[PATCH v2 5/9] drm: Add fdinfo memory stats

Rob Clark
2023-04-27T17:54:30Z

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 | 54 +++++++++++----
drivers/gpu/drm/drm_file.c | 99 ++++++++++++++++++++++++++-
include/drm/drm_file.h | 19 +++++
include/drm/drm_gem.h | 30 ++++++++
4 files changed, 189 insertions(+), 13 deletions(-)

diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
index 552195fb1ea3..bfc14150452c 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -52,6 +52,9 @@ String shall contain the name this driver registered as via the respective
Optional fully standardised keys
--------------------------------

+Identification
+^^^^^^^^^^^^^^
+
- drm-pdev: <aaaa:bb.cc.d>

For PCI devices this should contain the PCI slot address of the device in
@@ -69,6 +72,9 @@ scope of each device, in which case `drm-pdev` shall be present as well.
Userspace should make sure to not double account any usage statistics by using
the above described criteria in order to associate data to individual clients.

+Utilization
+^^^^^^^^^^^
+
- drm-engine-<str>: <uint> ns

GPUs usually contain multiple execution engines. Each shall be given a stable
@@ -93,18 +99,6 @@ exported engine corresponds to a group of identical hardware engines.
In the absence of this tag parser shall assume capacity of one. Zero capacity
is not allowed.

-- drm-memory-<str>: <uint> [KiB|MiB]
-
-Each possible memory type which can be used to store buffer objects by the
-GPU in question shall be given a stable and unique name to be returned as the
-string here.
-
-Value shall reflect the amount of storage currently consumed by the buffer
-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-cycles-<str>: <uint>

Engine identifier string must be the same as the one specified in the
@@ -126,6 +120,42 @@ percentage utilization of the engine, whereas drm-engine-<str> only reflects
time active without considering what frequency the engine is operating as a
percentage of it's maximum frequency.

+Memory
+^^^^^^
+
+- drm-memory-<region>: <uint> [KiB|MiB]
+
+Each possible memory type which can be used to store buffer objects by the
+GPU in question shall be given a stable and unique name to be returned as the
+string here. The name "memory" is reserved to refer to normal system memory.
+
+Value shall reflect the amount of storage currently consumed by the buffer
+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-<region>: <uint> [KiB|MiB]
+
+The total size of buffers that are shared with another file (ie. have more
+than a single handle).
+
+- drm-private-<region>: <uint> [KiB|MiB]
+
+The total size of buffers that are not shared with another file.
+
+- drm-resident-<region>: <uint> [KiB|MiB]
+
+The total size of buffers that are resident in system memory.
+
+- drm-purgeable-<region>: <uint> [KiB|MiB]
+
+The total size of buffers that are purgeable.
+
+- drm-active-<region>: <uint> [KiB|MiB]
+
+The total size of buffers that are active on one or more rings.
+
Implementation Details
======================

diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 6d5bdd684ae2..9321eb0bf020 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"
@@ -871,9 +872,105 @@ 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,
+ const char *region, 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, "drm-%s-%s:\t%zu%s\n", stat, region, sz, units[u]);
+}
+
+/**
+ * drm_print_memory_stats - A helper to print memory stats
+ * @p: The printer to print output to
+ * @stats: The collected memory stats
+ * @supported_status: Bitmask of optional stats which are available
+ * @region: The memory region
+ *
+ */
+void drm_print_memory_stats(struct drm_printer *p,
+ const struct drm_memory_stats *stats,
+ enum drm_gem_object_status supported_status,
+ const char *region)
+{
+ print_size(p, "total", region, stats->private + stats->shared);
+ print_size(p, "shared", region, stats->shared);
+ print_size(p, "active", region, stats->active);
+
+ if (supported_status & DRM_GEM_OBJECT_RESIDENT)
+ print_size(p, "resident", region, stats->resident);
+
+ if (supported_status & DRM_GEM_OBJECT_PURGEABLE)
+ print_size(p, "purgeable", region, stats->purgeable);
+}
+EXPORT_SYMBOL(drm_print_memory_stats);
+
+/**
+ * drm_show_memory_stats - Helper to collect and show standard fdinfo memory stats
+ * @p: the printer to print output to
+ * @file: the DRM file
+ *
+ * Helper to iterate over GEM objects with a handle allocated in the specified
+ * file.
+ */
+void drm_show_memory_stats(struct drm_printer *p, struct drm_file *file)
+{
+ struct drm_gem_object *obj;
+ struct drm_memory_stats status = {};
+ enum drm_gem_object_status supported_status;
+ 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);
+ supported_status = DRM_GEM_OBJECT_RESIDENT |
+ DRM_GEM_OBJECT_PURGEABLE;
+ }
+
+ if (obj->handle_count > 1) {
+ status.shared += obj->size;
+ } else {
+ status.private += obj->size;
+ }
+
+ if (s & DRM_GEM_OBJECT_RESIDENT) {
+ status.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))) {
+ status.active += obj->size;
+
+ /* If still active, don't count as purgeable: */
+ s &= ~DRM_GEM_OBJECT_PURGEABLE;
+ }
+
+ if (s & DRM_GEM_OBJECT_PURGEABLE)
+ status.purgeable += obj->size;
+ }
+ spin_unlock(&file->table_lock);
+
+ drm_print_memory_stats(p, &status, supported_status, "memory");
+}
+EXPORT_SYMBOL(drm_show_memory_stats);
+
/**
* drm_show_fdinfo - helper for drm file fops
- * @seq_file: output stream
+ * @m: output stream
* @f: the device file instance
*
* Helper to implement fdinfo, for userspace to query usage stats, etc, of a
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 6de6d0e9c634..1339e925af52 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;

@@ -440,6 +441,24 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e);
void drm_send_event_timestamp_locked(struct drm_device *dev,
struct drm_pending_event *e,
ktime_t timestamp);
+
+
+struct drm_memory_stats {
+ size_t shared;
+ size_t private;
+ size_t resident;
+ size_t purgeable;
+ size_t active;
+};
+
+enum drm_gem_object_status;
+
+void drm_print_memory_stats(struct drm_printer *p,
+ const struct drm_memory_stats *stats,
+ enum drm_gem_object_status supported_status,
+ const char *region);
+
+void drm_show_memory_stats(struct drm_printer *p, struct drm_file *file);
void drm_show_fdinfo(struct seq_file *m, struct file *f);

struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags);
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