This will display the sizes of kenrel BO's bound to an open file, which are
otherwise not exposed to UM through a handle.

The sizes recorded are as follows:
 - Per group: suspend buffer, protm-suspend buffer, syncobjcs
 - Per queue: ringbuffer, profiling slots, firmware interface
 - For all heaps in all heap pools across all VM's bound to an open file,
 record size of all heap chuks, and for each pool the gpu_context BO too.

This does not record the size of FW regions, as these aren't bound to a
specific open file and remain active through the whole life of the driver.

Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_drv.c   | 14 +++++++
 drivers/gpu/drm/panthor/panthor_heap.c  | 26 +++++++++++++
 drivers/gpu/drm/panthor/panthor_heap.h  |  2 +
 drivers/gpu/drm/panthor/panthor_mmu.c   | 34 +++++++++++++++++
 drivers/gpu/drm/panthor/panthor_mmu.h   |  3 ++
 drivers/gpu/drm/panthor/panthor_sched.c | 51 ++++++++++++++++++++++++-
 drivers/gpu/drm/panthor/panthor_sched.h |  2 +
 7 files changed, 131 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index ac7e53f6e3f0..b75a9251f578 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1457,12 +1457,26 @@ static void panthor_gpu_show_fdinfo(struct panthor_device *ptdev,
 	drm_printf(p, "drm-curfreq-panthor:\t%lu Hz\n", ptdev->current_frequency);
 }
 
+static void panthor_show_internal_memory_stats(struct drm_printer *p, struct drm_file *file)
+{
+	char *drv_name = file->minor->dev->driver->name;
+	struct panthor_file *pfile = file->driver_priv;
+	struct drm_memory_stats stats = {0};
+
+	panthor_group_kbo_sizes(pfile, &stats);
+	panthor_vm_heaps_sizes(pfile, &stats);
+
+	drm_fdinfo_print_size(p, drv_name, "resident", "memory", stats.resident);
+	drm_fdinfo_print_size(p, drv_name, "active", "memory", stats.active);
+}
+
 static void panthor_show_fdinfo(struct drm_printer *p, struct drm_file *file)
 {
 	struct drm_device *dev = file->minor->dev;
 	struct panthor_device *ptdev = container_of(dev, struct panthor_device, base);
 
 	panthor_gpu_show_fdinfo(ptdev, file->driver_priv, p);
+	panthor_show_internal_memory_stats(p, file);
 
 	drm_show_memory_stats(p, file);
 }
diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c
index 3796a9eb22af..db0285ce5812 100644
--- a/drivers/gpu/drm/panthor/panthor_heap.c
+++ b/drivers/gpu/drm/panthor/panthor_heap.c
@@ -603,3 +603,29 @@ void panthor_heap_pool_destroy(struct panthor_heap_pool *pool)
 
 	panthor_heap_pool_put(pool);
 }
+
+/**
+ * panthor_heap_pool_size() - Calculate size of all chunks across all heaps in a pool
+ * @pool: Pool whose total chunk size to calculate.
+ *
+ * This function adds the size of all heap chunks across all heaps in the
+ * argument pool. It also adds the size of the gpu contexts kernel bo.
+ * It is meant to be used by fdinfo for displaying the size of internal
+ * driver BO's that aren't exposed to userspace through a GEM handle.
+ *
+ */
+size_t panthor_heap_pool_size(struct panthor_heap_pool *pool)
+{
+	struct panthor_heap *heap;
+	unsigned long i;
+	size_t size = 0;
+
+	down_read(&pool->lock);
+	xa_for_each(&pool->xa, i, heap)
+		size += heap->chunk_size * heap->chunk_count;
+	up_read(&pool->lock);
+
+	size += pool->gpu_contexts->obj->size;
+
+	return size;
+}
diff --git a/drivers/gpu/drm/panthor/panthor_heap.h b/drivers/gpu/drm/panthor/panthor_heap.h
index 25a5f2bba445..e3358d4e8edb 100644
--- a/drivers/gpu/drm/panthor/panthor_heap.h
+++ b/drivers/gpu/drm/panthor/panthor_heap.h
@@ -27,6 +27,8 @@ struct panthor_heap_pool *
 panthor_heap_pool_get(struct panthor_heap_pool *pool);
 void panthor_heap_pool_put(struct panthor_heap_pool *pool);
 
+size_t panthor_heap_pool_size(struct panthor_heap_pool *pool);
+
 int panthor_heap_grow(struct panthor_heap_pool *pool,
 		      u64 heap_gpu_va,
 		      u32 renderpasses_in_flight,
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index c3f0b0225cf9..b43073010b7f 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -1941,6 +1941,40 @@ struct panthor_heap_pool *panthor_vm_get_heap_pool(struct panthor_vm *vm, bool c
 	return pool;
 }
 
+/**
+ * panthor_vm_heaps_sizes() - Calculate size of all heap chunks across all
+ * heaps over all the heap pools in a VM
+ * @pfile: File.
+ * @stats: Memory stats to be updated.
+ *
+ * Calculate all heap chunk sizes in all heap pools bound to a VM. If the VM
+ * is active, record the size as active as well.
+ */
+void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats)
+{
+	struct panthor_vm *vm;
+	unsigned long i;
+
+	if (!pfile->vms)
+		return;
+
+	xa_for_each(&pfile->vms->xa, i, vm) {
+		size_t size;
+
+		mutex_lock(&vm->heaps.lock);
+		if (!vm->heaps.pool) {
+			mutex_unlock(&vm->heaps.lock);
+			continue;
+		}
+		size = panthor_heap_pool_size(vm->heaps.pool);
+		mutex_unlock(&vm->heaps.lock);
+
+		stats->resident += size;
+		if (vm->as.id >= 0)
+			stats->active += size;
+	}
+}
+
 static u64 mair_to_memattr(u64 mair, bool coherent)
 {
 	u64 memattr = 0;
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.h b/drivers/gpu/drm/panthor/panthor_mmu.h
index 8d21e83d8aba..fc274637114e 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.h
+++ b/drivers/gpu/drm/panthor/panthor_mmu.h
@@ -9,6 +9,7 @@
 
 struct drm_exec;
 struct drm_sched_job;
+struct drm_memory_stats;
 struct panthor_gem_object;
 struct panthor_heap_pool;
 struct panthor_vm;
@@ -37,6 +38,8 @@ int panthor_vm_flush_all(struct panthor_vm *vm);
 struct panthor_heap_pool *
 panthor_vm_get_heap_pool(struct panthor_vm *vm, bool create);
 
+void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats);
+
 struct panthor_vm *panthor_vm_get(struct panthor_vm *vm);
 void panthor_vm_put(struct panthor_vm *vm);
 struct panthor_vm *panthor_vm_create(struct panthor_device *ptdev, bool for_mcu,
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index ef4bec7ff9c7..75b788c580a7 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -618,7 +618,7 @@ struct panthor_group {
 	 */
 	struct panthor_kernel_bo *syncobjs;
 
-	/** @fdinfo: Per-file total cycle and timestamp values reference. */
+	/** @fdinfo: Per-group total cycle and timestamp values and kernel BO sizes. */
 	struct {
 		/** @data: Total sampled values for jobs in queues from this group. */
 		struct panthor_gpu_usage data;
@@ -628,6 +628,9 @@ struct panthor_group {
 		 * and job post-completion processing function
 		 */
 		struct mutex lock;
+
+		/** @kbo_sizes: Aggregate size of private kernel BO's held by the group. */
+		size_t kbo_sizes;
 	} fdinfo;
 
 	/** @state: Group state. */
@@ -3365,6 +3368,29 @@ group_create_queue(struct panthor_group *group,
 	return ERR_PTR(ret);
 }
 
+static void add_group_kbo_sizes(struct panthor_device *ptdev,
+				struct panthor_group *group)
+{
+	struct panthor_queue *queue;
+	int i;
+
+	if (drm_WARN_ON(&ptdev->base, IS_ERR_OR_NULL(group)))
+		return;
+	if (drm_WARN_ON(&ptdev->base, ptdev != group->ptdev))
+		return;
+
+	group->fdinfo.kbo_sizes += group->suspend_buf->obj->size;
+	group->fdinfo.kbo_sizes += group->protm_suspend_buf->obj->size;
+	group->fdinfo.kbo_sizes += group->syncobjs->obj->size;
+
+	for (i = 0; i < group->queue_count; i++) {
+		queue =	group->queues[i];
+		group->fdinfo.kbo_sizes += queue->ringbuf->obj->size;
+		group->fdinfo.kbo_sizes += queue->iface.mem->obj->size;
+		group->fdinfo.kbo_sizes += queue->profiling.slots->obj->size;
+	}
+}
+
 #define MAX_GROUPS_PER_POOL		128
 
 int panthor_group_create(struct panthor_file *pfile,
@@ -3489,6 +3515,7 @@ int panthor_group_create(struct panthor_file *pfile,
 	}
 	mutex_unlock(&sched->reset.lock);
 
+	add_group_kbo_sizes(group->ptdev, group);
 	mutex_init(&group->fdinfo.lock);
 
 	return gid;
@@ -3606,6 +3633,28 @@ void panthor_group_pool_destroy(struct panthor_file *pfile)
 	pfile->groups = NULL;
 }
 
+/**
+ * panthor_group_kbo_sizes() - Retrieve aggregate size of all private kernel BO's
+ * belonging to all the groups owned by an open Panthor file
+ * @pfile: File.
+ * @stats: Memory statistics to be updated.
+ *
+ */
+void panthor_group_kbo_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats)
+{
+	struct panthor_group_pool *gpool = pfile->groups;
+	struct panthor_group *group;
+	unsigned long i;
+
+	if (IS_ERR_OR_NULL(gpool))
+		return;
+	xa_for_each(&gpool->xa, i, group) {
+		stats->resident += group->fdinfo.kbo_sizes;
+		if (group->csg_id >= 0)
+			stats->active += group->fdinfo.kbo_sizes;
+	}
+}
+
 static void job_release(struct kref *ref)
 {
 	struct panthor_job *job = container_of(ref, struct panthor_job, refcount);
diff --git a/drivers/gpu/drm/panthor/panthor_sched.h b/drivers/gpu/drm/panthor/panthor_sched.h
index 5ae6b4bde7c5..bfe26b26a15b 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.h
+++ b/drivers/gpu/drm/panthor/panthor_sched.h
@@ -9,6 +9,7 @@ struct dma_fence;
 struct drm_file;
 struct drm_gem_object;
 struct drm_sched_job;
+struct drm_memory_stats;
 struct drm_panthor_group_create;
 struct drm_panthor_queue_create;
 struct drm_panthor_group_get_state;
@@ -36,6 +37,7 @@ void panthor_job_update_resvs(struct drm_exec *exec, struct drm_sched_job *job);
 
 int panthor_group_pool_create(struct panthor_file *pfile);
 void panthor_group_pool_destroy(struct panthor_file *pfile);
+void panthor_group_kbo_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats);
 
 int panthor_sched_init(struct panthor_device *ptdev);
 void panthor_sched_unplug(struct panthor_device *ptdev);
-- 
2.47.1

On Tue, 14 Jan 2025 17:34:02 +0000
Adrián Larumbe <adrian.larumbe@collabora.com> wrote:

> This will display the sizes of kenrel BO's bound to an open file, which are
> otherwise not exposed to UM through a handle.
> 
> The sizes recorded are as follows:
>  - Per group: suspend buffer, protm-suspend buffer, syncobjcs
>  - Per queue: ringbuffer, profiling slots, firmware interface
>  - For all heaps in all heap pools across all VM's bound to an open file,
>  record size of all heap chuks, and for each pool the gpu_context BO too.
> 
> This does not record the size of FW regions, as these aren't bound to a
> specific open file and remain active through the whole life of the driver.
> 
> Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
> Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
> Reviewed-by: Steven Price <steven.price@arm.com>
> Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> ---
>  drivers/gpu/drm/panthor/panthor_drv.c   | 14 +++++++
>  drivers/gpu/drm/panthor/panthor_heap.c  | 26 +++++++++++++
>  drivers/gpu/drm/panthor/panthor_heap.h  |  2 +
>  drivers/gpu/drm/panthor/panthor_mmu.c   | 34 +++++++++++++++++
>  drivers/gpu/drm/panthor/panthor_mmu.h   |  3 ++
>  drivers/gpu/drm/panthor/panthor_sched.c | 51 ++++++++++++++++++++++++-
>  drivers/gpu/drm/panthor/panthor_sched.h |  2 +
>  7 files changed, 131 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index ac7e53f6e3f0..b75a9251f578 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1457,12 +1457,26 @@ static void panthor_gpu_show_fdinfo(struct panthor_device *ptdev,
>  	drm_printf(p, "drm-curfreq-panthor:\t%lu Hz\n", ptdev->current_frequency);
>  }
>  
> +static void panthor_show_internal_memory_stats(struct drm_printer *p, struct drm_file *file)
> +{
> +	char *drv_name = file->minor->dev->driver->name;
> +	struct panthor_file *pfile = file->driver_priv;
> +	struct drm_memory_stats stats = {0};
> +
> +	panthor_group_kbo_sizes(pfile, &stats);
> +	panthor_vm_heaps_sizes(pfile, &stats);
> +
> +	drm_fdinfo_print_size(p, drv_name, "resident", "memory", stats.resident);
> +	drm_fdinfo_print_size(p, drv_name, "active", "memory", stats.active);
> +}
> +
>  static void panthor_show_fdinfo(struct drm_printer *p, struct drm_file *file)
>  {
>  	struct drm_device *dev = file->minor->dev;
>  	struct panthor_device *ptdev = container_of(dev, struct panthor_device, base);
>  
>  	panthor_gpu_show_fdinfo(ptdev, file->driver_priv, p);
> +	panthor_show_internal_memory_stats(p, file);
>  
>  	drm_show_memory_stats(p, file);
>  }
> diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c
> index 3796a9eb22af..db0285ce5812 100644
> --- a/drivers/gpu/drm/panthor/panthor_heap.c
> +++ b/drivers/gpu/drm/panthor/panthor_heap.c
> @@ -603,3 +603,29 @@ void panthor_heap_pool_destroy(struct panthor_heap_pool *pool)
>  
>  	panthor_heap_pool_put(pool);
>  }
> +
> +/**
> + * panthor_heap_pool_size() - Calculate size of all chunks across all heaps in a pool
> + * @pool: Pool whose total chunk size to calculate.
> + *
> + * This function adds the size of all heap chunks across all heaps in the
> + * argument pool. It also adds the size of the gpu contexts kernel bo.
> + * It is meant to be used by fdinfo for displaying the size of internal
> + * driver BO's that aren't exposed to userspace through a GEM handle.
> + *
> + */
> +size_t panthor_heap_pool_size(struct panthor_heap_pool *pool)
> +{
> +	struct panthor_heap *heap;
> +	unsigned long i;
> +	size_t size = 0;
> +
> +	down_read(&pool->lock);
> +	xa_for_each(&pool->xa, i, heap)
> +		size += heap->chunk_size * heap->chunk_count;
> +	up_read(&pool->lock);
> +
> +	size += pool->gpu_contexts->obj->size;
> +
> +	return size;
> +}
> diff --git a/drivers/gpu/drm/panthor/panthor_heap.h b/drivers/gpu/drm/panthor/panthor_heap.h
> index 25a5f2bba445..e3358d4e8edb 100644
> --- a/drivers/gpu/drm/panthor/panthor_heap.h
> +++ b/drivers/gpu/drm/panthor/panthor_heap.h
> @@ -27,6 +27,8 @@ struct panthor_heap_pool *
>  panthor_heap_pool_get(struct panthor_heap_pool *pool);
>  void panthor_heap_pool_put(struct panthor_heap_pool *pool);
>  
> +size_t panthor_heap_pool_size(struct panthor_heap_pool *pool);
> +
>  int panthor_heap_grow(struct panthor_heap_pool *pool,
>  		      u64 heap_gpu_va,
>  		      u32 renderpasses_in_flight,
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index c3f0b0225cf9..b43073010b7f 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1941,6 +1941,40 @@ struct panthor_heap_pool *panthor_vm_get_heap_pool(struct panthor_vm *vm, bool c
>  	return pool;
>  }
>  
> +/**
> + * panthor_vm_heaps_sizes() - Calculate size of all heap chunks across all
> + * heaps over all the heap pools in a VM
> + * @pfile: File.
> + * @stats: Memory stats to be updated.
> + *
> + * Calculate all heap chunk sizes in all heap pools bound to a VM. If the VM
> + * is active, record the size as active as well.
> + */
> +void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats)
> +{
> +	struct panthor_vm *vm;
> +	unsigned long i;
> +
> +	if (!pfile->vms)
> +		return;
> +
> +	xa_for_each(&pfile->vms->xa, i, vm) {
> +		size_t size;
> +
> +		mutex_lock(&vm->heaps.lock);
> +		if (!vm->heaps.pool) {
> +			mutex_unlock(&vm->heaps.lock);
> +			continue;
> +		}
> +		size = panthor_heap_pool_size(vm->heaps.pool);
> +		mutex_unlock(&vm->heaps.lock);
> +
> +		stats->resident += size;
> +		if (vm->as.id >= 0)
> +			stats->active += size;
> +	}
> +}
> +
>  static u64 mair_to_memattr(u64 mair, bool coherent)
>  {
>  	u64 memattr = 0;
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.h b/drivers/gpu/drm/panthor/panthor_mmu.h
> index 8d21e83d8aba..fc274637114e 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.h
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.h
> @@ -9,6 +9,7 @@
>  
>  struct drm_exec;
>  struct drm_sched_job;
> +struct drm_memory_stats;
>  struct panthor_gem_object;
>  struct panthor_heap_pool;
>  struct panthor_vm;
> @@ -37,6 +38,8 @@ int panthor_vm_flush_all(struct panthor_vm *vm);
>  struct panthor_heap_pool *
>  panthor_vm_get_heap_pool(struct panthor_vm *vm, bool create);
>  
> +void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats);
> +
>  struct panthor_vm *panthor_vm_get(struct panthor_vm *vm);
>  void panthor_vm_put(struct panthor_vm *vm);
>  struct panthor_vm *panthor_vm_create(struct panthor_device *ptdev, bool for_mcu,
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index ef4bec7ff9c7..75b788c580a7 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -618,7 +618,7 @@ struct panthor_group {
>  	 */
>  	struct panthor_kernel_bo *syncobjs;
>  
> -	/** @fdinfo: Per-file total cycle and timestamp values reference. */
> +	/** @fdinfo: Per-group total cycle and timestamp values and kernel BO sizes. */

Each subfield is documented, so let's just say "Per-file info exposed
through /proc/<process>/fdinfo".

>  	struct {
>  		/** @data: Total sampled values for jobs in queues from this group. */
>  		struct panthor_gpu_usage data;
> @@ -628,6 +628,9 @@ struct panthor_group {
>  		 * and job post-completion processing function
>  		 */
>  		struct mutex lock;
> +
> +		/** @kbo_sizes: Aggregate size of private kernel BO's held by the group. */

@fdinfo.kbo_sizes otherwise the doc builder complains.

> +		size_t kbo_sizes;
>  	} fdinfo;
>  
>  	/** @state: Group state. */
> @@ -3365,6 +3368,29 @@ group_create_queue(struct panthor_group *group,
>  	return ERR_PTR(ret);
>  }
>  
> +static void add_group_kbo_sizes(struct panthor_device *ptdev,
> +				struct panthor_group *group)
> +{
> +	struct panthor_queue *queue;
> +	int i;
> +
> +	if (drm_WARN_ON(&ptdev->base, IS_ERR_OR_NULL(group)))
> +		return;
> +	if (drm_WARN_ON(&ptdev->base, ptdev != group->ptdev))
> +		return;
> +
> +	group->fdinfo.kbo_sizes += group->suspend_buf->obj->size;
> +	group->fdinfo.kbo_sizes += group->protm_suspend_buf->obj->size;
> +	group->fdinfo.kbo_sizes += group->syncobjs->obj->size;
> +
> +	for (i = 0; i < group->queue_count; i++) {
> +		queue =	group->queues[i];
> +		group->fdinfo.kbo_sizes += queue->ringbuf->obj->size;
> +		group->fdinfo.kbo_sizes += queue->iface.mem->obj->size;
> +		group->fdinfo.kbo_sizes += queue->profiling.slots->obj->size;
> +	}
> +}
> +
>  #define MAX_GROUPS_PER_POOL		128
>  
>  int panthor_group_create(struct panthor_file *pfile,
> @@ -3489,6 +3515,7 @@ int panthor_group_create(struct panthor_file *pfile,
>  	}
>  	mutex_unlock(&sched->reset.lock);
>  
> +	add_group_kbo_sizes(group->ptdev, group);
>  	mutex_init(&group->fdinfo.lock);
>  
>  	return gid;
> @@ -3606,6 +3633,28 @@ void panthor_group_pool_destroy(struct panthor_file *pfile)
>  	pfile->groups = NULL;
>  }
>  
> +/**
> + * panthor_group_kbo_sizes() - Retrieve aggregate size of all private kernel BO's
> + * belonging to all the groups owned by an open Panthor file
> + * @pfile: File.
> + * @stats: Memory statistics to be updated.
> + *
> + */
> +void panthor_group_kbo_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats)

The panthor_group prefix is a bit confusing since it's not applying to
a group but to all groups attached to a pfile. How about
panthor_fdinfo_gather_group_mem_info() to follow the
panthor_fdinfo_gather_group_samples() naming?

> +{
> +	struct panthor_group_pool *gpool = pfile->groups;
> +	struct panthor_group *group;
> +	unsigned long i;
> +
> +	if (IS_ERR_OR_NULL(gpool))
> +		return;

I suspect we need to take a lock to protect against group removal,
otherwise you might end up with a UAF.

> +	xa_for_each(&gpool->xa, i, group) {
> +		stats->resident += group->fdinfo.kbo_sizes;
> +		if (group->csg_id >= 0)
> +			stats->active += group->fdinfo.kbo_sizes;
> +	}
> +}
> +
>  static void job_release(struct kref *ref)
>  {
>  	struct panthor_job *job = container_of(ref, struct panthor_job, refcount);
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.h b/drivers/gpu/drm/panthor/panthor_sched.h
> index 5ae6b4bde7c5..bfe26b26a15b 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.h
> +++ b/drivers/gpu/drm/panthor/panthor_sched.h
> @@ -9,6 +9,7 @@ struct dma_fence;
>  struct drm_file;
>  struct drm_gem_object;
>  struct drm_sched_job;
> +struct drm_memory_stats;
>  struct drm_panthor_group_create;
>  struct drm_panthor_queue_create;
>  struct drm_panthor_group_get_state;
> @@ -36,6 +37,7 @@ void panthor_job_update_resvs(struct drm_exec *exec, struct drm_sched_job *job);
>  
>  int panthor_group_pool_create(struct panthor_file *pfile);
>  void panthor_group_pool_destroy(struct panthor_file *pfile);
> +void panthor_group_kbo_sizes(struct panthor_file *pfile, struct drm_memory_stats *stats);
>  
>  int panthor_sched_init(struct panthor_device *ptdev);
>  void panthor_sched_unplug(struct panthor_device *ptdev);