[Intel-gfx] [PATCH] drm/i915: Expose engine properties via sysfs

Tvrtko Ursulin tvrtko.ursulin at linux.intel.com
Wed Sep 18 10:26:57 UTC 2019


On 18/09/2019 10:23, Chris Wilson wrote:
> Preliminary stub to add engines underneath /sys/class/drm/cardN/, so
> that we can expose properties on each engine to the sysadmin.

Do we also envisage a need for these future things we'll expose to be 
per-context-engine and not just per physical engine?

> 
> To start with we have basic analogues of the i915_query ioctl so that we
> can pretty print engine discovery from the shell, and flesh out the
> directory structure. Later we will add writeable sysadmin properties such
> as per-engine timeout controls.

It would be good to show an example of the layout in commit text.

> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
>   drivers/gpu/drm/i915/Makefile                |   3 +-
>   drivers/gpu/drm/i915/gt/intel_engine_sysfs.c | 113 +++++++++++++++++++
>   drivers/gpu/drm/i915/gt/intel_engine_sysfs.h |  14 +++
>   drivers/gpu/drm/i915/i915_sysfs.c            |   4 +
>   4 files changed, 133 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
>   create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> 
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 658b930d34a8..bbea0d4dadd6 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -76,8 +76,9 @@ gt-y += \
>   	gt/intel_breadcrumbs.o \
>   	gt/intel_context.o \
>   	gt/intel_engine_cs.o \
> -	gt/intel_engine_pool.o \
>   	gt/intel_engine_pm.o \
> +	gt/intel_engine_pool.o \
> +	gt/intel_engine_sysfs.o \
>   	gt/intel_engine_user.o \
>   	gt/intel_gt.o \
>   	gt/intel_gt_irq.o \
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
> new file mode 100644
> index 000000000000..51b4b3f2a808
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
> @@ -0,0 +1,113 @@
> +/*
> + * SPDX-License-Identifier: MIT
> + *
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#include <linux/kobject.h>
> +#include <linux/sysfs.h>
> +
> +#include "i915_drv.h"
> +#include "intel_engine.h"
> +#include "intel_engine_sysfs.h"
> +
> +struct kobj_engine {
> +	struct kobject base;
> +	struct intel_engine_cs *engine;
> +};
> +
> +static struct intel_engine_cs *kobj_to_engine(struct kobject *kobj)
> +{
> +	return container_of(kobj, struct kobj_engine, base)->engine;
> +}
> +
> +static ssize_t
> +name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%s\n", kobj_to_engine(kobj)->name);

Name contains our internal instance number which I think we don't want 
to export.

On the other hand we could think of dmesg as user visible so could 
consider tweaking engine->name to be built from uabi components.

> +}
> +
> +static ssize_t
> +class_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_class);
> +}
> +
> +static ssize_t
> +inst_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_instance);
> +}
> +
> +static ssize_t
> +mmio_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "0x%x\n", kobj_to_engine(kobj)->mmio_base);
> +}

Nice try ;) but I suggest you leave adding mmio for a separate patch.

> +
> +static struct kobj_attribute name_attr = __ATTR(name, 0444, name_show, NULL);
> +static struct kobj_attribute class_attr = __ATTR(class, 0444, class_show, NULL);
> +static struct kobj_attribute inst_attr = __ATTR(instance, 0444, inst_show, NULL);
> +static struct kobj_attribute mmio_attr = __ATTR(instance, 0444, mmio_show, NULL);
> +
> +static void kobj_engine_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}
> +
> +static struct kobj_type kobj_engine_type = {
> +	.release = kobj_engine_release,
> +	.sysfs_ops = &kobj_sysfs_ops
> +};
> +
> +static struct kobject *
> +kobj_engine(struct kobject *dir, struct intel_engine_cs *engine)
> +{
> +	struct kobj_engine *ke;
> +
> +	ke = kzalloc(sizeof(*ke), GFP_KERNEL);
> +	if (!ke)
> +		return NULL;

Could embed kobj into the engine?

> +
> +	kobject_init(&ke->base, &kobj_engine_type);
> +	ke->engine = engine;
> +
> +	if (kobject_add(&ke->base, dir, "%s", engine->name)) {
> +		kobject_put(&ke->base);
> +		return NULL;
> +	}
> +
> +	return &ke->base;
> +}
> +
> +void intel_engines_add_sysfs(struct drm_i915_private *i915)
> +{
> +	static const struct attribute *files[] = {
> +		&name_attr.attr,
> +		&class_attr.attr,
> +		&inst_attr.attr,
> +		&mmio_attr.attr,
> +	};
> +
> +	struct device *kdev = i915->drm.primary->kdev;
> +	struct intel_engine_cs *engine;
> +	struct kobject *dir;
> +
> +	dir = kobject_create_and_add("engine", &kdev->kobj);
> +	if (!dir)
> +		return;
> +
> +	for_each_uabi_engine(engine, i915) {
> +		struct kobject *kobj;
> +
> +		kobj = kobj_engine(dir, engine);
> +		if (!kobj)
> +			continue;

Could be consistent and log an error in this case as well.

> +
> +		if (sysfs_create_files(kobj, files)) {
> +			dev_err(kdev, "Failed to add sysfs engine '%s'\n",
> +				engine->name);
> +			break;

Leaks kobj.

> +		}
> +	}
> +}
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> new file mode 100644
> index 000000000000..ef44a745b70a
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> @@ -0,0 +1,14 @@
> +/*
> + * SPDX-License-Identifier: MIT
> + *
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#ifndef INTEL_ENGINE_SYSFS_H
> +#define INTEL_ENGINE_SYSFS_H
> +
> +struct drm_i915_private;
> +
> +void intel_engines_add_sysfs(struct drm_i915_private *i915);
> +
> +#endif /* INTEL_ENGINE_SYSFS_H */
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> index d8a3b180c084..6b88d934927a 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -30,6 +30,8 @@
>   #include <linux/stat.h>
>   #include <linux/sysfs.h>
>   
> +#include "gt/intel_engine_sysfs.h"
> +
>   #include "i915_drv.h"
>   #include "i915_sysfs.h"
>   #include "intel_pm.h"
> @@ -618,6 +620,8 @@ void i915_setup_sysfs(struct drm_i915_private *dev_priv)
>   		DRM_ERROR("RPS sysfs setup failed\n");
>   
>   	i915_setup_error_capture(kdev);
> +
> +	intel_engines_add_sysfs(dev_priv);

Or gt?

>   }
>   
>   void i915_teardown_sysfs(struct drm_i915_private *dev_priv)
> 

Regards,

Tvrtko


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