[PATCH 3/5] drm/amdkfd: add page fault SMI event

Felix Kuehling felix.kuehling at amd.com
Fri Jan 14 22:37:21 UTC 2022


Am 2022-01-14 um 3:38 p.m. schrieb Philip Yang:
> After GPU page fault is recovered, output timestamp when fault is
> received, duration to recover the fault, if migration or only
> GPU page table is updated, fault address, read or write fault.
>
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c | 41 +++++++++++++++++++++
>  drivers/gpu/drm/amd/amdkfd/kfd_smi_events.h |  3 ++
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c        | 12 ++++--
>  3 files changed, 53 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> index 5818ea8ad4ce..6ed3d85348d6 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.c
> @@ -265,6 +265,47 @@ void kfd_smi_event_update_vmfault(struct kfd_dev *dev, uint16_t pasid)
>  	add_event_to_kfifo(task_info.pid, dev, KFD_SMI_EVENT_VMFAULT, fifo_in, len);
>  }
>  
> +static bool kfd_smi_event_pid_duration(struct kfd_dev *dev, uint16_t pasid,
> +				       pid_t *pid, uint64_t ts,
> +				       uint64_t *duration)
> +{
> +	struct amdgpu_task_info task_info = {0};
> +
> +	if (list_empty(&dev->smi_clients))
> +		return false;
> +
> +	amdgpu_vm_get_task_info(dev->adev, pasid, &task_info);

The caller (svm_range_restore_pages) already knows the kfd_process. It
should be able to provide the pid directly from p->lead_thread.pid. No
need to look that up from the pasid and vm task info.


> +	if (!task_info.pid) {
> +		pr_debug("task is gone\n");
> +		return false;
> +	}
> +	if (pid)
> +		*pid = task_info.pid;
> +	if (duration)
> +		*duration = ktime_get_ns() - ts;
> +	return true;
> +}
> +
> +void kfd_smi_event_page_fault(struct kfd_dev *dev, uint16_t pasid,
> +			      unsigned long address, bool migration,
> +			      bool write_fault, uint64_t ts)
> +{
> +	char fifo_in[128];
> +	uint64_t duration;
> +	pid_t pid;
> +	int len;
> +
> +	if (!kfd_smi_event_pid_duration(dev, pasid, &pid, ts, &duration))
> +		return;
> +
> +	len = snprintf(fifo_in, sizeof(fifo_in), "%d ts=%lld duration=%lld"
> +		       " pid=%d pfn=0x%lx write=%d migration=%d\n",

Please don't break the string over several lines. I believe that would
also trigger a checkpatch warning.


> +		       KFD_SMI_EVENT_PAGE_FAULT, ts, duration, pid, address,
> +		       write_fault, migration);

The existing events use %x for all numbers, including event number and
pid. Maybe better to stick with that convention for consistency. At
least for the event number.

The existing events seems to favor a very compact layout. I could think
of ways to make this event more compact as well (still using decimal for
some things for readability):

"%x %d(%d)-%d @%x %c%c", KFD_SMI_EVENT_PAGE_FAULT, ts, duration, pid,
address, write ? 'W' : 'w', migration ? 'M' : 'm'


> +
> +	add_event_to_kfifo(pid, dev, KFD_SMI_EVENT_PAGE_FAULT, fifo_in, len);
> +}
> +
>  int kfd_smi_event_open(struct kfd_dev *dev, uint32_t *fd)
>  {
>  	struct kfd_smi_client *client;
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.h b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.h
> index bffd0c32b060..fa3a8fdad69f 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_smi_events.h
> @@ -28,5 +28,8 @@ void kfd_smi_event_update_vmfault(struct kfd_dev *dev, uint16_t pasid);
>  void kfd_smi_event_update_thermal_throttling(struct kfd_dev *dev,
>  					     uint64_t throttle_bitmask);
>  void kfd_smi_event_update_gpu_reset(struct kfd_dev *dev, bool post_reset);
> +void kfd_smi_event_page_fault(struct kfd_dev *dev, uint16_t pasid,
> +			      unsigned long address, bool migration,
> +			      bool write_fault, uint64_t ts);
>  
>  #endif
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 37b3191615b6..b81667162dc1 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -32,6 +32,7 @@
>  #include "kfd_priv.h"
>  #include "kfd_svm.h"
>  #include "kfd_migrate.h"
> +#include "kfd_smi_events.h"
>  
>  #ifdef dev_fmt
>  #undef dev_fmt
> @@ -2657,11 +2658,12 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
>  	struct svm_range_list *svms;
>  	struct svm_range *prange;
>  	struct kfd_process *p;
> -	uint64_t timestamp;
> +	uint64_t timestamp = ktime_get_ns();

kfd_ioctl_get_clock_counters uses ktime_get_boottime_ns for the
system_clock_counter. We should use the same here (and in the duration
calculation) to make it possible to correlate timestamps from different
KFD APIs.


>  	int32_t best_loc;
>  	int32_t gpuidx = MAX_GPU_INSTANCE;
>  	bool write_locked = false;
>  	struct vm_area_struct *vma;
> +	bool migration = false;
>  	int r = 0;
>  
>  	if (!KFD_IS_SVM_API_SUPPORTED(adev->kfd.dev)) {
> @@ -2737,9 +2739,9 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
>  		goto out_unlock_range;
>  	}
>  
> -	timestamp = ktime_to_us(ktime_get()) - prange->validate_timestamp;
>  	/* skip duplicate vm fault on different pages of same range */
> -	if (timestamp < AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING) {
> +	if ((ktime_to_us(timestamp) -  prange->validate_timestamp) <
> +	    AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING) {

ktime_to_us takes a ktime_t. But timestamp is just a time in
nanoseconds. I think the correct conversion is just div_u64(timestamp,
1000).

Regards,
  Felix


>  		pr_debug("svms 0x%p [0x%lx %lx] already restored\n",
>  			 svms, prange->start, prange->last);
>  		r = 0;
> @@ -2776,6 +2778,7 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
>  		 prange->actual_loc);
>  
>  	if (prange->actual_loc != best_loc) {
> +		migration = true;
>  		if (best_loc) {
>  			r = svm_migrate_to_vram(prange, best_loc, mm);
>  			if (r) {
> @@ -2804,6 +2807,9 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
>  		pr_debug("failed %d to map svms 0x%p [0x%lx 0x%lx] to gpus\n",
>  			 r, svms, prange->start, prange->last);
>  
> +	kfd_smi_event_page_fault(adev->kfd.dev, p->pasid, addr, migration,
> +				 write_fault, timestamp);
> +
>  out_unlock_range:
>  	mutex_unlock(&prange->migrate_mutex);
>  out_unlock_svms:


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