[PATCH v4 5/6] drm: Add fdinfo memory stats

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

Add support to dump GEM stats to fdinfo.

v2: Fix typos, change size units to match docs, use div_u64
v3: Do it in core
v4: more kerneldoc

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 Documentation/gpu/drm-usage-stats.rst | 21 ++++++++
 drivers/gpu/drm/drm_file.c            | 76 +++++++++++++++++++++++++++
 include/drm/drm_file.h                |  1 +
 include/drm/drm_gem.h                 | 30 +++++++++++
 4 files changed, 128 insertions(+)

diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
index 2ab32c40e93c..80003e27e28e 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -105,6 +105,27 @@ object belong to this client, in the respective memory region.
 Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB'
 indicating kibi- or mebi-bytes.
 
+- drm-shared-memory: <uint> [KiB|MiB]
+
+The total size of buffers that are shared with another file (ie. have more
+than a single handle).
+
+- drm-private-memory: <uint> [KiB|MiB]
+
+The total size of buffers that are not shared with another file.
+
+- drm-resident-memory: <uint> [KiB|MiB]
+
+The total size of buffers that are resident in system memory.
+
+- drm-purgeable-memory: <uint> [KiB|MiB]
+
+The total size of buffers that are purgeable.
+
+- drm-active-memory: <uint> [KiB|MiB]
+
+The total size of buffers that are active on one or more rings.
+
 - drm-cycles-<str> <uint>
 
 Engine identifier string must be the same as the one specified in the
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 6d5bdd684ae2..04a7ed7eba8e 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -42,6 +42,7 @@
 #include <drm/drm_client.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
+#include <drm/drm_gem.h>
 #include <drm/drm_print.h>
 
 #include "drm_crtc_internal.h"
@@ -871,6 +872,79 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
 }
 EXPORT_SYMBOL(drm_send_event);
 
+static void print_size(struct drm_printer *p, const char *stat, size_t sz)
+{
+	const char *units[] = {"", " KiB", " MiB"};
+	unsigned u;
+
+	for (u = 0; u < ARRAY_SIZE(units) - 1; u++) {
+		if (sz < SZ_1K)
+			break;
+		sz = div_u64(sz, SZ_1K);
+	}
+
+	drm_printf(p, "%s:\t%zu%s\n", stat, sz, units[u]);
+}
+
+static void print_memory_stats(struct drm_printer *p, struct drm_file *file)
+{
+	struct drm_gem_object *obj;
+	struct {
+		size_t shared;
+		size_t private;
+		size_t resident;
+		size_t purgeable;
+		size_t active;
+	} size = {0};
+	bool has_status = false;
+	int id;
+
+	spin_lock(&file->table_lock);
+	idr_for_each_entry (&file->object_idr, obj, id) {
+		enum drm_gem_object_status s = 0;
+
+		if (obj->funcs && obj->funcs->status) {
+			s = obj->funcs->status(obj);
+			has_status = true;
+		}
+
+		if (obj->handle_count > 1) {
+			size.shared += obj->size;
+		} else {
+			size.private += obj->size;
+		}
+
+		if (s & DRM_GEM_OBJECT_RESIDENT) {
+			size.resident += obj->size;
+		} else {
+			/* If already purged or not yet backed by pages, don't
+			 * count it as purgeable:
+			 */
+			s &= ~DRM_GEM_OBJECT_PURGEABLE;
+		}
+
+		if (!dma_resv_test_signaled(obj->resv, dma_resv_usage_rw(true))) {
+			size.active += obj->size;
+
+			/* If still active, don't count as purgeable: */
+			s &= ~DRM_GEM_OBJECT_PURGEABLE;
+		}
+
+		if (s & DRM_GEM_OBJECT_PURGEABLE)
+			size.purgeable += obj->size;
+	}
+	spin_unlock(&file->table_lock);
+
+	print_size(p, "drm-shared-memory", size.shared);
+	print_size(p, "drm-private-memory", size.private);
+	print_size(p, "drm-active-memory", size.active);
+
+	if (has_status) {
+		print_size(p, "drm-resident-memory", size.resident);
+		print_size(p, "drm-purgeable-memory", size.purgeable);
+	}
+}
+
 /**
  * drm_show_fdinfo - helper for drm file fops
  * @seq_file: output stream
@@ -900,6 +974,8 @@ void drm_show_fdinfo(struct seq_file *m, struct file *f)
 
 	if (dev->driver->show_fdinfo)
 		dev->driver->show_fdinfo(&p, file);
+
+	print_memory_stats(&p, file);
 }
 EXPORT_SYMBOL(drm_show_fdinfo);
 
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 6de6d0e9c634..919284bb4f1d 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -41,6 +41,7 @@
 struct dma_fence;
 struct drm_file;
 struct drm_device;
+struct drm_printer;
 struct device;
 struct file;
 
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 189fd618ca65..9ebd2820ad1f 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -42,6 +42,25 @@
 struct iosys_map;
 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
+ *
+ * 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
+ * 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.)
+ */
+enum drm_gem_object_status {
+	DRM_GEM_OBJECT_RESIDENT  = BIT(0),
+	DRM_GEM_OBJECT_PURGEABLE = BIT(1),
+};
+
 /**
  * struct drm_gem_object_funcs - GEM object functions
  */
@@ -174,6 +193,17 @@ struct drm_gem_object_funcs {
 	 */
 	int (*evict)(struct drm_gem_object *obj);
 
+	/**
+	 * @status:
+	 *
+	 * The optional status callback can return additional object state
+	 * which determines which stats the object is counted against.  The
+	 * callback is called under table_lock.  Racing against object status
+	 * change is "harmless", and the callback can expect to not race
+	 * against object destruction.
+	 */
+	enum drm_gem_object_status (*status)(struct drm_gem_object *obj);
+
 	/**
 	 * @vm_ops:
 	 *
-- 
2.39.2