[PATCH v7 2/4] drm: make drm-active- stats optional

Tvrtko Ursulin tvrtko.ursulin at igalia.com
Mon Nov 18 15:42:57 UTC 2024


On 18/11/2024 15:17, Li, Yunxiang (Teddy) wrote:
> [Public]
> 
>> From: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
>> Sent: Monday, November 11, 2024 5:30
>> On 10/11/2024 15:41, Yunxiang Li wrote:
>>> Make drm-active- optional just like drm-resident- and drm-purgeable-.
>>
>> As Jani has already commented the commit message needs some work.
>>
>>> Signed-off-by: Yunxiang Li <Yunxiang.Li at amd.com>
>>> CC: dri-devel at lists.freedesktop.org
>>> CC: intel-gfx at lists.freedesktop.org
>>> CC: amd-gfx at lists.freedesktop.org
>>> ---
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c |  1 +
>>>    drivers/gpu/drm/drm_file.c                 | 13 +++++++------
>>>    drivers/gpu/drm/i915/i915_drm_client.c     |  1 +
>>>    drivers/gpu/drm/xe/xe_drm_client.c         |  1 +
>>>    include/drm/drm_gem.h                      | 14 ++++++++------
>>>    5 files changed, 18 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
>>> index df2cf5c339255..7717e3e4f05b5 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
>>> @@ -97,6 +97,7 @@ void amdgpu_show_fdinfo(struct drm_printer *p,
>>> struct drm_file *file)
>>>
>>>              drm_print_memory_stats(p,
>>>                                     &stats[i].drm,
>>> +                                  DRM_GEM_OBJECT_ACTIVE |
>>>                                     DRM_GEM_OBJECT_RESIDENT |
>>>                                     DRM_GEM_OBJECT_PURGEABLE,
>>>                                     pl_name[i]);
>>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>>> index e285fcc28c59c..fd06671054723 100644
>>> --- a/drivers/gpu/drm/drm_file.c
>>> +++ b/drivers/gpu/drm/drm_file.c
>>> @@ -884,7 +884,9 @@ void drm_print_memory_stats(struct drm_printer *p,
>>>    {
>>>      print_size(p, "total", region, stats->private + stats->shared);
>>>      print_size(p, "shared", region, stats->shared);
>>> -   print_size(p, "active", region, stats->active);
>>> +
>>> +   if (supported_status & DRM_GEM_OBJECT_ACTIVE)
>>> +           print_size(p, "active", region, stats->active);
>>>
>>>      if (supported_status & DRM_GEM_OBJECT_RESIDENT)
>>>              print_size(p, "resident", region, stats->resident); @@ -917,15
>>> +919,13 @@ void drm_show_memory_stats(struct drm_printer *p, struct
>>> drm_file *file)
>>>
>>>              if (obj->funcs && obj->funcs->status) {
>>>                      s = obj->funcs->status(obj);
>>> -                   supported_status = DRM_GEM_OBJECT_RESIDENT |
>>> -                                   DRM_GEM_OBJECT_PURGEABLE;
>>> +                   supported_status |= s;
>>
>> I think this is correct and I think I've raised that it should be like this when the code
>> was originally added. I only don't remember what was the argument to keep it
>> hardcoded, if there was any. Adding Rob in case he can remember.
>>
>>>              }
>>>
>>> -           if (drm_gem_object_is_shared_for_memory_stats(obj)) {
>>> +           if (drm_gem_object_is_shared_for_memory_stats(obj))
>>>                      status.shared += obj->size;
>>> -           } else {
>>> +           else
>>>                      status.private += obj->size;
>>> -           }
>>
>> Drive by cleanup, okay.
>>
>>>
>>>              if (s & DRM_GEM_OBJECT_RESIDENT) {
>>>                      status.resident += add_size;
>>> @@ -938,6 +938,7 @@ void drm_show_memory_stats(struct drm_printer *p,
>>> struct drm_file *file)
>>>
>>>              if (!dma_resv_test_signaled(obj->resv, dma_resv_usage_rw(true))) {
>>>                      status.active += add_size;
>>> +                   supported_status |= DRM_GEM_OBJECT_ACTIVE;
>>
>> I wonder what behaviour we should have here if the driver has reported
>> DRM_GEM_OBJECT_ACTIVE via its status vfunc. Like should it be like this:
>>
>>      if ((s & DRM_GEM_OBJECT_ACTIVE) ||
>>          !dma_resv_test_signaled(obj->resv, dma_resv_usage_rw(true))) {
>>          ...
>>
>> ?
>>
>> So if some driver starts reporting this flag _and_ is still calling
>> drm_show_memory_stats(), it's version of activity tracking is used instead of the
>> the dma_resv based test.
> 
> I don't think that is feasible with the current API, because there's no way to differentiate "driver thinks a BO is not active" and "driver does not implement activity tracking". I think it's probably okay to keep it like this until someone wants to do it differently and refactor then.

Ah yes, good point. I actually initially thought the same (that we would 
need additional "supports active reporting" flag) but then for some 
reason convinced myself it is possible without it. I agree it works as is.

Regards,

Tvrtko

> 
> Teddy
> 
>>>
>>>                      /* If still active, don't count as purgeable: */
>>>                      s &= ~DRM_GEM_OBJECT_PURGEABLE;
>>> diff --git a/drivers/gpu/drm/i915/i915_drm_client.c
>>> b/drivers/gpu/drm/i915/i915_drm_client.c
>>> index f586825054918..168d7375304bc 100644
>>> --- a/drivers/gpu/drm/i915/i915_drm_client.c
>>> +++ b/drivers/gpu/drm/i915/i915_drm_client.c
>>> @@ -102,6 +102,7 @@ static void show_meminfo(struct drm_printer *p, struct
>> drm_file *file)
>>>      for_each_memory_region(mr, i915, id)
>>>              drm_print_memory_stats(p,
>>>                                     &stats[id],
>>> +                                  DRM_GEM_OBJECT_ACTIVE |
>>>                                     DRM_GEM_OBJECT_RESIDENT |
>>>                                     DRM_GEM_OBJECT_PURGEABLE,
>>>                                     mr->uabi_name);
>>> diff --git a/drivers/gpu/drm/xe/xe_drm_client.c
>>> b/drivers/gpu/drm/xe/xe_drm_client.c
>>> index 6a26923fa10e0..54941b4e850c4 100644
>>> --- a/drivers/gpu/drm/xe/xe_drm_client.c
>>> +++ b/drivers/gpu/drm/xe/xe_drm_client.c
>>> @@ -229,6 +229,7 @@ static void show_meminfo(struct drm_printer *p, struct
>> drm_file *file)
>>>              if (man) {
>>>                      drm_print_memory_stats(p,
>>>                                             &stats[mem_type],
>>> +                                          DRM_GEM_OBJECT_ACTIVE |
>>>                                             DRM_GEM_OBJECT_RESIDENT |
>>>                                             (mem_type != XE_PL_SYSTEM ? 0 :
>>>                                             DRM_GEM_OBJECT_PURGEABLE),
>> diff --git
>>> a/include/drm/drm_gem.h b/include/drm/drm_gem.h index
>>> bae4865b2101a..584ffdf5c2542 100644
>>> --- a/include/drm/drm_gem.h
>>> +++ b/include/drm/drm_gem.h
>>> @@ -48,19 +48,21 @@ struct drm_gem_object;
>>>     * enum drm_gem_object_status - bitmask of object state for fdinfo reporting
>>>     * @DRM_GEM_OBJECT_RESIDENT: object is resident in memory (ie. not
>> unpinned)
>>>     * @DRM_GEM_OBJECT_PURGEABLE: object marked as purgeable by
>>> userspace
>>> + * @DRM_GEM_OBJECT_ACTIVE: object is currently used by an active
>>> + submission
>>>     *
>>>     * Bitmask of status used for fdinfo memory stats, see
>>> &drm_gem_object_funcs.status
>>> - * and drm_show_fdinfo().  Note that an object can
>>> DRM_GEM_OBJECT_PURGEABLE if
>>> - * it still active or not resident, in which case drm_show_fdinfo()
>>> will not
>>> + * and drm_show_fdinfo().  Note that an object can report
>>> + DRM_GEM_OBJECT_PURGEABLE
>>> + * and be active or not resident, in which case drm_show_fdinfo()
>>> + will not
>>>     * account for it as purgeable.  So drivers do not need to check if
>>> the buffer
>>> - * is idle and resident to return this bit.  (Ie. userspace can mark
>>> a buffer
>>> - * as purgeable even while it is still busy on the GPU.. it does not
>>> _actually_
>>> - * become puregeable until it becomes idle.  The status gem object
>>> func does
>>> - * not need to consider this.)
>>> + * is idle and resident to return this bit, i.e. userspace can mark a
>>> + buffer as
>>> + * purgeable even while it is still busy on the GPU. It whill not get
>>> + reported
>>
>> Good cleanup.
>>
>> s/whill/will/
>>
>>> + * in the puregeable stats until it becomes idle.  The status gem
>>> + object func
>>> + * does not need to consider this.
>>>     */
>>>    enum drm_gem_object_status {
>>>      DRM_GEM_OBJECT_RESIDENT  = BIT(0),
>>>      DRM_GEM_OBJECT_PURGEABLE = BIT(1),
>>> +   DRM_GEM_OBJECT_ACTIVE = BIT(2),
>>>    };
>>>
>>>    /**
>>
>> Regards,
>>
>> Tvrtko


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