drm/i915: Move object backing storage manipulation to its own locking
Break the allocation of the backing storage away from struct_mutex into a per-object lock. This allows parallel page allocation, provided we can do so outside of struct_mutex (i.e. set-domain-ioctl, pwrite, GTT fault), i.e. before execbuf! The increased cost of the atomic counters are hidden behind i915_vma_pin() for the typical case of execbuf, i.e. as the object is typically bound between execbufs, the page_pin_count is static. The cost will be felt around set-domain and pwrite, but offset by the improvement from reduced struct_mutex contention. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-14-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson
Родитель
03ac84f183
Коммит
1233e2db19
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@ -2274,7 +2274,8 @@ struct drm_i915_gem_object {
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unsigned int pin_display;
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struct {
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unsigned int pages_pin_count;
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struct mutex lock; /* protects the pages and their use */
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atomic_t pages_pin_count;
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struct sg_table *pages;
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void *mapping;
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@ -2387,13 +2388,6 @@ i915_gem_object_is_dead(const struct drm_i915_gem_object *obj)
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return atomic_read(&obj->base.refcount.refcount) == 0;
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}
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#if IS_ENABLED(CONFIG_LOCKDEP)
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#define lockdep_assert_held_unless(lock, cond) \
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GEM_BUG_ON(debug_locks && !lockdep_is_held(lock) && !(cond))
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#else
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#define lockdep_assert_held_unless(lock, cond)
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#endif
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static inline bool
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i915_gem_object_has_struct_page(const struct drm_i915_gem_object *obj)
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{
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@ -3229,9 +3223,9 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
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static inline int __must_check
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i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
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{
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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might_lock(&obj->mm.lock);
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if (obj->mm.pages_pin_count++)
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if (atomic_inc_not_zero(&obj->mm.pages_pin_count))
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return 0;
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return __i915_gem_object_get_pages(obj);
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@ -3240,32 +3234,29 @@ i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
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static inline void
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__i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
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{
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lockdep_assert_held_unless(&obj->base.dev->struct_mutex,
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i915_gem_object_is_dead(obj));
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GEM_BUG_ON(!obj->mm.pages);
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obj->mm.pages_pin_count++;
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atomic_inc(&obj->mm.pages_pin_count);
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}
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static inline bool
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i915_gem_object_has_pinned_pages(struct drm_i915_gem_object *obj)
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{
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return obj->mm.pages_pin_count;
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return atomic_read(&obj->mm.pages_pin_count);
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}
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static inline void
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__i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
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{
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lockdep_assert_held_unless(&obj->base.dev->struct_mutex,
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i915_gem_object_is_dead(obj));
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GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
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GEM_BUG_ON(!obj->mm.pages);
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obj->mm.pages_pin_count--;
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GEM_BUG_ON(obj->mm.pages_pin_count < obj->bind_count);
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atomic_dec(&obj->mm.pages_pin_count);
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GEM_BUG_ON(atomic_read(&obj->mm.pages_pin_count) < obj->bind_count);
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}
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static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
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static inline void
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i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
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{
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__i915_gem_object_unpin_pages(obj);
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}
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@ -3288,8 +3279,8 @@ enum i915_map_type {
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* the kernel address space. Based on the @type of mapping, the PTE will be
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* set to either WriteBack or WriteCombine (via pgprot_t).
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*
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* The caller must hold the struct_mutex, and is responsible for calling
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* i915_gem_object_unpin_map() when the mapping is no longer required.
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* The caller is responsible for calling i915_gem_object_unpin_map() when the
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* mapping is no longer required.
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*
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* Returns the pointer through which to access the mapped object, or an
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* ERR_PTR() on error.
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@ -3305,12 +3296,9 @@ void *__must_check i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
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* with your access, call i915_gem_object_unpin_map() to release the pin
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* upon the mapping. Once the pin count reaches zero, that mapping may be
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* removed.
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*
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* The caller must hold the struct_mutex.
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*/
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static inline void i915_gem_object_unpin_map(struct drm_i915_gem_object *obj)
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{
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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i915_gem_object_unpin_pages(obj);
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}
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@ -2269,6 +2269,9 @@ void __i915_gem_object_invalidate(struct drm_i915_gem_object *obj)
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{
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struct address_space *mapping;
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lockdep_assert_held(&obj->mm.lock);
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GEM_BUG_ON(obj->mm.pages);
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switch (obj->mm.madv) {
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case I915_MADV_DONTNEED:
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i915_gem_object_truncate(obj);
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@ -2325,12 +2328,17 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
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{
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struct sg_table *pages;
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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if (i915_gem_object_has_pinned_pages(obj))
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return;
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GEM_BUG_ON(obj->bind_count);
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if (!READ_ONCE(obj->mm.pages))
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return;
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/* May be called by shrinker from within get_pages() (on another bo) */
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mutex_lock_nested(&obj->mm.lock, SINGLE_DEPTH_NESTING);
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if (unlikely(atomic_read(&obj->mm.pages_pin_count)))
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goto unlock;
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/* ->put_pages might need to allocate memory for the bit17 swizzle
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* array, hence protect them from being reaped by removing them from gtt
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@ -2353,6 +2361,8 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
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__i915_gem_object_reset_page_iter(obj);
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obj->ops->put_pages(obj, pages);
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unlock:
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mutex_unlock(&obj->mm.lock);
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}
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static unsigned int swiotlb_max_size(void)
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@ -2486,7 +2496,7 @@ err_pages:
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void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
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struct sg_table *pages)
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{
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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lockdep_assert_held(&obj->mm.lock);
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obj->mm.get_page.sg_pos = pages->sgl;
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obj->mm.get_page.sg_idx = 0;
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@ -2512,9 +2522,9 @@ static int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
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}
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/* Ensure that the associated pages are gathered from the backing storage
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* and pinned into our object. i915_gem_object_get_pages() may be called
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* and pinned into our object. i915_gem_object_pin_pages() may be called
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* multiple times before they are released by a single call to
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* i915_gem_object_put_pages() - once the pages are no longer referenced
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* i915_gem_object_unpin_pages() - once the pages are no longer referenced
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* either as a result of memory pressure (reaping pages under the shrinker)
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* or as the object is itself released.
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*/
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@ -2522,15 +2532,23 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
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{
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int err;
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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err = mutex_lock_interruptible(&obj->mm.lock);
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if (err)
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return err;
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if (obj->mm.pages)
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return 0;
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if (likely(obj->mm.pages)) {
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__i915_gem_object_pin_pages(obj);
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goto unlock;
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}
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GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
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err = ____i915_gem_object_get_pages(obj);
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if (err)
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__i915_gem_object_unpin_pages(obj);
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if (!err)
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atomic_set_release(&obj->mm.pages_pin_count, 1);
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unlock:
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mutex_unlock(&obj->mm.lock);
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return err;
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}
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@ -2590,20 +2608,29 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
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void *ptr;
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int ret;
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lockdep_assert_held(&obj->base.dev->struct_mutex);
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GEM_BUG_ON(!i915_gem_object_has_struct_page(obj));
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ret = i915_gem_object_pin_pages(obj);
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ret = mutex_lock_interruptible(&obj->mm.lock);
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if (ret)
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return ERR_PTR(ret);
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pinned = obj->mm.pages_pin_count > 1;
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pinned = true;
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if (!atomic_inc_not_zero(&obj->mm.pages_pin_count)) {
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ret = ____i915_gem_object_get_pages(obj);
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if (ret)
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goto err_unlock;
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GEM_BUG_ON(atomic_read(&obj->mm.pages_pin_count));
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atomic_set_release(&obj->mm.pages_pin_count, 1);
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pinned = false;
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}
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GEM_BUG_ON(!obj->mm.pages);
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ptr = ptr_unpack_bits(obj->mm.mapping, has_type);
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if (ptr && has_type != type) {
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if (pinned) {
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ret = -EBUSY;
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goto err;
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goto err_unpin;
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}
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if (is_vmalloc_addr(ptr))
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@ -2618,17 +2645,21 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
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ptr = i915_gem_object_map(obj, type);
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if (!ptr) {
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ret = -ENOMEM;
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goto err;
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goto err_unpin;
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}
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obj->mm.mapping = ptr_pack_bits(ptr, type);
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}
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out_unlock:
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mutex_unlock(&obj->mm.lock);
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return ptr;
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err:
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i915_gem_object_unpin_pages(obj);
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return ERR_PTR(ret);
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err_unpin:
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atomic_dec(&obj->mm.pages_pin_count);
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err_unlock:
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ptr = ERR_PTR(ret);
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goto out_unlock;
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}
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static void
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@ -4268,7 +4299,7 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
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struct drm_i915_private *dev_priv = to_i915(dev);
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struct drm_i915_gem_madvise *args = data;
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struct drm_i915_gem_object *obj;
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int ret;
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int err;
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switch (args->madv) {
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case I915_MADV_DONTNEED:
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@ -4278,15 +4309,13 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
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return -EINVAL;
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}
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ret = i915_mutex_lock_interruptible(dev);
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if (ret)
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return ret;
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obj = i915_gem_object_lookup(file_priv, args->handle);
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if (!obj) {
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ret = -ENOENT;
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goto unlock;
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}
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if (!obj)
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return -ENOENT;
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err = mutex_lock_interruptible(&obj->mm.lock);
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if (err)
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goto out;
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if (obj->mm.pages &&
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i915_gem_object_is_tiled(obj) &&
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@ -4305,11 +4334,11 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
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i915_gem_object_truncate(obj);
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args->retained = obj->mm.madv != __I915_MADV_PURGED;
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mutex_unlock(&obj->mm.lock);
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out:
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i915_gem_object_put(obj);
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unlock:
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mutex_unlock(&dev->struct_mutex);
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return ret;
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return err;
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}
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void i915_gem_object_init(struct drm_i915_gem_object *obj,
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@ -4317,6 +4346,8 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
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{
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int i;
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mutex_init(&obj->mm.lock);
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INIT_LIST_HEAD(&obj->global_list);
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INIT_LIST_HEAD(&obj->userfault_link);
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for (i = 0; i < I915_NUM_ENGINES; i++)
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@ -4479,7 +4510,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
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obj->ops->release(obj);
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if (WARN_ON(i915_gem_object_has_pinned_pages(obj)))
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obj->mm.pages_pin_count = 0;
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atomic_set(&obj->mm.pages_pin_count, 0);
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if (discard_backing_storage(obj))
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obj->mm.madv = I915_MADV_DONTNEED;
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__i915_gem_object_put_pages(obj);
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@ -48,6 +48,20 @@ static bool mutex_is_locked_by(struct mutex *mutex, struct task_struct *task)
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#endif
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}
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static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
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{
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if (!mutex_trylock(&dev->struct_mutex)) {
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if (!mutex_is_locked_by(&dev->struct_mutex, current))
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return false;
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*unlock = false;
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} else {
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*unlock = true;
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}
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return true;
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}
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static bool any_vma_pinned(struct drm_i915_gem_object *obj)
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{
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struct i915_vma *vma;
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@ -66,6 +80,9 @@ static bool swap_available(void)
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static bool can_release_pages(struct drm_i915_gem_object *obj)
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{
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if (!obj->mm.pages)
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return false;
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/* Only shmemfs objects are backed by swap */
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if (!obj->base.filp)
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return false;
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@ -78,7 +95,7 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
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* to the GPU, simply unbinding from the GPU is not going to succeed
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* in releasing our pin count on the pages themselves.
|
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*/
|
||||
if (obj->mm.pages_pin_count > obj->bind_count)
|
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if (atomic_read(&obj->mm.pages_pin_count) > obj->bind_count)
|
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return false;
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|
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if (any_vma_pinned(obj))
|
||||
|
|
@ -95,7 +112,7 @@ static bool unsafe_drop_pages(struct drm_i915_gem_object *obj)
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{
|
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if (i915_gem_object_unbind(obj) == 0)
|
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__i915_gem_object_put_pages(obj);
|
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return !obj->mm.pages;
|
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return !READ_ONCE(obj->mm.pages);
|
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}
|
||||
|
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/**
|
||||
|
|
@ -135,6 +152,10 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
|
|||
{ NULL, 0 },
|
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}, *phase;
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unsigned long count = 0;
|
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bool unlock;
|
||||
|
||||
if (!i915_gem_shrinker_lock(&dev_priv->drm, &unlock))
|
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return 0;
|
||||
|
||||
trace_i915_gem_shrink(dev_priv, target, flags);
|
||||
i915_gem_retire_requests(dev_priv);
|
||||
|
|
@ -199,8 +220,14 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
|
|||
|
||||
i915_gem_object_get(obj);
|
||||
|
||||
if (unsafe_drop_pages(obj))
|
||||
if (unsafe_drop_pages(obj)) {
|
||||
mutex_lock(&obj->mm.lock);
|
||||
if (!obj->mm.pages) {
|
||||
__i915_gem_object_invalidate(obj);
|
||||
count += obj->base.size >> PAGE_SHIFT;
|
||||
}
|
||||
mutex_unlock(&obj->mm.lock);
|
||||
}
|
||||
|
||||
i915_gem_object_put(obj);
|
||||
}
|
||||
|
|
@ -211,6 +238,9 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
|
|||
intel_runtime_pm_put(dev_priv);
|
||||
|
||||
i915_gem_retire_requests(dev_priv);
|
||||
if (unlock)
|
||||
mutex_unlock(&dev_priv->drm.struct_mutex);
|
||||
|
||||
/* expedite the RCU grace period to free some request slabs */
|
||||
synchronize_rcu_expedited();
|
||||
|
||||
|
|
@ -244,19 +274,6 @@ unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
|
|||
return freed;
|
||||
}
|
||||
|
||||
static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock)
|
||||
{
|
||||
if (!mutex_trylock(&dev->struct_mutex)) {
|
||||
if (!mutex_is_locked_by(&dev->struct_mutex, current))
|
||||
return false;
|
||||
|
||||
*unlock = false;
|
||||
} else
|
||||
*unlock = true;
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
static unsigned long
|
||||
i915_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
|
||||
{
|
||||
|
|
|
|||
|
|
@ -259,6 +259,7 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
|
|||
if (!err) {
|
||||
struct i915_vma *vma;
|
||||
|
||||
mutex_lock(&obj->mm.lock);
|
||||
if (obj->mm.pages &&
|
||||
obj->mm.madv == I915_MADV_WILLNEED &&
|
||||
dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
|
||||
|
|
@ -267,6 +268,7 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
|
|||
if (!i915_gem_object_is_tiled(obj))
|
||||
__i915_gem_object_pin_pages(obj);
|
||||
}
|
||||
mutex_unlock(&obj->mm.lock);
|
||||
|
||||
list_for_each_entry(vma, &obj->vma_list, obj_link) {
|
||||
if (!vma->fence)
|
||||
|
|
|
|||
|
|
@ -79,7 +79,7 @@ static void cancel_userptr(struct work_struct *work)
|
|||
WARN_ONCE(obj->mm.pages,
|
||||
"Failed to release pages: bind_count=%d, pages_pin_count=%d, pin_display=%d\n",
|
||||
obj->bind_count,
|
||||
obj->mm.pages_pin_count,
|
||||
atomic_read(&obj->mm.pages_pin_count),
|
||||
obj->pin_display);
|
||||
|
||||
i915_gem_object_put(obj);
|
||||
|
|
@ -491,7 +491,6 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
|
|||
{
|
||||
struct get_pages_work *work = container_of(_work, typeof(*work), work);
|
||||
struct drm_i915_gem_object *obj = work->obj;
|
||||
struct drm_device *dev = obj->base.dev;
|
||||
const int npages = obj->base.size >> PAGE_SHIFT;
|
||||
struct page **pvec;
|
||||
int pinned, ret;
|
||||
|
|
@ -527,7 +526,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
|
|||
}
|
||||
}
|
||||
|
||||
mutex_lock(&dev->struct_mutex);
|
||||
mutex_lock(&obj->mm.lock);
|
||||
if (obj->userptr.work == &work->work) {
|
||||
struct sg_table *pages = ERR_PTR(ret);
|
||||
|
||||
|
|
@ -542,13 +541,12 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
|
|||
|
||||
obj->userptr.work = ERR_CAST(pages);
|
||||
}
|
||||
|
||||
i915_gem_object_put(obj);
|
||||
mutex_unlock(&dev->struct_mutex);
|
||||
mutex_unlock(&obj->mm.lock);
|
||||
|
||||
release_pages(pvec, pinned, 0);
|
||||
drm_free_large(pvec);
|
||||
|
||||
i915_gem_object_put_unlocked(obj);
|
||||
put_task_struct(work->task);
|
||||
kfree(work);
|
||||
}
|
||||
|
|
|
|||
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Ссылка в новой задаче