On 01/11/2019 02:11 PM, Koenig, Christian wrote:
Am 11.01.19 um 16:37 schrieb Grodzovsky, Andrey:
On 01/11/2019 04:42 AM, Koenig, Christian wrote:
Am 10.01.19 um 16:56 schrieb Grodzovsky, Andrey:
[SNIP]
But we will not be adding the cb back in drm_sched_stop
anymore, now we
are only going to add back the cb in drm_sched_startr after
rerunning
those jobs in drm_sched_resubmit_jobs and assign them a new parent
there
anyway.
Yeah, but when we find that we don't need to reset anything anymore
then adding the callbacks again won't be possible any more.
Christian.
I am not sure I understand it, can u point me to example of how this
will happen ? I am attaching my latest patches with waiting only for
the last job's fence here just so we are on same page regarding
the code.
Well the whole idea is to prepare all schedulers, then check once more
if the offending job hasn't completed in the meantime.
If the job completed we need to be able to rollback everything and
continue as if nothing had happened.
Christian.
Oh, but this piece of functionality - skipping HW ASIC reset in case
the
guilty job done is totally missing form this patch series and so needs
to be added. So what you say actually is that for the case were we skip
HW asic reset because the guilty job did complete we also need to skip
resubmitting the jobs in drm_sched_resubmit_jobs and hence preserve the
old parent fence pointer for reuse ? If so I would like to add all this
functionality as a third patch since the first 2 patches are more about
resolving race condition with jobs in flight while doing reset -
what do
you think ?
Yeah, sounds perfectly fine to me.
Christian.
I realized there is another complication now for XGMI hive use case,
we currently skip gpu recover for adev in case another gpu recover for
different adev in same hive is running, under the assumption that we
are going to reset all devices in hive anyway because that should
cover our own dev too. But if we chose to skip now HW asic reset if
our guilty job did finish we will aslo not HW reset any other devices
in the hive even if one of them might actually had a bad job, wanted
to do gpu recover but skipped it because our recover was in progress
in that time.
My general idea on that is to keep a list of guilty jobs per hive,
when you start gpu recover you first add you guilty job to the hive
and trylock hive->reset_lock. Any owner of hive->reset_lock (gpu
recovery in progress) once he finished his recovery and released
hive->reset_lock should go over hive->bad_jobs_list and if at least
one of them is still not signaled (not done) trigger another gpu
recovery and so on. If you do manage to trylock you also go over the
list, clean it and perform recovery. This list probably needs to be
protected with per hive lock.
I also think we can for now at least finish reviewing the first 2
patches and submit them since as I said before they are not dealing
with this topic and fixing existing race conditions. If you are OK
with that I can send for review the last iteration of the first 2
patches where I wait for the last fence in ring mirror list.
Andrey