Re: [Intel-gfx] [RFC PATCH 8/9] drm/gem: Associate GEM objects with drm cgroup

[Thomas Zimmermann <tzimmermann@suse.de>]

[-- Attachment #1.1.1: Type: text/plain, Size: 6771 bytes --]

Hi

Am 09.02.21 um 11:54 schrieb Daniel Vetter:
> *: vmwgfx is the only non-gem driver, but there's plans to move at least
> vmwgfx internals (maybe not the uapi, we'll see) over to gem. Once that's
> done it's truly all gpu memory.

Do you have a URL to the discussion?

While I recent worked on GEM, I thought that vmwgfx could easily switch 
to the GEM internals without adopting the interface.

Personally, I think we should consider renaming struct drm_gem_object et 
al. It's not strictly GEM UAPI, but nowadays anything memory-related. 
Maybe drm_mem_object would fit.

Best regards
Thomas

>> ---
>>   drivers/gpu/drm/drm_gem.c | 89 +++++++++++++++++++++++++++++++++++++++
>>   include/drm/drm_gem.h     | 17 ++++++++
>>   2 files changed, 106 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>> index c2ce78c4edc3..a12da41eaafe 100644
>> --- a/drivers/gpu/drm/drm_gem.c
>> +++ b/drivers/gpu/drm/drm_gem.c
>> @@ -29,6 +29,7 @@
>>   #include <linux/slab.h>
>>   #include <linux/mm.h>
>>   #include <linux/uaccess.h>
>> +#include <linux/cgroup_drm.h>
>>   #include <linux/fs.h>
>>   #include <linux/file.h>
>>   #include <linux/module.h>
>> @@ -112,6 +113,89 @@ drm_gem_init(struct drm_device *dev)
>>   	return drmm_add_action(dev, drm_gem_init_release, NULL);
>>   }
>>   
>> +/**
>> + * drm_gem_object_set_cgroup - associate GEM object with a cgroup
>> + * @obj: GEM object which is being associated with a cgroup
>> + * @task: task associated with process control group to use
>> + *
>> + * This will acquire a reference on cgroup and use for charging GEM
>> + * memory allocations.
>> + * This helper could be extended in future to migrate charges to another
>> + * cgroup, print warning if this usage occurs.
>> + */
>> +void drm_gem_object_set_cgroup(struct drm_gem_object *obj,
>> +			       struct task_struct *task)
>> +{
>> +	/* if object has existing cgroup, we migrate the charge... */
>> +	if (obj->drmcg) {
>> +		pr_warn("DRM: need to migrate cgroup charge of %lld\n",
>> +			atomic64_read(&obj->drmcg_bytes_charged));
>> +	}
>> +	obj->drmcg = drmcg_get(task);
>> +}
>> +EXPORT_SYMBOL(drm_gem_object_set_cgroup);
>> +
>> +/**
>> + * drm_gem_object_unset_cgroup - clear GEM object's associated cgroup
>> + * @obj: GEM object
>> + *
>> + * This will release a reference on cgroup.
>> + */
>> +void drm_gem_object_unset_cgroup(struct drm_gem_object *obj)
>> +{
>> +	WARN_ON(atomic64_read(&obj->drmcg_bytes_charged));
>> +	drmcg_put(obj->drmcg);
>> +}
>> +EXPORT_SYMBOL(drm_gem_object_unset_cgroup);
>> +
>> +/**
>> + * drm_gem_object_charge_mem - try charging size bytes to DRM cgroup
>> + * @obj: GEM object which is being charged
>> + * @size: number of bytes to charge
>> + *
>> + * Try to charge @size bytes to GEM object's associated DRM cgroup.  This
>> + * will fail if a successful charge would cause the current device memory
>> + * usage to go above the cgroup's GPU memory maximum limit.
>> + *
>> + * Returns 0 on success.  Otherwise, an error code is returned.
>> + */
>> +int drm_gem_object_charge_mem(struct drm_gem_object *obj, u64 size)
>> +{
>> +	int ret;
>> +
>> +	ret = drm_cgroup_try_charge(obj->drmcg, obj->dev,
>> +				    DRMCG_TYPE_MEM_CURRENT, size);
>> +	if (!ret)
>> +		atomic64_add(size, &obj->drmcg_bytes_charged);
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_gem_object_charge_mem);
>> +
>> +/**
>> + * drm_gem_object_uncharge_mem - uncharge size bytes from DRM cgroup
>> + * @obj: GEM object which is being uncharged
>> + * @size: number of bytes to uncharge
>> + *
>> + * Uncharge @size bytes from the DRM cgroup associated with specified
>> + * GEM object.
>> + *
>> + * Returns 0 on success.  Otherwise, an error code is returned.
>> + */
>> +void drm_gem_object_uncharge_mem(struct drm_gem_object *obj, u64 size)
>> +{
>> +	u64 charged = atomic64_read(&obj->drmcg_bytes_charged);
>> +
>> +	if (WARN_ON(!charged))
>> +		return;
>> +	if (WARN_ON(size > charged))
>> +		size = charged;
>> +
>> +	atomic64_sub(size, &obj->drmcg_bytes_charged);
>> +	drm_cgroup_uncharge(obj->drmcg, obj->dev, DRMCG_TYPE_MEM_CURRENT,
>> +			    size);
>> +}
>> +EXPORT_SYMBOL(drm_gem_object_uncharge_mem);
>> +
>>   /**
>>    * drm_gem_object_init - initialize an allocated shmem-backed GEM object
>>    * @dev: drm_device the object should be initialized for
>> @@ -156,6 +240,8 @@ void drm_gem_private_object_init(struct drm_device *dev,
>>   	obj->dev = dev;
>>   	obj->filp = NULL;
>>   
>> +	drm_gem_object_set_cgroup(obj, current);
>> +
>>   	kref_init(&obj->refcount);
>>   	obj->handle_count = 0;
>>   	obj->size = size;
>> @@ -950,6 +1036,9 @@ drm_gem_object_release(struct drm_gem_object *obj)
>>   
>>   	dma_resv_fini(&obj->_resv);
>>   	drm_gem_free_mmap_offset(obj);
>> +
>> +	/* Release reference on cgroup used with GEM object charging */
>> +	drm_gem_object_unset_cgroup(obj);
>>   }
>>   EXPORT_SYMBOL(drm_gem_object_release);
>>   
>> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
>> index 240049566592..06ea10fc17bc 100644
>> --- a/include/drm/drm_gem.h
>> +++ b/include/drm/drm_gem.h
>> @@ -37,6 +37,7 @@
>>   #include <linux/kref.h>
>>   #include <linux/dma-resv.h>
>>   
>> +#include <drm/drm_cgroup.h>
>>   #include <drm/drm_vma_manager.h>
>>   
>>   struct dma_buf_map;
>> @@ -222,6 +223,17 @@ struct drm_gem_object {
>>   	 */
>>   	struct file *filp;
>>   
>> +	/**
>> +	 * @drmcg:
>> +	 *
>> +	 * cgroup used for charging GEM object page allocations against. This
>> +	 * is set to the current cgroup during GEM object creation.
>> +	 * Charging policy is up to the DRM driver to implement and should be
>> +	 * charged when allocating backing store from device memory.
>> +	 */
>> +	struct drmcg *drmcg;
>> +	atomic64_t drmcg_bytes_charged;
>> +
>>   	/**
>>   	 * @vma_node:
>>   	 *
>> @@ -417,4 +429,9 @@ int drm_gem_fence_array_add_implicit(struct xarray *fence_array,
>>   int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
>>   			    u32 handle, u64 *offset);
>>   
>> +void drm_gem_object_set_cgroup(struct drm_gem_object *obj,
>> +			       struct task_struct *task);
>> +void drm_gem_object_unset_cgroup(struct drm_gem_object *obj);
>> +int drm_gem_object_charge_mem(struct drm_gem_object *obj, u64 size);
>> +void drm_gem_object_uncharge_mem(struct drm_gem_object *obj, u64 size);
>>   #endif /* __DRM_GEM_H__ */
>> -- 
>> 2.20.1
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


[-- Attachment #1.2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx