[Intel-gfx] [PATCH 1/7] drm/i915: Explicitly track DRM clients

Tvrtko Ursulin
2021-09-22T15:52:02Z

Tracking DRM clients more explicitly will allow later patches to
accumulate past and current GPU usage in a centralised place and also
consolidate access to owning task pid/name.

Unique client id is also assigned for the purpose of distinguishing/
consolidating between multiple file descriptors owned by the same process.

v2:
Chris Wilson:
* Enclose new members into dedicated structs.
* Protect against failed sysfs registration.

v3:
* sysfs_attr_init.

v4:
* Fix for internal clients.

v5:
* Use cyclic ida for client id. (Chris)
* Do not leak pid reference. (Chris)
* Tidy code with some locals.

v6:
* Use xa_alloc_cyclic to simplify locking. (Chris)
* No need to unregister individial sysfs files. (Chris)
* Rebase on top of fpriv kref.
* Track client closed status and reflect in sysfs.

v7:
* Make drm_client more standalone concept.

v8:
* Simplify sysfs show. (Chris)
* Always track name and pid.

v9:
* Fix cyclic id assignment.

v10:
* No need for a mutex around xa_alloc_cyclic.
* Refactor sysfs into own function.
* Unregister sysfs before freeing pid and name.
* Move clients setup into own function.

v11:
* Call clients init directly from driver init. (Chris)

v12:
* Do not fail client add on id wrap. (Maciej)

v13 (Lucas): Rebase.

v14:
* Dropped sysfs bits.

v15:
* Dropped tracking of pid/ and name.
* Dropped RCU freeing of the client object.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v11
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com> # v11
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/Makefile | 5 +-
drivers/gpu/drm/i915/i915_drm_client.c | 68 ++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_drm_client.h | 50 +++++++++++++++++++
drivers/gpu/drm/i915/i915_drv.c | 6 +++
drivers/gpu/drm/i915/i915_drv.h | 5 ++
drivers/gpu/drm/i915/i915_gem.c | 21 ++++++--
6 files changed, 150 insertions(+), 5 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_drm_client.c
create mode 100644 drivers/gpu/drm/i915/i915_drm_client.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 335a8c668848..8187c9e52a79 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -32,8 +32,9 @@ subdir-ccflags-y += -I$(srctree)/$(src)
# Please keep these build lists sorted!

# core driver code
-i915-y += i915_drv.o \
- i915_config.o \
+i915-y += i915_config.o \
+ i915_drm_client.o \
+ i915_drv.o \
i915_irq.o \
i915_getparam.o \
i915_mitigations.o \
diff --git a/drivers/gpu/drm/i915/i915_drm_client.c b/drivers/gpu/drm/i915/i915_drm_client.c
new file mode 100644
index 000000000000..e61e9ba15256
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_drm_client.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "i915_drm_client.h"
+#include "i915_gem.h"
+#include "i915_utils.h"
+
+void i915_drm_clients_init(struct i915_drm_clients *clients,
+ struct drm_i915_private *i915)
+{
+ clients->i915 = i915;
+ clients->next_id = 0;
+
+ xa_init_flags(&clients->xarray, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_IRQ);
+}
+
+struct i915_drm_client *i915_drm_client_add(struct i915_drm_clients *clients)
+{
+ struct i915_drm_client *client;
+ struct xarray *xa = &clients->xarray;
+ int ret;
+
+ client = kzalloc(sizeof(*client), GFP_KERNEL);
+ if (!client)
+ return ERR_PTR(-ENOMEM);
+
+ xa_lock_irq(xa);
+ ret = __xa_alloc_cyclic(xa, &client->id, client, xa_limit_32b,
+ &clients->next_id, GFP_KERNEL);
+ xa_unlock_irq(xa);
+ if (ret < 0)
+ goto err;
+
+ kref_init(&client->kref);
+ client->clients = clients;
+
+ return client;
+
+err:
+ kfree(client);
+
+ return ERR_PTR(ret);
+}
+
+void __i915_drm_client_free(struct kref *kref)
+{
+ struct i915_drm_client *client =
+ container_of(kref, typeof(*client), kref);
+ struct xarray *xa = &client->clients->xarray;
+ unsigned long flags;
+
+ xa_lock_irqsave(xa, flags);
+ __xa_erase(xa, client->id);
+ xa_unlock_irqrestore(xa, flags);
+ kfree(client);
+}
+
+void i915_drm_clients_fini(struct i915_drm_clients *clients)
+{
+ GEM_BUG_ON(!xa_empty(&clients->xarray));
+ xa_destroy(&clients->xarray);
+}
diff --git a/drivers/gpu/drm/i915/i915_drm_client.h b/drivers/gpu/drm/i915/i915_drm_client.h
new file mode 100644
index 000000000000..e8986ad51176
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_drm_client.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#ifndef __I915_DRM_CLIENT_H__
+#define __I915_DRM_CLIENT_H__
+
+#include <linux/kref.h>
+#include <linux/xarray.h>
+
+struct drm_i915_private;
+
+struct i915_drm_clients {
+ struct drm_i915_private *i915;
+
+ struct xarray xarray;
+ u32 next_id;
+};
+
+struct i915_drm_client {
+ struct kref kref;
+
+ unsigned int id;
+
+ struct i915_drm_clients *clients;
+};
+
+void i915_drm_clients_init(struct i915_drm_clients *clients,
+ struct drm_i915_private *i915);
+
+static inline struct i915_drm_client *
+i915_drm_client_get(struct i915_drm_client *client)
+{
+ kref_get(&client->kref);
+ return client;
+}
+
+void __i915_drm_client_free(struct kref *kref);
+
+static inline void i915_drm_client_put(struct i915_drm_client *client)
+{
+ kref_put(&client->kref, __i915_drm_client_free);
+}
+
+struct i915_drm_client *i915_drm_client_add(struct i915_drm_clients *clients);
+
+void i915_drm_clients_fini(struct i915_drm_clients *clients);
+
+#endif /* !__I915_DRM_CLIENT_H__ */
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3cf61bead2f6..6418f3dbdad0 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -68,6 +68,7 @@
#include "gt/intel_rc6.h"

#include "i915_debugfs.h"
+#include "i915_drm_client.h"
#include "i915_drv.h"
#include "i915_ioc32.h"
#include "i915_irq.h"
@@ -344,6 +345,8 @@ static int i915_driver_early_probe(struct drm_i915_private *dev_priv)

intel_gt_init_early(&dev_priv->gt, dev_priv);

+ i915_drm_clients_init(&dev_priv->clients, dev_priv);
+
i915_gem_init_early(dev_priv);

/* This must be called before any calls to HAS_PCH_* */
@@ -363,6 +366,7 @@ static int i915_driver_early_probe(struct drm_i915_private *dev_priv)

err_gem:
i915_gem_cleanup_early(dev_priv);
+ i915_drm_clients_fini(&dev_priv->clients);
intel_gt_driver_late_release(&dev_priv->gt);
intel_region_ttm_device_fini(dev_priv);
err_ttm:
@@ -382,6 +386,7 @@ static void i915_driver_late_release(struct drm_i915_private *dev_priv)
intel_irq_fini(dev_priv);
intel_power_domains_cleanup(dev_priv);
i915_gem_cleanup_early(dev_priv);
+ i915_drm_clients_fini(&dev_priv->clients);
intel_gt_driver_late_release(&dev_priv->gt);
intel_region_ttm_device_fini(dev_priv);
vlv_suspend_cleanup(dev_priv);
@@ -997,6 +1002,7 @@ static void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
struct drm_i915_file_private *file_priv = file->driver_priv;

i915_gem_context_close(file);
+ i915_drm_client_put(file_priv->client);

kfree_rcu(file_priv, rcu);

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cc355aa05dbf..2078e4776cdc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -96,6 +96,7 @@
#include "intel_wakeref.h"
#include "intel_wopcm.h"

+#include "i915_drm_client.h"
#include "i915_gem.h"
#include "i915_gem_gtt.h"
#include "i915_gpu_error.h"
@@ -284,6 +285,8 @@ struct drm_i915_file_private {
/** ban_score: Accumulated score of all ctx bans and fast hangs. */
atomic_t ban_score;
unsigned long hang_timestamp;
+
+ struct i915_drm_client *client;
};

/* Interface history:
@@ -1196,6 +1199,8 @@ struct drm_i915_private {

struct i915_pmu pmu;

+ struct i915_drm_clients clients;
+
struct i915_hdcp_comp_master *hdcp_master;
bool hdcp_comp_added;

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 981e383d1a5d..3df78babe1a9 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1177,25 +1177,40 @@ void i915_gem_cleanup_early(struct drm_i915_private *dev_priv)
int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file)
{
struct drm_i915_file_private *file_priv;
- int ret;
+ struct i915_drm_client *client;
+ int ret = -ENOMEM;

DRM_DEBUG("\n");

file_priv = kzalloc(sizeof(*file_priv), GFP_KERNEL);
if (!file_priv)
- return -ENOMEM;
+ goto err_alloc;
+
+ client = i915_drm_client_add(&i915->clients);
+ if (IS_ERR(client)) {
+ ret = PTR_ERR(client);
+ goto err_client;
+ }

file->driver_priv = file_priv;
file_priv->dev_priv = i915;
file_priv->file = file;
+ file_priv->client = client;

file_priv->bsd_engine = -1;
file_priv->hang_timestamp = jiffies;

ret = i915_gem_context_open(i915, file);
if (ret)
- kfree(file_priv);
+ goto err_context;
+
+ return 0;

+err_context:
+ i915_drm_client_put(client);
+err_client:
+ kfree(file_priv);
+err_alloc:
return ret;
}

--
2.30.2