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drm/i915: Objects on the unbound list may still have an active reference
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Due to the lazy retirement semantics, even though we have unbound an
object, it may still hold onto an active reference. So in the debug code,
play safe.

v2: Export i915_gem_shrink() rather than opencoding it.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Chris Wilson authored and Daniel Vetter committed Sep 19, 2014
1 parent 344c5bb commit 21ab4e7
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Showing 3 changed files with 74 additions and 77 deletions.
34 changes: 4 additions & 30 deletions drivers/gpu/drm/i915/i915_debugfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3826,7 +3826,6 @@ i915_drop_caches_set(void *data, u64 val)
{
struct drm_device *dev = data;
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_gem_object *obj, *next;
int ret;

DRM_DEBUG("Dropping caches: 0x%08llx\n", val);
Expand All @@ -3846,36 +3845,11 @@ i915_drop_caches_set(void *data, u64 val)
if (val & (DROP_RETIRE | DROP_ACTIVE))
i915_gem_retire_requests(dev);

if (val & DROP_BOUND) {
list_for_each_entry_safe(obj, next, &dev_priv->mm.bound_list,
global_list) {
struct i915_vma *vma, *v;
if (val & DROP_BOUND)
i915_gem_shrink(dev_priv, LONG_MAX, I915_SHRINK_BOUND);

ret = 0;
drm_gem_object_reference(&obj->base);
list_for_each_entry_safe(vma, v, &obj->vma_list, vma_link) {
if (vma->pin_count)
continue;

ret = i915_vma_unbind(vma);
if (ret)
break;
}
drm_gem_object_unreference(&obj->base);
if (ret)
goto unlock;
}
}

if (val & DROP_UNBOUND) {
list_for_each_entry_safe(obj, next, &dev_priv->mm.unbound_list,
global_list)
if (obj->pages_pin_count == 0) {
ret = i915_gem_object_put_pages(obj);
if (ret)
goto unlock;
}
}
if (val & DROP_UNBOUND)
i915_gem_shrink(dev_priv, LONG_MAX, I915_SHRINK_UNBOUND);

unlock:
mutex_unlock(&dev->struct_mutex);
Expand Down
6 changes: 6 additions & 0 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2368,6 +2368,12 @@ int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
int i915_gem_wait_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv);
void i915_gem_load(struct drm_device *dev);
unsigned long i915_gem_shrink(struct drm_i915_private *dev_priv,
long target,
unsigned flags);
#define I915_SHRINK_PURGEABLE 0x1
#define I915_SHRINK_UNBOUND 0x2
#define I915_SHRINK_BOUND 0x4
void *i915_gem_object_alloc(struct drm_device *dev);
void i915_gem_object_free(struct drm_i915_gem_object *obj);
void i915_gem_object_init(struct drm_i915_gem_object *obj,
Expand Down
111 changes: 64 additions & 47 deletions drivers/gpu/drm/i915/i915_gem.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,6 @@ static unsigned long i915_gem_shrinker_scan(struct shrinker *shrinker,
static int i915_gem_shrinker_oom(struct notifier_block *nb,
unsigned long event,
void *ptr);
static unsigned long i915_gem_purge(struct drm_i915_private *dev_priv, long target);
static unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv);

static bool cpu_cache_is_coherent(struct drm_device *dev,
Expand Down Expand Up @@ -1741,7 +1740,11 @@ static int i915_gem_object_create_mmap_offset(struct drm_i915_gem_object *obj)
* offsets on purgeable objects by truncating it and marking it purged,
* which prevents userspace from ever using that object again.
*/
i915_gem_purge(dev_priv, obj->base.size >> PAGE_SHIFT);
i915_gem_shrink(dev_priv,
obj->base.size >> PAGE_SHIFT,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_PURGEABLE);
ret = drm_gem_create_mmap_offset(&obj->base);
if (ret != -ENOSPC)
goto out;
Expand Down Expand Up @@ -1938,12 +1941,11 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
return 0;
}

static unsigned long
__i915_gem_shrink(struct drm_i915_private *dev_priv, long target,
bool purgeable_only)
unsigned long
i915_gem_shrink(struct drm_i915_private *dev_priv,
long target, unsigned flags)
{
struct list_head still_in_list;
struct drm_i915_gem_object *obj;
const bool purgeable_only = flags & I915_SHRINK_PURGEABLE;
unsigned long count = 0;

/*
Expand All @@ -1965,62 +1967,68 @@ __i915_gem_shrink(struct drm_i915_private *dev_priv, long target,
* dev->struct_mutex and so we won't ever be able to observe an
* object on the bound_list with a reference count equals 0.
*/
INIT_LIST_HEAD(&still_in_list);
while (count < target && !list_empty(&dev_priv->mm.unbound_list)) {
obj = list_first_entry(&dev_priv->mm.unbound_list,
typeof(*obj), global_list);
list_move_tail(&obj->global_list, &still_in_list);
if (flags & I915_SHRINK_UNBOUND) {
struct list_head still_in_list;

if (!i915_gem_object_is_purgeable(obj) && purgeable_only)
continue;
INIT_LIST_HEAD(&still_in_list);
while (count < target && !list_empty(&dev_priv->mm.unbound_list)) {
struct drm_i915_gem_object *obj;

drm_gem_object_reference(&obj->base);
obj = list_first_entry(&dev_priv->mm.unbound_list,
typeof(*obj), global_list);
list_move_tail(&obj->global_list, &still_in_list);

if (i915_gem_object_put_pages(obj) == 0)
count += obj->base.size >> PAGE_SHIFT;
if (!i915_gem_object_is_purgeable(obj) && purgeable_only)
continue;

drm_gem_object_unreference(&obj->base);
drm_gem_object_reference(&obj->base);

if (i915_gem_object_put_pages(obj) == 0)
count += obj->base.size >> PAGE_SHIFT;

drm_gem_object_unreference(&obj->base);
}
list_splice(&still_in_list, &dev_priv->mm.unbound_list);
}
list_splice(&still_in_list, &dev_priv->mm.unbound_list);

INIT_LIST_HEAD(&still_in_list);
while (count < target && !list_empty(&dev_priv->mm.bound_list)) {
struct i915_vma *vma, *v;
if (flags & I915_SHRINK_BOUND) {
struct list_head still_in_list;

obj = list_first_entry(&dev_priv->mm.bound_list,
typeof(*obj), global_list);
list_move_tail(&obj->global_list, &still_in_list);
INIT_LIST_HEAD(&still_in_list);
while (count < target && !list_empty(&dev_priv->mm.bound_list)) {
struct drm_i915_gem_object *obj;
struct i915_vma *vma, *v;

if (!i915_gem_object_is_purgeable(obj) && purgeable_only)
continue;
obj = list_first_entry(&dev_priv->mm.bound_list,
typeof(*obj), global_list);
list_move_tail(&obj->global_list, &still_in_list);

drm_gem_object_reference(&obj->base);
if (!i915_gem_object_is_purgeable(obj) && purgeable_only)
continue;

list_for_each_entry_safe(vma, v, &obj->vma_list, vma_link)
if (i915_vma_unbind(vma))
break;
drm_gem_object_reference(&obj->base);

if (i915_gem_object_put_pages(obj) == 0)
count += obj->base.size >> PAGE_SHIFT;
list_for_each_entry_safe(vma, v, &obj->vma_list, vma_link)
if (i915_vma_unbind(vma))
break;

drm_gem_object_unreference(&obj->base);
if (i915_gem_object_put_pages(obj) == 0)
count += obj->base.size >> PAGE_SHIFT;

drm_gem_object_unreference(&obj->base);
}
list_splice(&still_in_list, &dev_priv->mm.bound_list);
}
list_splice(&still_in_list, &dev_priv->mm.bound_list);

return count;
}

static unsigned long
i915_gem_purge(struct drm_i915_private *dev_priv, long target)
{
return __i915_gem_shrink(dev_priv, target, true);
}

static unsigned long
i915_gem_shrink_all(struct drm_i915_private *dev_priv)
{
i915_gem_evict_everything(dev_priv->dev);
return __i915_gem_shrink(dev_priv, LONG_MAX, false);
return i915_gem_shrink(dev_priv, LONG_MAX,
I915_SHRINK_BOUND | I915_SHRINK_UNBOUND);
}

static int
Expand Down Expand Up @@ -2067,7 +2075,11 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
for (i = 0; i < page_count; i++) {
page = shmem_read_mapping_page_gfp(mapping, i, gfp);
if (IS_ERR(page)) {
i915_gem_purge(dev_priv, page_count);
i915_gem_shrink(dev_priv,
page_count,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_PURGEABLE);
page = shmem_read_mapping_page_gfp(mapping, i, gfp);
}
if (IS_ERR(page)) {
Expand Down Expand Up @@ -5261,11 +5273,16 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
if (!i915_gem_shrinker_lock(dev, &unlock))
return SHRINK_STOP;

freed = i915_gem_purge(dev_priv, sc->nr_to_scan);
freed = i915_gem_shrink(dev_priv,
sc->nr_to_scan,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_PURGEABLE);
if (freed < sc->nr_to_scan)
freed += __i915_gem_shrink(dev_priv,
sc->nr_to_scan - freed,
false);
freed += i915_gem_shrink(dev_priv,
sc->nr_to_scan - freed,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND);
if (unlock)
mutex_unlock(&dev->struct_mutex);

Expand Down

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