From: Luben Tuikov <luben.tuikov@amd.com>
To: christian.koenig@amd.com, Daniel Vetter <daniel@ffwll.ch>,
Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Cc: "Michel Dänzer" <michel@daenzer.net>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH v2 8/8] drm/amdgpu: Prevent any job recoveries after device is unplugged.
Date: Wed, 18 Nov 2020 10:43:13 -0500 [thread overview]
Message-ID: <5d40ed7d-10f4-a7ab-94a1-8749cd30b3be@amd.com> (raw)
In-Reply-To: <d0a3ee49-64f3-a223-7e84-0c8eb3481f61@gmail.com>
On 2020-11-18 07:01, Christian König wrote:
> Am 18.11.20 um 08:39 schrieb Daniel Vetter:
>> On Tue, Nov 17, 2020 at 9:07 PM Andrey Grodzovsky
>> <Andrey.Grodzovsky@amd.com> wrote:
>>>
>>> On 11/17/20 2:49 PM, Daniel Vetter wrote:
>>>> On Tue, Nov 17, 2020 at 02:18:49PM -0500, Andrey Grodzovsky wrote:
>>>>> On 11/17/20 1:52 PM, Daniel Vetter wrote:
>>>>>> On Tue, Nov 17, 2020 at 01:38:14PM -0500, Andrey Grodzovsky wrote:
>>>>>>> On 6/22/20 5:53 AM, Daniel Vetter wrote:
>>>>>>>> On Sun, Jun 21, 2020 at 02:03:08AM -0400, Andrey Grodzovsky wrote:
>>>>>>>>> No point to try recovery if device is gone, just messes up things.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
>>>>>>>>> ---
>>>>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 16 ++++++++++++++++
>>>>>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 8 ++++++++
>>>>>>>>> 2 files changed, 24 insertions(+)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>>>>> index 6932d75..5d6d3d9 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>>>>>>>>> @@ -1129,12 +1129,28 @@ static int amdgpu_pci_probe(struct pci_dev *pdev,
>>>>>>>>> return ret;
>>>>>>>>> }
>>>>>>>>> +static void amdgpu_cancel_all_tdr(struct amdgpu_device *adev)
>>>>>>>>> +{
>>>>>>>>> + int i;
>>>>>>>>> +
>>>>>>>>> + for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
>>>>>>>>> + struct amdgpu_ring *ring = adev->rings[i];
>>>>>>>>> +
>>>>>>>>> + if (!ring || !ring->sched.thread)
>>>>>>>>> + continue;
>>>>>>>>> +
>>>>>>>>> + cancel_delayed_work_sync(&ring->sched.work_tdr);
>>>>>>>>> + }
>>>>>>>>> +}
>>>>>>>> I think this is a function that's supposed to be in drm/scheduler, not
>>>>>>>> here. Might also just be your cleanup code being ordered wrongly, or your
>>>>>>>> split in one of the earlier patches not done quite right.
>>>>>>>> -Daniel
>>>>>>> This function iterates across all the schedulers per amdgpu device and accesses
>>>>>>> amdgpu specific structures , drm/scheduler deals with single scheduler at most
>>>>>>> so looks to me like this is the right place for this function
>>>>>> I guess we could keep track of all schedulers somewhere in a list in
>>>>>> struct drm_device and wrap this up. That was kinda the idea.
>>>>>>
>>>>>> Minimally I think a tiny wrapper with docs for the
>>>>>> cancel_delayed_work_sync(&sched->work_tdr); which explains what you must
>>>>>> observe to make sure there's no race.
>>>>> Will do
>>>>>
>>>>>
>>>>>> I'm not exactly sure there's no
>>>>>> guarantee here we won't get a new tdr work launched right afterwards at
>>>>>> least, so this looks a bit like a hack.
>>>>> Note that for any TDR work happening post amdgpu_cancel_all_tdr
>>>>> amdgpu_job_timedout->drm_dev_is_unplugged
>>>>> will return true and so it will return early. To make it water proof tight
>>>>> against race
>>>>> i can switch from drm_dev_is_unplugged to drm_dev_enter/exit
>>>> Hm that's confusing. You do a work_cancel_sync, so that at least looks
>>>> like "tdr work must not run after this point"
>>>>
>>>> If you only rely on drm_dev_enter/exit check with the tdr work, then
>>>> there's no need to cancel anything.
>>>
>>> Agree, synchronize_srcu from drm_dev_unplug should play the role
>>> of 'flushing' any earlier (in progress) tdr work which is
>>> using drm_dev_enter/exit pair. Any later arising tdr will terminate early when
>>> drm_dev_enter
>>> returns false.
>> Nope, anything you put into the work itself cannot close this race.
>> It's the schedule_work that matters here. Or I'm missing something ...
>> I thought that the tdr work you're cancelling here is launched by
>> drm/scheduler code, not by the amd callback?
>
> Yes that is correct. Canceling the work item is not the right approach
> at all, nor is adding dev_enter/exit pair in the recovery handler.
>
> What we need to do here is to stop the scheduler thread and then wait
> for any timeout handling to have finished.
>
> Otherwise it can scheduler a new timeout just after we have canceled
> this one.
Yep, that's exactly what I said in my email above.
Regards,
Luben
>
> Regards,
> Christian.
>
>> -Daniel
>>
>>> Will update.
>>>
>>> Andrey
>>>
>>>
>>>> For race free cancel_work_sync you need:
>>>> 1. make sure whatever is calling schedule_work is guaranteed to no longer
>>>> call schedule_work.
>>>> 2. call cancel_work_sync
>>>>
>>>> Anything else is cargo-culted work cleanup:
>>>>
>>>> - 1. without 2. means if a work got scheduled right before it'll still be
>>>> a problem.
>>>> - 2. without 1. means a schedule_work right after makes you calling
>>>> cancel_work_sync pointless.
>>>>
>>>> So either both or nothing.
>>>> -Daniel
>>>>
>>>>> Andrey
>>>>>
>>>>>
>>>>>> -Daniel
>>>>>>
>>>>>>> Andrey
>>>>>>>
>>>>>>>
>>>>>>>>> +
>>>>>>>>> static void
>>>>>>>>> amdgpu_pci_remove(struct pci_dev *pdev)
>>>>>>>>> {
>>>>>>>>> struct drm_device *dev = pci_get_drvdata(pdev);
>>>>>>>>> + struct amdgpu_device *adev = dev->dev_private;
>>>>>>>>> drm_dev_unplug(dev);
>>>>>>>>> + amdgpu_cancel_all_tdr(adev);
>>>>>>>>> ttm_bo_unmap_virtual_address_space(&adev->mman.bdev);
>>>>>>>>> amdgpu_driver_unload_kms(dev);
>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>>>>>> index 4720718..87ff0c0 100644
>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
>>>>>>>>> @@ -28,6 +28,8 @@
>>>>>>>>> #include "amdgpu.h"
>>>>>>>>> #include "amdgpu_trace.h"
>>>>>>>>> +#include <drm/drm_drv.h>
>>>>>>>>> +
>>>>>>>>> static void amdgpu_job_timedout(struct drm_sched_job *s_job)
>>>>>>>>> {
>>>>>>>>> struct amdgpu_ring *ring = to_amdgpu_ring(s_job->sched);
>>>>>>>>> @@ -37,6 +39,12 @@ static void amdgpu_job_timedout(struct drm_sched_job *s_job)
>>>>>>>>> memset(&ti, 0, sizeof(struct amdgpu_task_info));
>>>>>>>>> + if (drm_dev_is_unplugged(adev->ddev)) {
>>>>>>>>> + DRM_INFO("ring %s timeout, but device unplugged, skipping.\n",
>>>>>>>>> + s_job->sched->name);
>>>>>>>>> + return;
>>>>>>>>> + }
>>>>>>>>> +
>>>>>>>>> if (amdgpu_ring_soft_recovery(ring, job->vmid, s_job->s_fence->parent)) {
>>>>>>>>> DRM_ERROR("ring %s timeout, but soft recovered\n",
>>>>>>>>> s_job->sched->name);
>>>>>>>>> --
>>>>>>>>> 2.7.4
>>>>>>>>>
>>
>>
>
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next prev parent reply other threads:[~2020-11-18 15:43 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-21 6:03 [PATCH v2 0/8] RFC Support hot device unplug in amdgpu Andrey Grodzovsky
2020-06-21 6:03 ` [PATCH v2 1/8] drm: Add dummy page per device or GEM object Andrey Grodzovsky
2020-06-22 9:35 ` Daniel Vetter
2020-06-22 14:21 ` Pekka Paalanen
2020-06-22 14:24 ` Daniel Vetter
2020-06-22 14:28 ` Pekka Paalanen
2020-11-09 20:34 ` Andrey Grodzovsky
2020-11-15 6:39 ` Andrey Grodzovsky
2020-06-22 13:18 ` Christian König
2020-06-22 14:23 ` Daniel Vetter
2020-06-22 14:32 ` Andrey Grodzovsky
2020-06-22 17:45 ` Christian König
2020-06-22 17:50 ` Daniel Vetter
2020-11-09 20:53 ` Andrey Grodzovsky
2020-11-13 20:52 ` Andrey Grodzovsky
2020-11-14 8:41 ` Christian König
2020-11-14 9:51 ` Daniel Vetter
2020-11-14 9:57 ` Daniel Vetter
2020-11-16 9:42 ` Michel Dänzer
2020-11-15 6:34 ` Andrey Grodzovsky
2020-11-16 9:48 ` Christian König
2020-11-16 19:00 ` Andrey Grodzovsky
2020-11-16 20:36 ` Christian König
2020-11-16 20:42 ` Andrey Grodzovsky
2020-11-19 10:01 ` Christian König
2020-06-21 6:03 ` [PATCH v2 2/8] drm/ttm: Remap all page faults to per process dummy page Andrey Grodzovsky
2020-06-22 9:41 ` Daniel Vetter
2020-06-24 3:31 ` Andrey Grodzovsky
2020-06-24 7:19 ` Daniel Vetter
2020-11-10 17:41 ` Andrey Grodzovsky
2020-06-22 19:30 ` Christian König
2020-06-21 6:03 ` [PATCH v2 3/8] drm/ttm: Add unampping of the entire device address space Andrey Grodzovsky
2020-06-22 9:45 ` Daniel Vetter
2020-06-23 5:00 ` Andrey Grodzovsky
2020-06-23 10:25 ` Daniel Vetter
2020-06-23 12:55 ` Christian König
2020-06-22 19:37 ` Christian König
2020-06-22 19:47 ` Alex Deucher
2020-06-21 6:03 ` [PATCH v2 4/8] drm/amdgpu: Split amdgpu_device_fini into early and late Andrey Grodzovsky
2020-06-22 9:48 ` Daniel Vetter
2020-11-12 4:19 ` Andrey Grodzovsky
2020-11-12 9:29 ` Daniel Vetter
2020-06-21 6:03 ` [PATCH v2 5/8] drm/amdgpu: Refactor sysfs removal Andrey Grodzovsky
2020-06-22 9:51 ` Daniel Vetter
2020-06-22 11:21 ` Greg KH
2020-06-22 16:07 ` Andrey Grodzovsky
2020-06-22 16:45 ` Greg KH
2020-06-23 4:51 ` Andrey Grodzovsky
2020-06-23 6:05 ` Greg KH
2020-06-24 3:04 ` Andrey Grodzovsky
2020-06-24 6:11 ` Greg KH
2020-06-25 1:52 ` Andrey Grodzovsky
2020-11-10 17:54 ` Andrey Grodzovsky
2020-11-10 17:59 ` Greg KH
2020-11-11 15:13 ` Andrey Grodzovsky
2020-11-11 15:34 ` Greg KH
2020-11-11 15:45 ` Andrey Grodzovsky
2020-11-11 16:06 ` Greg KH
2020-11-11 16:34 ` Andrey Grodzovsky
2020-12-02 15:48 ` Andrey Grodzovsky
2020-12-02 17:34 ` Greg KH
2020-12-02 18:02 ` Andrey Grodzovsky
2020-12-02 18:20 ` Greg KH
2020-12-02 18:40 ` Andrey Grodzovsky
2020-06-22 13:19 ` Christian König
2020-06-21 6:03 ` [PATCH v2 6/8] drm/amdgpu: Unmap entire device address space on device remove Andrey Grodzovsky
2020-06-22 9:56 ` Daniel Vetter
2020-06-22 19:38 ` Christian König
2020-06-22 19:48 ` Alex Deucher
2020-06-23 10:22 ` Daniel Vetter
2020-06-23 13:16 ` Christian König
2020-06-24 3:12 ` Andrey Grodzovsky
2020-06-21 6:03 ` [PATCH v2 7/8] drm/amdgpu: Fix sdma code crash post device unplug Andrey Grodzovsky
2020-06-22 9:55 ` Daniel Vetter
2020-06-22 19:40 ` Christian König
2020-06-23 5:11 ` Andrey Grodzovsky
2020-06-23 7:14 ` Christian König
2020-06-21 6:03 ` [PATCH v2 8/8] drm/amdgpu: Prevent any job recoveries after device is unplugged Andrey Grodzovsky
2020-06-22 9:53 ` Daniel Vetter
2020-11-17 18:38 ` Andrey Grodzovsky
2020-11-17 18:52 ` Daniel Vetter
2020-11-17 19:18 ` Andrey Grodzovsky
2020-11-17 19:49 ` Daniel Vetter
2020-11-17 20:07 ` Andrey Grodzovsky
2020-11-18 7:39 ` Daniel Vetter
2020-11-18 12:01 ` Christian König
2020-11-18 15:43 ` Luben Tuikov [this message]
2020-11-18 16:20 ` Andrey Grodzovsky
2020-11-19 7:55 ` Christian König
2020-11-19 15:02 ` Andrey Grodzovsky
2020-11-19 15:29 ` Daniel Vetter
2020-11-19 21:24 ` Andrey Grodzovsky
2020-11-18 0:46 ` Luben Tuikov
2020-06-22 9:46 ` [PATCH v2 0/8] RFC Support hot device unplug in amdgpu Daniel Vetter
2020-06-23 5:14 ` Andrey Grodzovsky
2020-06-23 9:04 ` Michel Dänzer
2020-06-24 3:21 ` Andrey Grodzovsky
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