[PATCH v2] drm/amdkfd: don't use dqm lock during device reset/suspend/resume
Yang, Philip
Philip.Yang at amd.com
Tue Oct 22 19:19:08 UTC 2019
On 2019-10-22 2:40 p.m., Grodzovsky, Andrey wrote:
>
> On 10/22/19 2:38 PM, Grodzovsky, Andrey wrote:
>> On 10/22/19 2:28 PM, Yang, Philip wrote:
>>> If device reset/suspend/resume failed for some reason, dqm lock is
>>> hold forever and this causes deadlock. Below is a kernel backtrace when
>>> application open kfd after suspend/resume failed.
>>>
>>> Instead of holding dqm lock in pre_reset and releasing dqm lock in
>>> post_reset, add dqm->device_stopped flag which is modified in
>>> dqm->ops.start and dqm->ops.stop. The flag doesn't need lock protection
>>> because write/read are all inside dqm lock.
>>>
>>> For HWS case, map_queues_cpsch and unmap_queues_cpsch checks
>>> device_stopped flag before sending the updated runlist.
>>
>> Is there a chance of race condition here where dqm->device_stopped
>> returns true for some operation (e.g.map_queues_cpsch) but just as it
>> proceeds GPU reset starts ?
>>
>> Andrey
>
>
> Correction -
>
> dqm->device_stopped returns FALSE
>
No race condition here, dqm->device_stopped is set to FALSE in
kgd2kfd_post_reset -> dqm->ops.start(), which the last step of
amdgpu_device_gpu_recover, so it's safe to do map_queue_cpsch.
Regards,
Philip
> Andrey
>
>>
>>
>>> v2: For no-HWS case, when device is stopped, don't call
>>> load/destroy_mqd for eviction, restore and create queue, and avoid
>>> debugfs dump hdqs.
>>>
>>> Backtrace of dqm lock deadlock:
>>>
>>> [Thu Oct 17 16:43:37 2019] INFO: task rocminfo:3024 blocked for more
>>> than 120 seconds.
>>> [Thu Oct 17 16:43:37 2019] Not tainted
>>> 5.0.0-rc1-kfd-compute-rocm-dkms-no-npi-1131 #1
>>> [Thu Oct 17 16:43:37 2019] "echo 0 >
>>> /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>>> [Thu Oct 17 16:43:37 2019] rocminfo D 0 3024 2947
>>> 0x80000000
>>> [Thu Oct 17 16:43:37 2019] Call Trace:
>>> [Thu Oct 17 16:43:37 2019] ? __schedule+0x3d9/0x8a0
>>> [Thu Oct 17 16:43:37 2019] schedule+0x32/0x70
>>> [Thu Oct 17 16:43:37 2019] schedule_preempt_disabled+0xa/0x10
>>> [Thu Oct 17 16:43:37 2019] __mutex_lock.isra.9+0x1e3/0x4e0
>>> [Thu Oct 17 16:43:37 2019] ? __call_srcu+0x264/0x3b0
>>> [Thu Oct 17 16:43:37 2019] ? process_termination_cpsch+0x24/0x2f0
>>> [amdgpu]
>>> [Thu Oct 17 16:43:37 2019] process_termination_cpsch+0x24/0x2f0
>>> [amdgpu]
>>> [Thu Oct 17 16:43:37 2019]
>>> kfd_process_dequeue_from_all_devices+0x42/0x60 [amdgpu]
>>> [Thu Oct 17 16:43:37 2019] kfd_process_notifier_release+0x1be/0x220
>>> [amdgpu]
>>> [Thu Oct 17 16:43:37 2019] __mmu_notifier_release+0x3e/0xc0
>>> [Thu Oct 17 16:43:37 2019] exit_mmap+0x160/0x1a0
>>> [Thu Oct 17 16:43:37 2019] ? __handle_mm_fault+0xba3/0x1200
>>> [Thu Oct 17 16:43:37 2019] ? exit_robust_list+0x5a/0x110
>>> [Thu Oct 17 16:43:37 2019] mmput+0x4a/0x120
>>> [Thu Oct 17 16:43:37 2019] do_exit+0x284/0xb20
>>> [Thu Oct 17 16:43:37 2019] ? handle_mm_fault+0xfa/0x200
>>> [Thu Oct 17 16:43:37 2019] do_group_exit+0x3a/0xa0
>>> [Thu Oct 17 16:43:37 2019] __x64_sys_exit_group+0x14/0x20
>>> [Thu Oct 17 16:43:37 2019] do_syscall_64+0x4f/0x100
>>> [Thu Oct 17 16:43:37 2019] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>>
>>> Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
>>> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
>>> ---
>>> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 6 +--
>>> drivers/gpu/drm/amd/amdkfd/kfd_device.c | 5 --
>>> .../drm/amd/amdkfd/kfd_device_queue_manager.c | 47 +++++++++++++++++--
>>> .../drm/amd/amdkfd/kfd_device_queue_manager.h | 1 +
>>> 4 files changed, 46 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> index d9e36dbf13d5..40d75c39f08e 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
>>> @@ -120,13 +120,13 @@ static int kfd_open(struct inode *inode, struct file *filep)
>>> return -EPERM;
>>> }
>>>
>>> + if (kfd_is_locked())
>>> + return -EAGAIN;
>>> +
>>> process = kfd_create_process(filep);
>>> if (IS_ERR(process))
>>> return PTR_ERR(process);
>>>
>>> - if (kfd_is_locked())
>>> - return -EAGAIN;
>>> -
>>> dev_dbg(kfd_device, "process %d opened, compat mode (32 bit) - %d\n",
>>> process->pasid, process->is_32bit_user_mode);
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>> index 8f4b24e84964..4fa8834ce7cb 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
>>> @@ -730,9 +730,6 @@ int kgd2kfd_pre_reset(struct kfd_dev *kfd)
>>> return 0;
>>> kgd2kfd_suspend(kfd);
>>>
>>> - /* hold dqm->lock to prevent further execution*/
>>> - dqm_lock(kfd->dqm);
>>> -
>>> kfd_signal_reset_event(kfd);
>>> return 0;
>>> }
>>> @@ -750,8 +747,6 @@ int kgd2kfd_post_reset(struct kfd_dev *kfd)
>>> if (!kfd->init_complete)
>>> return 0;
>>>
>>> - dqm_unlock(kfd->dqm);
>>> -
>>> ret = kfd_resume(kfd);
>>> if (ret)
>>> return ret;
>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
>>> index 81fb545cf42c..82e1c6280d13 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
>>> @@ -340,6 +340,10 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
>>> mqd_mgr->init_mqd(mqd_mgr, &q->mqd, q->mqd_mem_obj,
>>> &q->gart_mqd_addr, &q->properties);
>>> if (q->properties.is_active) {
>>> + if (!dqm->sched_running) {
>>> + WARN_ONCE(1, "Load non-HWS mqd while stopped\n");
>>> + goto add_queue_to_list;
>>> + }
>>>
>>> if (WARN(q->process->mm != current->mm,
>>> "should only run in user thread"))
>>> @@ -351,6 +355,7 @@ static int create_queue_nocpsch(struct device_queue_manager *dqm,
>>> goto out_free_mqd;
>>> }
>>>
>>> +add_queue_to_list:
>>> list_add(&q->list, &qpd->queues_list);
>>> qpd->queue_count++;
>>> if (q->properties.is_active)
>>> @@ -458,6 +463,11 @@ static int destroy_queue_nocpsch_locked(struct device_queue_manager *dqm,
>>>
>>> deallocate_doorbell(qpd, q);
>>>
>>> + if (!dqm->sched_running) {
>>> + WARN_ONCE(1, "Destroy non-HWS queue while stopped\n");
>>> + return 0;
>>> + }
>>> +
>>> retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
>>> KFD_PREEMPT_TYPE_WAVEFRONT_RESET,
>>> KFD_UNMAP_LATENCY_MS,
>>> @@ -533,6 +543,12 @@ static int update_queue(struct device_queue_manager *dqm, struct queue *q)
>>> (q->properties.type == KFD_QUEUE_TYPE_COMPUTE ||
>>> q->properties.type == KFD_QUEUE_TYPE_SDMA ||
>>> q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)) {
>>> +
>>> + if (!dqm->sched_running) {
>>> + WARN_ONCE(1, "Update non-HWS queue while stopped\n");
>>> + goto out_unlock;
>>> + }
>>> +
>>> retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
>>> KFD_PREEMPT_TYPE_WAVEFRONT_DRAIN,
>>> KFD_UNMAP_LATENCY_MS, q->pipe, q->queue);
>>> @@ -602,6 +618,11 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
>>> mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
>>> q->properties.type)];
>>> q->properties.is_active = false;
>>> + dqm->queue_count--;
>>> +
>>> + if (!dqm->sched_running)
>>> + continue;
>>> +
>>> retval = mqd_mgr->destroy_mqd(mqd_mgr, q->mqd,
>>> KFD_PREEMPT_TYPE_WAVEFRONT_DRAIN,
>>> KFD_UNMAP_LATENCY_MS, q->pipe, q->queue);
>>> @@ -610,7 +631,6 @@ static int evict_process_queues_nocpsch(struct device_queue_manager *dqm,
>>> * maintain a consistent eviction state
>>> */
>>> ret = retval;
>>> - dqm->queue_count--;
>>> }
>>>
>>> out:
>>> @@ -711,6 +731,11 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
>>> mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
>>> q->properties.type)];
>>> q->properties.is_active = true;
>>> + dqm->queue_count++;
>>> +
>>> + if (!dqm->sched_running)
>>> + continue;
>>> +
>>> retval = mqd_mgr->load_mqd(mqd_mgr, q->mqd, q->pipe,
>>> q->queue, &q->properties, mm);
>>> if (retval && !ret)
>>> @@ -718,7 +743,6 @@ static int restore_process_queues_nocpsch(struct device_queue_manager *dqm,
>>> * maintain a consistent eviction state
>>> */
>>> ret = retval;
>>> - dqm->queue_count++;
>>> }
>>> qpd->evicted = 0;
>>> out:
>>> @@ -915,7 +939,8 @@ static int start_nocpsch(struct device_queue_manager *dqm)
>>>
>>> if (dqm->dev->device_info->asic_family == CHIP_HAWAII)
>>> return pm_init(&dqm->packets, dqm);
>>> -
>>> + dqm->sched_running = true;
>>> +
>>> return 0;
>>> }
>>>
>>> @@ -923,7 +948,8 @@ static int stop_nocpsch(struct device_queue_manager *dqm)
>>> {
>>> if (dqm->dev->device_info->asic_family == CHIP_HAWAII)
>>> pm_uninit(&dqm->packets);
>>> -
>>> + dqm->sched_running = false;
>>> +
>>> return 0;
>>> }
>>>
>>> @@ -1074,6 +1100,7 @@ static int start_cpsch(struct device_queue_manager *dqm)
>>> dqm_lock(dqm);
>>> /* clear hang status when driver try to start the hw scheduler */
>>> dqm->is_hws_hang = false;
>>> + dqm->sched_running = true;
>>> execute_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_DYNAMIC_QUEUES, 0);
>>> dqm_unlock(dqm);
>>>
>>> @@ -1089,6 +1116,7 @@ static int stop_cpsch(struct device_queue_manager *dqm)
>>> {
>>> dqm_lock(dqm);
>>> unmap_queues_cpsch(dqm, KFD_UNMAP_QUEUES_FILTER_ALL_QUEUES, 0);
>>> + dqm->sched_running = false;
>>> dqm_unlock(dqm);
>>>
>>> kfd_gtt_sa_free(dqm->dev, dqm->fence_mem);
>>> @@ -1275,9 +1303,10 @@ static int map_queues_cpsch(struct device_queue_manager *dqm)
>>> {
>>> int retval;
>>>
>>> + if (!dqm->sched_running)
>>> + return 0;
>>> if (dqm->queue_count <= 0 || dqm->processes_count <= 0)
>>> return 0;
>>> -
>>> if (dqm->active_runlist)
>>> return 0;
>>>
>>> @@ -1299,6 +1328,8 @@ static int unmap_queues_cpsch(struct device_queue_manager *dqm,
>>> {
>>> int retval = 0;
>>>
>>> + if (!dqm->sched_running)
>>> + return 0;
>>> if (dqm->is_hws_hang)
>>> return -EIO;
>>> if (!dqm->active_runlist)
>>> @@ -1903,6 +1934,12 @@ int dqm_debugfs_hqds(struct seq_file *m, void *data)
>>> int pipe, queue;
>>> int r = 0;
>>>
>>> + if (!dqm->sched_running) {
>>> + seq_printf(m, " Device is stopped\n");
>>> +
>>> + return 0;
>>> + }
>>> +
>>> r = dqm->dev->kfd2kgd->hqd_dump(dqm->dev->kgd,
>>> KFD_CIK_HIQ_PIPE, KFD_CIK_HIQ_QUEUE,
>>> &dump, &n_regs);
>>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
>>> index 2eaea6b04cbe..a8c37e6da027 100644
>>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
>>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
>>> @@ -201,6 +201,7 @@ struct device_queue_manager {
>>> bool is_hws_hang;
>>> struct work_struct hw_exception_work;
>>> struct kfd_mem_obj hiq_sdma_mqd;
>>> + bool sched_running;
>>> };
>>>
>>> void device_queue_manager_init_cik(
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