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Message-ID: <20250317092614.55b3c4e9@collabora.com>
Date: Mon, 17 Mar 2025 09:26:14 +0100
From: Boris Brezillon <boris.brezillon@...labora.com>
To: Adrián Larumbe <adrian.larumbe@...labora.com>
Cc: Steven Price <steven.price@....com>, Liviu Dudau <liviu.dudau@....com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
<mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, David Airlie
<airlied@...il.com>, Simona Vetter <simona@...ll.ch>, Sumit Semwal
<sumit.semwal@...aro.org>, Christian König
<christian.koenig@....com>, kernel@...labora.com,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org, linaro-mm-sig@...ts.linaro.org
Subject: Re: [PATCH 3/4] drm/panthor: show device-wide list of DRM GEM
objects over DebugFS
On Sun, 16 Mar 2025 21:51:34 +0000
Adrián Larumbe <adrian.larumbe@...labora.com> wrote:
> Add a device DebugFS file that displays a complete list of all the DRM GEM
> objects that are exposed to UM through a DRM handle.
>
> Since leaking object identifiers that might belong to a different NS is
> inadmissible, this functionality is only made available in debug builds
> with DEBUGFS support enabled.
>
> File format is that of a table, with each entry displaying a variety of
> fields with information about each GEM object.
>
> Each GEM object entry in the file displays the following information
> fields: Client PID, BO's global name, reference count, BO virtual size, BO
> resize size, VM address in its DRM-managed range, BO label and a flag
> bitmask.
>
> Signed-off-by: Adrián Larumbe <adrian.larumbe@...labora.com>
> ---
> drivers/gpu/drm/panthor/panthor_device.c | 5 ++
> drivers/gpu/drm/panthor/panthor_device.h | 8 ++
> drivers/gpu/drm/panthor/panthor_drv.c | 26 ++++++
> drivers/gpu/drm/panthor/panthor_gem.c | 101 +++++++++++++++++++++++
> drivers/gpu/drm/panthor/panthor_gem.h | 22 +++++
> 5 files changed, 162 insertions(+)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> index a9da1d1eeb70..7df12eefc39f 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -263,6 +263,11 @@ int panthor_device_init(struct panthor_device *ptdev)
> pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50);
> pm_runtime_use_autosuspend(ptdev->base.dev);
>
> +#ifdef CONFIG_DEBUG_FS
> + drmm_mutex_init(&ptdev->base, &ptdev->gems_lock);
> + INIT_LIST_HEAD(&ptdev->gems);
> +#endif
> +
> ret = drm_dev_register(&ptdev->base, 0);
> if (ret)
> goto err_disable_autosuspend;
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
> index da6574021664..6c030978cdc3 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -205,6 +205,14 @@ struct panthor_device {
>
> /** @fast_rate: Maximum device clock frequency. Set by DVFS */
> unsigned long fast_rate;
> +
> +#ifdef CONFIG_DEBUG_FS
> + /** @gems_lock: Protects the device-wide list of GEM objects. */
> + struct mutex gems_lock;
> +
> + /** @gems: Device-wide list of GEM objects owned by at least one file. */
> + struct list_head gems;
struct {
struct mutex lock;
struct list_head list;
} gems;
> +#endif
> };
>
> struct panthor_gpu_usage {
> diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
> index f41b8946258f..6663eff44bdc 100644
> --- a/drivers/gpu/drm/panthor/panthor_drv.c
> +++ b/drivers/gpu/drm/panthor/panthor_drv.c
> @@ -1525,9 +1525,35 @@ static const struct file_operations panthor_drm_driver_fops = {
> };
>
> #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 panthor_device *ptdev = container_of(dev, struct panthor_device, base);
> +
> + panthor_gem_print_objects(ptdev, 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 panthor_debugfs_init(struct drm_minor *minor)
> {
> panthor_mmu_debugfs_init(minor);
> + panthor_gems_debugfs_init(minor);
> }
> #endif
>
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c
> index 3c58bb2965ea..8cea6caf3143 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.c
> +++ b/drivers/gpu/drm/panthor/panthor_gem.c
> @@ -17,6 +17,16 @@ static void panthor_gem_free_object(struct drm_gem_object *obj)
> {
> struct panthor_gem_object *bo = to_panthor_bo(obj);
> struct drm_gem_object *vm_root_gem = bo->exclusive_vm_root_gem;
> +#ifdef CONFIG_DEBUG_FS
> + struct drm_device *dev = bo->base.base.dev;
> + struct panthor_device *ptdev = container_of(dev, struct panthor_device, base);
> +
> + if (!list_empty(&bo->gems_node)) {
> + mutex_lock(&ptdev->gems_lock);
> + list_del_init(&bo->gems_node);
> + mutex_unlock(&ptdev->gems_lock);
> + }
> +#endif
Can we add helpers to add/remove a GEM to the list and define dummy
implementations for the !CONFIG_DEBUG_FS case?
#ifdef CONFIG_DEBUG_FS
static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo)
{
INIT_LIST_HEAD(&obj->gems_node);
obj->creator.tgid = current->group_leader->pid;
get_task_comm(obj->creator.process_name, current->group_leader);
}
static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo)
{
struct panthor_device *ptdev = container_of(bo->base.base.dev,
struct panthor_device, base);
mutex_lock(&ptdev->gems_lock);
list_add_tail(&bo->gems_node, &ptdev->gems);
mutex_unlock(&ptdev->gems_lock);
}
static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo)
{
struct panthor_device *ptdev = container_of(bo->base.base.dev,
struct panthor_device, base);
if (list_empty(&bo->gems_node))
return;
mutex_lock(&ptdev->gems_lock);
list_del_init(&bo->gems_node);
mutex_unlock(&ptdev->gems_lock);
}
#else
static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo) {}
static void panthor_gem_debugfs_bo_add(struct panthor_gem_object *bo) {}
static void panthor_gem_debugfs_bo_rm(struct panthor_gem_object *bo) {}
#endif
>
> kfree(bo->label);
> mutex_destroy(&bo->label_lock);
> @@ -201,6 +211,12 @@ struct drm_gem_object *panthor_gem_create_object(struct drm_device *ddev, size_t
> drm_gem_gpuva_set_lock(&obj->base.base, &obj->gpuva_list_lock);
> mutex_init(&obj->label_lock);
>
> +#ifdef CONFIG_DEBUG_FS
> + INIT_LIST_HEAD(&obj->gems_node);
> + obj->creator.tgid = current->group_leader->pid;
> + get_task_comm(obj->creator.process_name, current->group_leader);
> +#endif
panthor_gem_debugfs_bo_init(obj);
> +
> return &obj->base.base;
> }
>
> @@ -224,6 +240,10 @@ panthor_gem_create_with_handle(struct drm_file *file,
> int ret;
> struct drm_gem_shmem_object *shmem;
> struct panthor_gem_object *bo;
> +#ifdef CONFIG_DEBUG_FS
> + struct panthor_device *ptdev =
> + container_of(ddev, struct panthor_device, base);
> +#endif
>
> shmem = drm_gem_shmem_create(ddev, *size);
> if (IS_ERR(shmem))
> @@ -249,6 +269,12 @@ panthor_gem_create_with_handle(struct drm_file *file,
> /* drop reference from allocate - handle holds it now. */
> drm_gem_object_put(&shmem->base);
>
> +#ifdef CONFIG_DEBUG_FS
> + mutex_lock(&ptdev->gems_lock);
> + list_add_tail(&bo->gems_node, &ptdev->gems);
> + mutex_unlock(&ptdev->gems_lock);
> +#endif
panthor_gem_debugfs_bo_rm(bo);
> +
> return ret;
> }
>
> @@ -265,3 +291,78 @@ panthor_gem_label_bo(struct drm_gem_object *obj, const char *label)
>
> kfree(old_label);
> }
> +
> +#ifdef CONFIG_DEBUG_FS
> +static bool panfrost_gem_print_flag(const char *name,
> + bool is_set,
> + bool other_flags_printed,
> + struct seq_file *m)
> +{
> + if (is_set)
> + seq_printf(m, "%s%s", other_flags_printed ? "," : "", name);
> +
> + return is_set | other_flags_printed;
> +}
> +
> +void panthor_gem_print_objects(struct panthor_device *ptdev,
> + struct seq_file *m)
> +{
> + size_t total = 0, total_resident = 0, total_reclaimable = 0;
> + struct panthor_gem_object *bo;
> +
> + seq_puts(m, "created-by global-name refcount size resident-size file-offset flags label\n");
> + seq_puts(m, "------------------------------------------------------------------------------------------------------------------------------------------------\n");
> +
> + mutex_lock(&ptdev->gems_lock);
> + list_for_each_entry(bo, &ptdev->gems, gems_node) {
> + unsigned int refcount = kref_read(&bo->base.base.refcount);
> + char creator_info[32] = {};
> + bool has_flags = false;
> + size_t resident_size;
> +
> + /* Skip BOs being destroyed. */
> + if (!refcount)
> + continue;
> +
> + resident_size = bo->base.pages != NULL ? bo->base.base.size : 0;
> +
> + snprintf(creator_info, sizeof(creator_info),
> + "%s/%d", bo->creator.process_name, bo->creator.tgid);
> + seq_printf(m, "%-32s%-16d%-16d%-16zd%-16zd%-16lx",
> + creator_info,
> + bo->base.base.name,
> + refcount,
> + bo->base.base.size,
> + resident_size,
> + drm_vma_node_start(&bo->base.base.vma_node));
> +
> + seq_puts(m, "(");
> + has_flags = panfrost_gem_print_flag("imported", bo->base.base.import_attach != NULL,
> + has_flags, m);
> + has_flags = panfrost_gem_print_flag("exported", bo->base.base.dma_buf != NULL,
> + has_flags, m);
> + if (bo->base.madv < 0)
> + has_flags = panfrost_gem_print_flag("purged", true, has_flags, m);
> + else if (bo->base.madv > 0)
> + has_flags = panfrost_gem_print_flag("purgeable", true, has_flags, m);
> + if (!has_flags)
> + seq_puts(m, "none");
> + seq_puts(m, ")");
> +
> + mutex_lock(&bo->label_lock);
> + seq_printf(m, "%-16s%-60s", "", bo->label ? : NULL);
> + mutex_unlock(&bo->label_lock);
> + seq_puts(m, "\n");
Let's have a panthor_gem_debugfs_bo_print() helper to print a single BO.
> +
> + total += bo->base.base.size;
> + total_resident += resident_size;
> + if (bo->base.madv > 0)
> + total_reclaimable += resident_size;
> + }
> + mutex_unlock(&ptdev->gems_lock);
> +
> + seq_puts(m, "================================================================================================================================================\n");
> + seq_printf(m, "Total size: %zd, Total resident: %zd, Total reclaimable: %zd\n",
> + total, total_resident, total_reclaimable);
> +}
> +#endif
> diff --git a/drivers/gpu/drm/panthor/panthor_gem.h b/drivers/gpu/drm/panthor/panthor_gem.h
> index da9268d24566..c0be30434b34 100644
> --- a/drivers/gpu/drm/panthor/panthor_gem.h
> +++ b/drivers/gpu/drm/panthor/panthor_gem.h
> @@ -55,6 +55,23 @@ struct panthor_gem_object {
>
> /** @label_lock: Lock that protects access to the @label field. */
> struct mutex label_lock;
> +
> +#ifdef CONFIG_DEBUG_FS
> + /**
> + * @gems_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 gems_node;
> +
> + /** @creator: Information about the UM process which created the GEM. */
> + struct {
> + /** @process_name: Group leader name in owning thread's process */
> + char process_name[TASK_COMM_LEN];
> +
> + /** @tgid: PID of the thread's group leader within its process */
> + pid_t tgid;
> + } creator;
Can we put all these fields under a debugfs struct?
struct panthor_gem_debugfs {
/**
* @gems_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 gems_node;
/** @creator: Information about the UM process which created the GEM. */
struct {
/** @process_name: Group leader name in owning thread's process */
char process_name[TASK_COMM_LEN];
/** @tgid: PID of the thread's group leader within its process */
pid_t tgid;
} creator;
};
...
struct panthor_gem_object {
...
#ifdef CONFIG_DEBUG_FS
struct panthor_gem_debugfs debugfs;
#endif
...
};
> +#endif
> };
>
> /**
> @@ -150,4 +167,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
>
> void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo);
>
> +#ifdef CONFIG_DEBUG_FS
> +void panthor_gem_print_objects(struct panthor_device *pfdev,
> + struct seq_file *m);
s/panthor_gem_print_objects/panthor_gem_debugfs_print_bos/
> +#endif
> +
> #endif /* __PANTHOR_GEM_H__ */
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