Require lru_lock and reservation to be held, kill off the loop, no
new sync objects should be attached at this point any more.
v2:
- moved upwards in patch list and fixed conflicts.
v3:
- rebase for fence lock, and rename to ttm_bo_cleanup_refs_and_unlock
for clarity that it unlocks lru.
v4:
- add WARN_ON(!atomic_read(&bo->kref.refcount)) in reserve to ensure
that nobody accidentally reserves a dead buffer.
Signed-off-by: Maarten Lankhorst <maarten.lankho...@canonical.com>
---
drivers/gpu/drm/ttm/ttm_bo.c | 123 ++++++++++++++++-----------------
drivers/gpu/drm/ttm/ttm_execbuf_util.c | 1 +
2 files changed, 62 insertions(+), 62 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 70285ff..e6df086 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -296,6 +296,8 @@ int ttm_bo_reserve(struct ttm_buffer_object *bo,
int put_count = 0;
int ret;
+ WARN_ON(!atomic_read(&bo->kref.refcount));
+
spin_lock(&glob->lru_lock);
ret = ttm_bo_reserve_locked(bo, interruptible, no_wait, use_sequence,
sequence);
@@ -522,82 +524,78 @@ queue:
}
/**
- * function ttm_bo_cleanup_refs
+ * function ttm_bo_cleanup_refs_and_unlock
* If bo idle, remove from delayed- and lru lists, and unref.
* If not idle, do nothing.
*
+ * Must be called with lru_lock and reservation held, this function
+ * will drop both before returning.
+ *
* @interruptible Any sleeps should occur interruptibly.
- * @no_wait_reserve Never wait for reserve. Return -EBUSY instead.
* @no_wait_gpu Never wait for gpu. Return -EBUSY instead.
*/
-static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
- bool interruptible,
- bool no_wait_reserve,
- bool no_wait_gpu)
+static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
+ bool interruptible,
+ bool no_wait_gpu)
{
struct ttm_bo_device *bdev = bo->bdev;
struct ttm_bo_driver *driver = bdev->driver;
struct ttm_bo_global *glob = bo->glob;
int put_count;
int ret = 0;
- void *sync_obj;
-
-retry:
- spin_lock(&glob->lru_lock);
-
- ret = ttm_bo_reserve_locked(bo, interruptible,
- no_wait_reserve, false, 0);
- if (unlikely(ret)) {
- spin_unlock(&glob->lru_lock);
- return ret;
- }
+ spin_lock(&bdev->fence_lock);
+ ret = ttm_bo_wait(bo, false, false, true);
- if (unlikely(list_empty(&bo->ddestroy))) {
+ if (ret && no_wait_gpu) {
+ spin_unlock(&bdev->fence_lock);
atomic_set(&bo->reserved, 0);
wake_up_all(&bo->event_queue);
spin_unlock(&glob->lru_lock);
- return 0;
- }
-
- spin_lock(&bdev->fence_lock);
- ret = ttm_bo_wait(bo, false, false, true);
- if (ret) {
- if (no_wait_gpu) {
- spin_unlock(&bdev->fence_lock);
- atomic_set(&bo->reserved, 0);
- wake_up_all(&bo->event_queue);
- spin_unlock(&glob->lru_lock);
- return ret;
- }
+ return ret;
+ } else if (ret) {
+ void *sync_obj;
/**
- * Take a reference to the fence and unreserve, if the wait
- * was succesful and no new sync_obj was attached,
- * ttm_bo_wait in retry will return ret = 0, and end the loop.
+ * Take a reference to the fence and unreserve,
+ * at this point the buffer should be dead, so
+ * no new sync objects can be attached.
*/
-
sync_obj = driver->sync_obj_ref(&bo->sync_obj);
spin_unlock(&bdev->fence_lock);
atomic_set(&bo->reserved, 0);
wake_up_all(&bo->event_queue);
spin_unlock(&glob->lru_lock);
- ret = driver->sync_obj_wait(bo->sync_obj, false, interruptible);
+ ret = driver->sync_obj_wait(sync_obj, false, interruptible);
driver->sync_obj_unref(&sync_obj);
if (ret)
return ret;
- goto retry;
+ spin_lock(&glob->lru_lock);
+
+ /* remove sync_obj with ttm_bo_wait */
+ spin_lock(&bdev->fence_lock);
+ ret = ttm_bo_wait(bo, false, false, true);
+ spin_unlock(&bdev->fence_lock);
+
+ WARN_ON(ret);
+
+ } else {
+ spin_unlock(&bdev->fence_lock);
+ atomic_set(&bo->reserved, 0);
+ wake_up_all(&bo->event_queue);
+ }
+
+ if (unlikely(list_empty(&bo->ddestroy))) {
+ spin_unlock(&glob->lru_lock);
+ return 0;
}
- spin_unlock(&bdev->fence_lock);
put_count = ttm_bo_del_from_lru(bo);
list_del_init(&bo->ddestroy);
++put_count;
- atomic_set(&bo->reserved, 0);
- wake_up_all(&bo->event_queue);
spin_unlock(&glob->lru_lock);
ttm_bo_list_ref_sub(bo, put_count, true);
@@ -606,8 +604,8 @@ retry:
}
/**
- * Traverse the delayed list, and call ttm_bo_cleanup_refs on all
- * encountered buffers.
+ * Traverse the delayed list, and call ttm_bo_cleanup_refs_and_unlock
+ * on all encountered buffers.
*/
static int ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all)
@@ -633,9 +631,14 @@ static int ttm_bo_delayed_delete(struct ttm_bo_device
*bdev, bool remove_all)
kref_get(&nentry->list_kref);
}
- spin_unlock(&glob->lru_lock);
- ret = ttm_bo_cleanup_refs(entry, false, !remove_all,
- !remove_all);
+ ret = ttm_bo_reserve_locked(entry, false, !remove_all,
+ false, 0);
+ if (ret)
+ spin_unlock(&glob->lru_lock);
+ else
+ ret = ttm_bo_cleanup_refs_and_unlock(entry, false,
+ !remove_all);
+
kref_put(&entry->list_kref, ttm_bo_release_list);
entry = nentry;
@@ -788,15 +791,6 @@ retry:
bo = list_first_entry(&man->lru, struct ttm_buffer_object, lru);
kref_get(&bo->list_kref);
- if (!list_empty(&bo->ddestroy)) {
- spin_unlock(&glob->lru_lock);
- ret = ttm_bo_cleanup_refs(bo, interruptible,
- no_wait_reserve, no_wait_gpu);
- kref_put(&bo->list_kref, ttm_bo_release_list);
-
- return ret;
- }
-
ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
if (unlikely(ret == -EBUSY)) {
@@ -815,6 +809,13 @@ retry:
goto retry;
}
+ if (!list_empty(&bo->ddestroy)) {
+ ret = ttm_bo_cleanup_refs_and_unlock(bo, interruptible,
+ no_wait_gpu);
+ kref_put(&bo->list_kref, ttm_bo_release_list);
+ return ret;
+ }
+
put_count = ttm_bo_del_from_lru(bo);
spin_unlock(&glob->lru_lock);
@@ -1778,14 +1779,6 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
struct ttm_buffer_object, swap);
kref_get(&bo->list_kref);
- if (!list_empty(&bo->ddestroy)) {
- spin_unlock(&glob->lru_lock);
- (void) ttm_bo_cleanup_refs(bo, false, false, false);
- kref_put(&bo->list_kref, ttm_bo_release_list);
- spin_lock(&glob->lru_lock);
- continue;
- }
-
/**
* Reserve buffer. Since we unlock while sleeping, we need
* to re-check that nobody removed us from the swap-list while
@@ -1801,6 +1794,12 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
}
}
+ if (!list_empty(&bo->ddestroy)) {
+ ret = ttm_bo_cleanup_refs_and_unlock(bo, false, false);
+ kref_put(&bo->list_kref, ttm_bo_release_list);
+ return ret;
+ }
+
BUG_ON(ret != 0);
put_count = ttm_bo_del_from_lru(bo);
spin_unlock(&glob->lru_lock);
diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index cd9e452..5490492 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -152,6 +152,7 @@ retry:
list_for_each_entry(entry, list, head) {
struct ttm_buffer_object *bo = entry->bo;
+ WARN_ON(!atomic_read(&bo->kref.refcount));
retry_this_bo:
ret = ttm_bo_reserve_locked(bo, true, true, true, val_seq);
switch (ret) {
--
1.8.0
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