[PATCH v2 3/6] drm/panfrost: Add fdinfo support for memory stats

[Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>]

A new DRM GEM object function is added so that drm_show_memory_stats can
provider more accurate memory usage numbers.

Ideally, in panfrost_gem_status, the BO's purgeable flag would be checked
after locking the driver's shrinker mutex, but drm_show_memory_stats takes
over the drm file's object handle database spinlock, so there's potential
for a race condition here.

Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panfrost/panfrost_drv.c |  9 +++++++--
 drivers/gpu/drm/panfrost/panfrost_gem.c | 12 ++++++++++++
 drivers/gpu/drm/panfrost/panfrost_gem.h |  1 +
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 3fd372301019..93d5f5538c0b 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -440,11 +440,14 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
 	args->retained = drm_gem_shmem_madvise(&bo->base, args->madv);
 
 	if (args->retained) {
-		if (args->madv == PANFROST_MADV_DONTNEED)
+		if (args->madv == PANFROST_MADV_DONTNEED) {
 			list_move_tail(&bo->base.madv_list,
 				       &pfdev->shrinker_list);
-		else if (args->madv == PANFROST_MADV_WILLNEED)
+			bo->is_purgable = true;
+		} else if (args->madv == PANFROST_MADV_WILLNEED) {
 			list_del_init(&bo->base.madv_list);
+			bo->is_purgable = false;
+		}
 	}
 
 out_unlock_mappings:
@@ -559,6 +562,8 @@ static void panfrost_show_fdinfo(struct drm_printer *p, struct drm_file *file)
 	struct panfrost_device *pfdev = dev->dev_private;
 
 	panfrost_gpu_show_fdinfo(pfdev, file->driver_priv, p);
+
+	drm_show_memory_stats(p, file);
 }
 
 static const struct file_operations panfrost_drm_driver_fops = {
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 3c812fbd126f..aea16b0e4dda 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -195,6 +195,17 @@ static int panfrost_gem_pin(struct drm_gem_object *obj)
 	return drm_gem_shmem_pin(&bo->base);
 }
 
+static enum drm_gem_object_status panfrost_gem_status(struct drm_gem_object *obj)
+{
+	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
+	enum drm_gem_object_status res = 0;
+
+	res |= (bo->is_purgable) ? DRM_GEM_OBJECT_PURGEABLE : 0;
+
+	res |= (bo->base.pages) ? DRM_GEM_OBJECT_RESIDENT : 0;
+
+	return res;
+}
 static const struct drm_gem_object_funcs panfrost_gem_funcs = {
 	.free = panfrost_gem_free_object,
 	.open = panfrost_gem_open,
@@ -206,6 +217,7 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = {
 	.vmap = drm_gem_shmem_object_vmap,
 	.vunmap = drm_gem_shmem_object_vunmap,
 	.mmap = drm_gem_shmem_object_mmap,
+	.status = panfrost_gem_status,
 	.vm_ops = &drm_gem_shmem_vm_ops,
 };
 
diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
index ad2877eeeccd..e06f7ceb8f73 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
@@ -38,6 +38,7 @@ struct panfrost_gem_object {
 
 	bool noexec		:1;
 	bool is_heap		:1;
+	bool is_purgable	:1;
 };
 
 struct panfrost_gem_mapping {
-- 
2.42.0