bool unpinned;
/*
- * Attempt to pin all of the buffers into the GTT.
- * This is done in 2 phases:
+ * We have one more buffers that we couldn't bind, which could be due to
+ * various reasons. To resolve this we have 4 passes, with every next
+ * level turning the screws tighter:
*
- * 1. Unbind all objects that do not match the GTT constraints for
- * the execbuffer (fenceable, mappable, alignment etc).
- * 2. Bind new objects.
+ * 0. Unbind all objects that do not match the GTT constraints for the
+ * execbuffer (fenceable, mappable, alignment etc). Bind all new
+ * objects. This avoids unnecessary unbinding of later objects in order
+ * to make room for the earlier objects *unless* we need to defragment.
*
- * This avoid unnecessary unbinding of later objects in order to make
- * room for the earlier objects *unless* we need to defragment.
+ * 1. Reorder the buffers, where objects with the most restrictive
+ * placement requirements go first (ignoring fixed location buffers for
+ * now). For example, objects needing the mappable aperture (the first
+ * 256M of GTT), should go first vs objects that can be placed just
+ * about anywhere. Repeat the previous pass.
*
- * Defragmenting is skipped if all objects are pinned at a fixed location.
+ * 2. Consider buffers that are pinned at a fixed location. Also try to
+ * evict the entire VM this time, leaving only objects that we were
+ * unable to lock. Try again to bind the buffers. (still using the new
+ * buffer order).
+ *
+ * 3. We likely have object lock contention for one or more stubborn
+ * objects in the VM, for which we need to evict to make forward
+ * progress (perhaps we are fighting the shrinker?). When evicting the
+ * VM this time around, anything that we can't lock we now track using
+ * the busy_bo, using the full lock (after dropping the vm->mutex to
+ * prevent deadlocks), instead of trylock. We then continue to evict the
+ * VM, this time with the stubborn object locked, which we can now
+ * hopefully unbind (if still bound in the VM). Repeat until the VM is
+ * evicted. Finally we should be able bind everything.
*/
- for (pass = 0; pass <= 2; pass++) {
+ for (pass = 0; pass <= 3; pass++) {
int pin_flags = PIN_USER | PIN_VALIDATE;
if (pass == 0)
pin_flags |= PIN_NONBLOCK;
if (pass >= 1)
- unpinned = eb_unbind(eb, pass == 2);
+ unpinned = eb_unbind(eb, pass >= 2);
if (pass == 2) {
err = mutex_lock_interruptible(&eb->context->vm->mutex);
if (!err) {
- err = i915_gem_evict_vm(eb->context->vm, &eb->ww);
+ err = i915_gem_evict_vm(eb->context->vm, &eb->ww, NULL);
+ mutex_unlock(&eb->context->vm->mutex);
+ }
+ if (err)
+ return err;
+ }
+
+ if (pass == 3) {
+retry:
+ err = mutex_lock_interruptible(&eb->context->vm->mutex);
+ if (!err) {
+ struct drm_i915_gem_object *busy_bo = NULL;
+
+ err = i915_gem_evict_vm(eb->context->vm, &eb->ww, &busy_bo);
mutex_unlock(&eb->context->vm->mutex);
+ if (err && busy_bo) {
+ err = i915_gem_object_lock(busy_bo, &eb->ww);
+ i915_gem_object_put(busy_bo);
+ if (!err)
+ goto retry;
+ }
}
if (err)
return err;
if (vma == ERR_PTR(-ENOSPC)) {
ret = mutex_lock_interruptible(&ggtt->vm.mutex);
if (!ret) {
- ret = i915_gem_evict_vm(&ggtt->vm, &ww);
+ ret = i915_gem_evict_vm(&ggtt->vm, &ww, NULL);
mutex_unlock(&ggtt->vm.mutex);
}
if (ret)
if (vma == ERR_PTR(-ENOSPC)) {
ret = mutex_lock_interruptible(&ggtt->vm.mutex);
if (!ret) {
- ret = i915_gem_evict_vm(&ggtt->vm, &ww);
+ ret = i915_gem_evict_vm(&ggtt->vm, &ww, NULL);
mutex_unlock(&ggtt->vm.mutex);
}
if (ret)
* @vm: Address space to cleanse
* @ww: An optional struct i915_gem_ww_ctx. If not NULL, i915_gem_evict_vm
* will be able to evict vma's locked by the ww as well.
+ * @busy_bo: Optional pointer to struct drm_i915_gem_object. If not NULL, then
+ * in the event i915_gem_evict_vm() is unable to trylock an object for eviction,
+ * then @busy_bo will point to it. -EBUSY is also returned. The caller must drop
+ * the vm->mutex, before trying again to acquire the contended lock. The caller
+ * also owns a reference to the object.
*
* This function evicts all vmas from a vm.
*
* To clarify: This is for freeing up virtual address space, not for freeing
* memory in e.g. the shrinker.
*/
-int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww)
+int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww,
+ struct drm_i915_gem_object **busy_bo)
{
int ret = 0;
* the resv is shared among multiple objects, we still
* need the object ref.
*/
- if (dying_vma(vma) ||
+ if (!i915_gem_object_get_rcu(vma->obj) ||
(ww && (dma_resv_locking_ctx(vma->obj->base.resv) == &ww->ctx))) {
__i915_vma_pin(vma);
list_add(&vma->evict_link, &locked_eviction_list);
continue;
}
- if (!i915_gem_object_trylock(vma->obj, ww))
+ if (!i915_gem_object_trylock(vma->obj, ww)) {
+ if (busy_bo) {
+ *busy_bo = vma->obj; /* holds ref */
+ ret = -EBUSY;
+ break;
+ }
+ i915_gem_object_put(vma->obj);
continue;
+ }
__i915_vma_pin(vma);
list_add(&vma->evict_link, &eviction_list);
if (list_empty(&eviction_list) && list_empty(&locked_eviction_list))
break;
- ret = 0;
/* Unbind locked objects first, before unlocking the eviction_list */
list_for_each_entry_safe(vma, vn, &locked_eviction_list, evict_link) {
__i915_vma_unpin(vma);
- if (ret == 0)
+ if (ret == 0) {
ret = __i915_vma_unbind(vma);
- if (ret != -EINTR) /* "Get me out of here!" */
- ret = 0;
+ if (ret != -EINTR) /* "Get me out of here!" */
+ ret = 0;
+ }
+ if (!dying_vma(vma))
+ i915_gem_object_put(vma->obj);
}
list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) {
__i915_vma_unpin(vma);
- if (ret == 0)
+ if (ret == 0) {
ret = __i915_vma_unbind(vma);
- if (ret != -EINTR) /* "Get me out of here!" */
- ret = 0;
+ if (ret != -EINTR) /* "Get me out of here!" */
+ ret = 0;
+ }
i915_gem_object_unlock(vma->obj);
+ i915_gem_object_put(vma->obj);
}
} while (ret == 0);
struct drm_mm_node;
struct i915_address_space;
struct i915_gem_ww_ctx;
+struct drm_i915_gem_object;
int __must_check i915_gem_evict_something(struct i915_address_space *vm,
struct i915_gem_ww_ctx *ww,
struct drm_mm_node *node,
unsigned int flags);
int i915_gem_evict_vm(struct i915_address_space *vm,
- struct i915_gem_ww_ctx *ww);
+ struct i915_gem_ww_ctx *ww,
+ struct drm_i915_gem_object **busy_bo);
#endif /* __I915_GEM_EVICT_H__ */
* locked objects when called from execbuf when pinning
* is removed. This would probably regress badly.
*/
- i915_gem_evict_vm(vm, NULL);
+ i915_gem_evict_vm(vm, NULL, NULL);
mutex_unlock(&vm->mutex);
}
} while (1);
/* Everything is pinned, nothing should happen */
mutex_lock(&ggtt->vm.mutex);
- err = i915_gem_evict_vm(&ggtt->vm, NULL);
+ err = i915_gem_evict_vm(&ggtt->vm, NULL, NULL);
mutex_unlock(&ggtt->vm.mutex);
if (err) {
pr_err("i915_gem_evict_vm on a full GGTT returned err=%d]\n",
for_i915_gem_ww(&ww, err, false) {
mutex_lock(&ggtt->vm.mutex);
- err = i915_gem_evict_vm(&ggtt->vm, &ww);
+ err = i915_gem_evict_vm(&ggtt->vm, &ww, NULL);
mutex_unlock(&ggtt->vm.mutex);
}
projects / openbsd / commitdiff