        linux-kernel@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org
Cc:     David.Panariti@....com, oleg@...hat.com, ebiederm@...ssion.com,
        Alexander.Deucher@....com, akpm@...ux-foundation.org,
        Christian.Koenig@....com
Subject: Re: [PATCH 2/3] drm/scheduler: Don't call wait_event_killable for
 signaled process.



On 04/24/2018 11:46 AM, Michel Dänzer wrote:
> Adding the dri-devel list, since this is driver independent code.

Thanks, so many addresses that this one slipped out...
>
>
> On 2018-04-24 05:30 PM, Andrey Grodzovsky wrote:
>> Avoid calling wait_event_killable when you are possibly being called
>> from get_signal routine since in that case you end up in a deadlock
>> where you are alreay blocked in singla processing any trying to wait
> Multiple typos here, "[...] already blocked in signal processing and [...]"?

I don't understand where are the typos.

Andrey

>
>
>> on a new signal.
>>
>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@....com>
>> ---
>>   drivers/gpu/drm/scheduler/gpu_scheduler.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> index 088ff2b..09fd258 100644
>> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>> @@ -227,9 +227,10 @@ void drm_sched_entity_do_release(struct drm_gpu_scheduler *sched,
>>   		return;
>>   	/**
>>   	 * The client will not queue more IBs during this fini, consume existing
>> -	 * queued IBs or discard them on SIGKILL
>> +	 * queued IBs or discard them when in death signal state since
>> +	 * wait_event_killable can't receive signals in that state.
>>   	*/
>> -	if ((current->flags & PF_SIGNALED) && current->exit_code == SIGKILL)
>> +	if (current->flags & PF_SIGNALED)
>>   		entity->fini_status = -ERESTARTSYS;
>>   	else
>>   		entity->fini_status = wait_event_killable(sched->job_scheduled,
>>
>