[Linaro-mm-sig] Re: [PATCH v3 4/5] drm/panfrost: show device-wide list of DRM GEM objects over DebugFS

On 20/05/2025 18:44, Adrián Larumbe wrote:

This change is essentially a Panfrost port of commit a3707f53eb3f ("drm/panthor: show device-wide list of DRM GEM objects over DebugFS").

The DebugFS file is almost the same as in Panthor, minus the GEM object usage flags, since Panfrost has no kernel-only BO's.

Two additional GEM state flags which are displayed but aren't relevant to Panthor are 'Purged' and 'Purgeable', since Panfrost implements an explicit shrinker and a madvise ioctl to flag objects as reclaimable.

Signed-off-by: Adrián Larumbe adrian.larumbe@collabora.com

Reviewed-by: Steven Price steven.price@arm.com

---

drivers/gpu/drm/panfrost/panfrost_device.c | 5 + drivers/gpu/drm/panfrost/panfrost_device.h | 15 +++ drivers/gpu/drm/panfrost/panfrost_drv.c | 35 ++++++ drivers/gpu/drm/panfrost/panfrost_gem.c | 134 +++++++++++++++++++++ drivers/gpu/drm/panfrost/panfrost_gem.h | 47 ++++++++ 5 files changed, 236 insertions(+)

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c index 5d35076b2e6d..04bec27449cb 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.c +++ b/drivers/gpu/drm/panfrost/panfrost_device.c @@ -209,6 +209,11 @@ int panfrost_device_init(struct panfrost_device *pfdev) spin_lock_init(&pfdev->cycle_counter.lock); +#ifdef CONFIG_DEBUG_FS

• mutex_init(&pfdev->debugfs.gems_lock);
• INIT_LIST_HEAD(&pfdev->debugfs.gems_list);

+#endif

• err = panfrost_pm_domain_init(pfdev); if (err) return err;

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h index dcff70f905cd..077525a3ad68 100644 --- a/drivers/gpu/drm/panfrost/panfrost_device.h +++ b/drivers/gpu/drm/panfrost/panfrost_device.h @@ -111,6 +111,17 @@ struct panfrost_compatible { u8 gpu_quirks; }; +/**

• • struct panfrost_device_debugfs - Device-wide DebugFS tracking structures
• */

+struct panfrost_device_debugfs {

• /** @gems_list: Device-wide list of GEM objects owned by at least one file. */
• struct list_head gems_list;
• /** @gems_lock: Serializes access to the device-wide list of GEM objects. */
• struct mutex gems_lock;

+};

struct panfrost_device { struct device *dev; struct drm_device *ddev; @@ -164,6 +175,10 @@ struct panfrost_device { atomic_t use_count; spinlock_t lock; } cycle_counter;

+#ifdef CONFIG_DEBUG_FS

• struct panfrost_device_debugfs debugfs;

+#endif }; struct panfrost_mmu { diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index 179fbaa1cd0c..f576cb215898 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -13,6 +13,7 @@ #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <drm/panfrost_drm.h> +#include <drm/drm_debugfs.h> #include <drm/drm_drv.h> #include <drm/drm_ioctl.h> #include <drm/drm_syncobj.h> @@ -659,6 +660,37 @@ static const struct file_operations panfrost_drm_driver_fops = { .show_fdinfo = drm_show_fdinfo, }; +#ifdef CONFIG_DEBUG_FS +static int panthor_gems_show(struct seq_file *m, void *data) +{

• struct drm_info_node *node = m->private;
• struct drm_device *dev = node->minor->dev;
• struct panfrost_device *pfdev = dev->dev_private;
• panfrost_gem_debugfs_print_bos(pfdev, m);
• return 0;

+}

+static struct drm_info_list panthor_debugfs_list[] = {

• {"gems", panthor_gems_show, 0, NULL},

+};

+static int panthor_gems_debugfs_init(struct drm_minor *minor) +{

• drm_debugfs_create_files(panthor_debugfs_list,

• 		 ARRAY_SIZE(panthor_debugfs_list),
  

• 		 minor->debugfs_root, minor);
  

• return 0;

+}

+static void panfrost_debugfs_init(struct drm_minor *minor) +{

• panthor_gems_debugfs_init(minor);

+} +#endif

/*

• Panfrost driver version:
• • 1.0 - initial interface

@@ -683,6 +715,9 @@ static const struct drm_driver panfrost_drm_driver = { .gem_create_object = panfrost_gem_create_object, .gem_prime_import_sg_table = panfrost_gem_prime_import_sg_table, +#ifdef CONFIG_DEBUG_FS

• .debugfs_init = panfrost_debugfs_init,

+#endif }; static int panfrost_probe(struct platform_device *pdev) diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index 04483d5fb45d..bb73f2a68a12 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -12,6 +12,36 @@ #include "panfrost_gem.h" #include "panfrost_mmu.h" +#ifdef CONFIG_DEBUG_FS +static void panfrost_gem_debugfs_bo_add(struct panfrost_device *pfdev,

• 			struct panfrost_gem_object *bo)
  

+{

• bo->debugfs.creator.tgid = current->group_leader->pid;
• get_task_comm(bo->debugfs.creator.process_name, current->group_leader);
• mutex_lock(&pfdev->debugfs.gems_lock);
• list_add_tail(&bo->debugfs.node, &pfdev->debugfs.gems_list);
• mutex_unlock(&pfdev->debugfs.gems_lock);

+}

+static void panfrost_gem_debugfs_bo_rm(struct panfrost_gem_object *bo) +{

• struct panfrost_device *pfdev = bo->base.base.dev->dev_private;
• if (list_empty(&bo->debugfs.node))

• return;
  

• mutex_lock(&pfdev->debugfs.gems_lock);
• list_del_init(&bo->debugfs.node);
• mutex_unlock(&pfdev->debugfs.gems_lock);

+} +#else +static void panfrost_gem_debugfs_bo_add(struct panfrost_device *pfdev,

• 			struct panfrost_gem_object *bo)
  

+{} +static void panfrost_gem_debugfs_bo_rm(struct panfrost_gem_object *bo) {} +#endif

/* Called DRM core on the last userspace/kernel unreference of the

• BO.

*/ @@ -37,6 +67,7 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj) WARN_ON_ONCE(!list_empty(&bo->mappings.list)); kfree_const(bo->label.str);

• panfrost_gem_debugfs_bo_rm(bo); mutex_destroy(&bo->label.lock);

if (bo->sgts) { @@ -266,6 +297,8 @@ struct drm_gem_object *panfrost_gem_create_object(struct drm_device *dev, size_t obj->base.map_wc = !pfdev->coherent; mutex_init(&obj->label.lock);

• panfrost_gem_debugfs_bo_add(pfdev, obj);
• return &obj->base.base;

} @@ -354,3 +387,104 @@ panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label) panfrost_gem_set_label(obj, str); }

+#ifdef CONFIG_DEBUG_FS +struct gem_size_totals {

• size_t size;
• size_t resident;
• size_t reclaimable;

+};

+struct flag_def {

• u32 flag;
• const char *name;

+};

+static void panfrost_gem_debugfs_print_flag_names(struct seq_file *m) +{

• int len;
• int i;
• static const struct flag_def gem_state_flags_names[] = {

• {PANFROST_DEBUGFS_GEM_STATE_FLAG_IMPORTED, "imported"},
  

• {PANFROST_DEBUGFS_GEM_STATE_FLAG_EXPORTED, "exported"},
  

• {PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGED, "purged"},
  

• {PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGEABLE, "purgeable"},
  

• };
• seq_puts(m, "GEM state flags: ");
• for (i = 0, len = ARRAY_SIZE(gem_state_flags_names); i < len; i++) {

• seq_printf(m, "%s (0x%x)%s", gem_state_flags_names[i].name,
  

• 	   gem_state_flags_names[i].flag, (i < len - 1) ? ", " : "\n\n");
  

• }

+}

+static void panfrost_gem_debugfs_bo_print(struct panfrost_gem_object *bo,

• 			  struct seq_file *m,
  

• 			  struct gem_size_totals *totals)
  

+{

• unsigned int refcount = kref_read(&bo->base.base.refcount);
• char creator_info[32] = {};
• size_t resident_size;
• u32 gem_state_flags = 0;
• /* Skip BOs being destroyed. */
• if (!refcount)

• return;
  

• resident_size = bo->base.pages ? bo->base.base.size : 0;
• snprintf(creator_info, sizeof(creator_info),

•  "%s/%d", bo->debugfs.creator.process_name, bo->debugfs.creator.tgid);
  

• seq_printf(m, "%-32s%-16d%-16d%-16zd%-16zd0x%-16lx",

•    creator_info,
  

•    bo->base.base.name,
  

•    refcount,
  

•    bo->base.base.size,
  

•    resident_size,
  

•    drm_vma_node_start(&bo->base.base.vma_node));
  

• if (bo->base.base.import_attach)

• gem_state_flags |= PANFROST_DEBUGFS_GEM_STATE_FLAG_IMPORTED;
  

• if (bo->base.base.dma_buf)

• gem_state_flags |= PANFROST_DEBUGFS_GEM_STATE_FLAG_EXPORTED;
  

• if (bo->base.madv < 0)

• gem_state_flags |= PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGED;
  

• else if (bo->base.madv > 0)

• gem_state_flags |= PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGEABLE;
  

• seq_printf(m, "0x%-10x", gem_state_flags);
• scoped_guard(mutex, &bo->label.lock) {

• seq_printf(m, "%s\n", bo->label.str ? : "");
  

• }
• totals->size += bo->base.base.size;
• totals->resident += resident_size;
• if (bo->base.madv > 0)

• totals->reclaimable += resident_size;
  

+}

+void panfrost_gem_debugfs_print_bos(struct panfrost_device *pfdev,

• 		    struct seq_file *m)
  

+{

• struct gem_size_totals totals = {0};
• struct panfrost_gem_object *bo;
• panfrost_gem_debugfs_print_flag_names(m);
• seq_puts(m, "created-by global-name refcount size resident-size file-offset state label\n");
• seq_puts(m, "-----------------------------------------------------------------------------------------------------------------------------------\n");
• scoped_guard(mutex, &pfdev->debugfs.gems_lock) {

• list_for_each_entry(bo, &pfdev->debugfs.gems_list, debugfs.node) {
  

• 	panfrost_gem_debugfs_bo_print(bo, m, &totals);
  

• }
  

• }
• seq_puts(m, "===================================================================================================================================\n");
• seq_printf(m, "Total size: %zd, Total resident: %zd, Total reclaimable: %zd\n",

•    totals.size, totals.resident, totals.reclaimable);
  

+} +#endif diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index 3d87c41ad09d..8de3e76f2717 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -8,9 +8,47 @@ #include <drm/drm_mm.h> struct panfrost_mmu; +struct panfrost_device; #define PANFROST_BO_LABEL_MAXLEN 4096 +enum panfrost_debugfs_gem_state_flags {

• /** @PANFROST_DEBUGFS_GEM_STATE_FLAG_IMPORTED: GEM BO is PRIME imported. */
• PANFROST_DEBUGFS_GEM_STATE_FLAG_IMPORTED = BIT(0),
• /** @PANFROST_DEBUGFS_GEM_STATE_FLAG_EXPORTED: GEM BO is PRIME exported. */
• PANFROST_DEBUGFS_GEM_STATE_FLAG_EXPORTED = BIT(1),
• /** @PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGED: GEM BO was reclaimed by the shrinker. */
• PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGED = BIT(2),
• /**

• * @PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGEABLE: GEM BO pages were marked as no longer
  

• * needed by UM and can be reclaimed by the shrinker.
  

• */
  

• PANFROST_DEBUGFS_GEM_STATE_FLAG_PURGEABLE = BIT(3),

+};

+/**

• • struct panfrost_gem_debugfs - GEM object's DebugFS list information
• */

+struct panfrost_gem_debugfs {

• /**

• * @node: Node used to insert the object in the device-wide list of
  

• * GEM objects, to display information about it through a DebugFS file.
  

• */
  

• struct list_head node;
• /** @creator: Information about the UM process which created the GEM. */
• struct {

• /** @creator.process_name: Group leader name in owning thread's process */
  

• char process_name[TASK_COMM_LEN];
  

• /** @creator.tgid: PID of the thread's group leader within its process */
  

• pid_t tgid;
  

• } creator;

+};

struct panfrost_gem_object { struct drm_gem_shmem_object base; struct sg_table *sgts; @@ -59,6 +97,10 @@ struct panfrost_gem_object { bool noexec :1; bool is_heap :1;

+#ifdef CONFIG_DEBUG_FS

• struct panfrost_gem_debugfs debugfs;

+#endif }; struct panfrost_gem_mapping { @@ -108,4 +150,9 @@ void panfrost_gem_shrinker_cleanup(struct drm_device *dev); void panfrost_gem_set_label(struct drm_gem_object *obj, const char *label); void panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char *label); +#ifdef CONFIG_DEBUG_FS +void panfrost_gem_debugfs_print_bos(struct panfrost_device *pfdev,

• 		    struct seq_file *m);
  

+#endif

#endif /* __PANFROST_GEM_H__ */