Commit 31169714 authored by Chris Wilson's avatar Chris Wilson Committed by Jesse Barnes
Browse files

drm/i915: Register a shrinker to free inactive lists under memory pressure 



This should help GEM handle memory pressure sitatuions more gracefully.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 725ceaa0

drivers/gpu/drm/i915/i915_drv.c

+3 −0
Original line number Diff line number Diff line
@@ -362,6 +362,8 @@ static int __init i915_init(void) 
{

	driver.num_ioctls = i915_max_ioctl;



	i915_gem_shrinker_init();



	/*

	 * If CONFIG_DRM_I915_KMS is set, default to KMS unless

	 * explicitly disabled with the module pararmeter.
@@ -388,6 +390,7 @@ static int __init i915_init(void) 


static void __exit i915_exit(void)

{

	i915_gem_shrinker_exit();

	drm_exit(&driver);

}

drivers/gpu/drm/i915/i915_drv.h

+12 −0
Original line number Diff line number Diff line
@@ -368,6 +368,15 @@ typedef struct drm_i915_private { 
		struct io_mapping *gtt_mapping;

		int gtt_mtrr;



		/**

		 * Membership on list of all loaded devices, used to evict

		 * inactive buffers under memory pressure.

		 *

		 * Modifications should only be done whilst holding the

		 * shrink_list_lock spinlock.

		 */

		struct list_head shrink_list;



		/**

		 * List of objects currently involved in rendering from the

		 * ringbuffer.
@@ -741,6 +750,9 @@ int i915_gem_object_get_pages(struct drm_gem_object *obj); 
void i915_gem_object_put_pages(struct drm_gem_object *obj);

void i915_gem_release(struct drm_device * dev, struct drm_file *file_priv);



void i915_gem_shrinker_init(void);

void i915_gem_shrinker_exit(void);



/* i915_gem_tiling.c */

void i915_gem_detect_bit_6_swizzle(struct drm_device *dev);

void i915_gem_object_do_bit_17_swizzle(struct drm_gem_object *obj);

drivers/gpu/drm/i915/i915_gem.c

+144 −0
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ static int i915_gem_phys_pwrite(struct drm_device *dev, struct drm_gem_object *o 
				struct drm_i915_gem_pwrite *args,

				struct drm_file *file_priv);



static LIST_HEAD(shrink_list);

static DEFINE_SPINLOCK(shrink_list_lock);



int i915_gem_do_init(struct drm_device *dev, unsigned long start,

		     unsigned long end)

{
@@ -4265,6 +4268,10 @@ i915_gem_load(struct drm_device *dev) 
			  i915_gem_retire_work_handler);

	dev_priv->mm.next_gem_seqno = 1;



	spin_lock(&shrink_list_lock);

	list_add(&dev_priv->mm.shrink_list, &shrink_list);

	spin_unlock(&shrink_list_lock);



	/* Old X drivers will take 0-2 for front, back, depth buffers */

	dev_priv->fence_reg_start = 3;
@@ -4482,3 +4489,140 @@ void i915_gem_release(struct drm_device * dev, struct drm_file *file_priv) 
		list_del_init(i915_file_priv->mm.request_list.next);

	mutex_unlock(&dev->struct_mutex);

}



/* Immediately discard the backing storage */

static void

i915_gem_object_truncate(struct drm_gem_object *obj)

{

    struct inode *inode;



    inode = obj->filp->f_path.dentry->d_inode;



    mutex_lock(&inode->i_mutex);

    truncate_inode_pages(inode->i_mapping, 0);

    mutex_unlock(&inode->i_mutex);

}



static inline int

i915_gem_object_is_purgeable(struct drm_i915_gem_object *obj_priv)

{

	return !obj_priv->dirty;

}



static int

i915_gem_shrink(int nr_to_scan, gfp_t gfp_mask)

{

	drm_i915_private_t *dev_priv, *next_dev;

	struct drm_i915_gem_object *obj_priv, *next_obj;

	int cnt = 0;

	int would_deadlock = 1;



	/* "fast-path" to count number of available objects */

	if (nr_to_scan == 0) {

		spin_lock(&shrink_list_lock);

		list_for_each_entry(dev_priv, &shrink_list, mm.shrink_list) {

			struct drm_device *dev = dev_priv->dev;



			if (mutex_trylock(&dev->struct_mutex)) {

				list_for_each_entry(obj_priv,

						    &dev_priv->mm.inactive_list,

						    list)

					cnt++;

				mutex_unlock(&dev->struct_mutex);

			}

		}

		spin_unlock(&shrink_list_lock);



		return (cnt / 100) * sysctl_vfs_cache_pressure;

	}



	spin_lock(&shrink_list_lock);



	/* first scan for clean buffers */

	list_for_each_entry_safe(dev_priv, next_dev,

				 &shrink_list, mm.shrink_list) {

		struct drm_device *dev = dev_priv->dev;



		if (! mutex_trylock(&dev->struct_mutex))

			continue;



		spin_unlock(&shrink_list_lock);



		i915_gem_retire_requests(dev);



		list_for_each_entry_safe(obj_priv, next_obj,

					 &dev_priv->mm.inactive_list,

					 list) {

			if (i915_gem_object_is_purgeable(obj_priv)) {

				struct drm_gem_object *obj = obj_priv->obj;

				i915_gem_object_unbind(obj);

				i915_gem_object_truncate(obj);



				if (--nr_to_scan <= 0)

					break;

			}

		}



		spin_lock(&shrink_list_lock);

		mutex_unlock(&dev->struct_mutex);



		if (nr_to_scan <= 0)

			break;

	}



	/* second pass, evict/count anything still on the inactive list */

	list_for_each_entry_safe(dev_priv, next_dev,

				 &shrink_list, mm.shrink_list) {

		struct drm_device *dev = dev_priv->dev;



		if (! mutex_trylock(&dev->struct_mutex))

			continue;



		spin_unlock(&shrink_list_lock);



		list_for_each_entry_safe(obj_priv, next_obj,

					 &dev_priv->mm.inactive_list,

					 list) {

			if (nr_to_scan > 0) {

				struct drm_gem_object *obj = obj_priv->obj;

				i915_gem_object_unbind(obj);

				if (i915_gem_object_is_purgeable(obj_priv))

					i915_gem_object_truncate(obj);



				nr_to_scan--;

			} else

				cnt++;

		}



		spin_lock(&shrink_list_lock);

		mutex_unlock(&dev->struct_mutex);



		would_deadlock = 0;

	}



	spin_unlock(&shrink_list_lock);



	if (would_deadlock)

		return -1;

	else if (cnt > 0)

		return (cnt / 100) * sysctl_vfs_cache_pressure;

	else

		return 0;

}



static struct shrinker shrinker = {

	.shrink = i915_gem_shrink,

	.seeks = DEFAULT_SEEKS,

};



__init void

i915_gem_shrinker_init(void)

{

    register_shrinker(&shrinker);

}



__exit void

i915_gem_shrinker_exit(void)

{

    unregister_shrinker(&shrinker);

}