diff options
Diffstat (limited to 'drivers/gpu/drm/ttm')
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo.c | 103 | ||||
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_execbuf_util.c | 78 |
2 files changed, 126 insertions, 55 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 52b20b12c83a..9b07b7d44a58 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -158,7 +158,8 @@ static void ttm_bo_release_list(struct kref *list_kref) ttm_mem_global_free(bdev->glob->mem_glob, acc_size); } -int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) +static int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, + bool interruptible) { if (interruptible) { return wait_event_interruptible(bo->event_queue, @@ -168,7 +169,6 @@ int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) return 0; } } -EXPORT_SYMBOL(ttm_bo_wait_unreserved); void ttm_bo_add_to_lru(struct ttm_buffer_object *bo) { @@ -213,14 +213,13 @@ int ttm_bo_del_from_lru(struct ttm_buffer_object *bo) return put_count; } -int ttm_bo_reserve_locked(struct ttm_buffer_object *bo, +int ttm_bo_reserve_nolru(struct ttm_buffer_object *bo, bool interruptible, bool no_wait, bool use_sequence, uint32_t sequence) { - struct ttm_bo_global *glob = bo->glob; int ret; - while (unlikely(atomic_read(&bo->reserved) != 0)) { + while (unlikely(atomic_xchg(&bo->reserved, 1) != 0)) { /** * Deadlock avoidance for multi-bo reserving. */ @@ -241,26 +240,36 @@ int ttm_bo_reserve_locked(struct ttm_buffer_object *bo, if (no_wait) return -EBUSY; - spin_unlock(&glob->lru_lock); ret = ttm_bo_wait_unreserved(bo, interruptible); - spin_lock(&glob->lru_lock); if (unlikely(ret)) return ret; } - atomic_set(&bo->reserved, 1); if (use_sequence) { + bool wake_up = false; /** * Wake up waiters that may need to recheck for deadlock, * if we decreased the sequence number. */ if (unlikely((bo->val_seq - sequence < (1 << 31)) || !bo->seq_valid)) - wake_up_all(&bo->event_queue); + wake_up = true; + /* + * In the worst case with memory ordering these values can be + * seen in the wrong order. However since we call wake_up_all + * in that case, this will hopefully not pose a problem, + * and the worst case would only cause someone to accidentally + * hit -EAGAIN in ttm_bo_reserve when they see old value of + * val_seq. However this would only happen if seq_valid was + * written before val_seq was, and just means some slightly + * increased cpu usage + */ bo->val_seq = sequence; bo->seq_valid = true; + if (wake_up) + wake_up_all(&bo->event_queue); } else { bo->seq_valid = false; } @@ -289,17 +298,64 @@ int ttm_bo_reserve(struct ttm_buffer_object *bo, int put_count = 0; int ret; - spin_lock(&glob->lru_lock); - ret = ttm_bo_reserve_locked(bo, interruptible, no_wait, use_sequence, - sequence); - if (likely(ret == 0)) + ret = ttm_bo_reserve_nolru(bo, interruptible, no_wait, use_sequence, + sequence); + if (likely(ret == 0)) { + spin_lock(&glob->lru_lock); put_count = ttm_bo_del_from_lru(bo); - spin_unlock(&glob->lru_lock); + spin_unlock(&glob->lru_lock); + ttm_bo_list_ref_sub(bo, put_count, true); + } - ttm_bo_list_ref_sub(bo, put_count, true); + return ret; +} + +int ttm_bo_reserve_slowpath_nolru(struct ttm_buffer_object *bo, + bool interruptible, uint32_t sequence) +{ + bool wake_up = false; + int ret; + + while (unlikely(atomic_xchg(&bo->reserved, 1) != 0)) { + WARN_ON(bo->seq_valid && sequence == bo->val_seq); + + ret = ttm_bo_wait_unreserved(bo, interruptible); + if (unlikely(ret)) + return ret; + } + + if ((bo->val_seq - sequence < (1 << 31)) || !bo->seq_valid) + wake_up = true; + + /** + * Wake up waiters that may need to recheck for deadlock, + * if we decreased the sequence number. + */ + bo->val_seq = sequence; + bo->seq_valid = true; + if (wake_up) + wake_up_all(&bo->event_queue); + + return 0; +} + +int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo, + bool interruptible, uint32_t sequence) +{ + struct ttm_bo_global *glob = bo->glob; + int put_count, ret; + + ret = ttm_bo_reserve_slowpath_nolru(bo, interruptible, sequence); + if (likely(!ret)) { + spin_lock(&glob->lru_lock); + put_count = ttm_bo_del_from_lru(bo); + spin_unlock(&glob->lru_lock); + ttm_bo_list_ref_sub(bo, put_count, true); + } return ret; } +EXPORT_SYMBOL(ttm_bo_reserve_slowpath); void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo) { @@ -511,7 +567,7 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) int ret; spin_lock(&glob->lru_lock); - ret = ttm_bo_reserve_locked(bo, false, true, false, 0); + ret = ttm_bo_reserve_nolru(bo, false, true, false, 0); spin_lock(&bdev->fence_lock); (void) ttm_bo_wait(bo, false, false, true); @@ -604,7 +660,7 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo, return ret; spin_lock(&glob->lru_lock); - ret = ttm_bo_reserve_locked(bo, false, true, false, 0); + ret = ttm_bo_reserve_nolru(bo, false, true, false, 0); /* * We raced, and lost, someone else holds the reservation now, @@ -668,7 +724,14 @@ static int ttm_bo_delayed_delete(struct ttm_bo_device *bdev, bool remove_all) kref_get(&nentry->list_kref); } - ret = ttm_bo_reserve_locked(entry, false, !remove_all, false, 0); + ret = ttm_bo_reserve_nolru(entry, false, true, false, 0); + if (remove_all && ret) { + spin_unlock(&glob->lru_lock); + ret = ttm_bo_reserve_nolru(entry, false, false, + false, 0); + spin_lock(&glob->lru_lock); + } + if (!ret) ret = ttm_bo_cleanup_refs_and_unlock(entry, false, !remove_all); @@ -816,7 +879,7 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev, spin_lock(&glob->lru_lock); list_for_each_entry(bo, &man->lru, lru) { - ret = ttm_bo_reserve_locked(bo, false, true, false, 0); + ret = ttm_bo_reserve_nolru(bo, false, true, false, 0); if (!ret) break; } @@ -1797,7 +1860,7 @@ static int ttm_bo_swapout(struct ttm_mem_shrink *shrink) spin_lock(&glob->lru_lock); list_for_each_entry(bo, &glob->swap_lru, swap) { - ret = ttm_bo_reserve_locked(bo, false, true, false, 0); + ret = ttm_bo_reserve_nolru(bo, false, true, false, 0); if (!ret) break; } diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c index cd9e4523dc56..7b90def15674 100644 --- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c +++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c @@ -82,22 +82,6 @@ static void ttm_eu_list_ref_sub(struct list_head *list) } } -static int ttm_eu_wait_unreserved_locked(struct list_head *list, - struct ttm_buffer_object *bo) -{ - struct ttm_bo_global *glob = bo->glob; - int ret; - - ttm_eu_del_from_lru_locked(list); - spin_unlock(&glob->lru_lock); - ret = ttm_bo_wait_unreserved(bo, true); - spin_lock(&glob->lru_lock); - if (unlikely(ret != 0)) - ttm_eu_backoff_reservation_locked(list); - return ret; -} - - void ttm_eu_backoff_reservation(struct list_head *list) { struct ttm_validate_buffer *entry; @@ -145,47 +129,65 @@ int ttm_eu_reserve_buffers(struct list_head *list) entry = list_first_entry(list, struct ttm_validate_buffer, head); glob = entry->bo->glob; -retry: spin_lock(&glob->lru_lock); val_seq = entry->bo->bdev->val_seq++; +retry: list_for_each_entry(entry, list, head) { struct ttm_buffer_object *bo = entry->bo; -retry_this_bo: - ret = ttm_bo_reserve_locked(bo, true, true, true, val_seq); + /* already slowpath reserved? */ + if (entry->reserved) + continue; + + ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq); switch (ret) { case 0: break; case -EBUSY: - ret = ttm_eu_wait_unreserved_locked(list, bo); - if (unlikely(ret != 0)) { - spin_unlock(&glob->lru_lock); - ttm_eu_list_ref_sub(list); - return ret; - } - goto retry_this_bo; + ttm_eu_del_from_lru_locked(list); + spin_unlock(&glob->lru_lock); + ret = ttm_bo_reserve_nolru(bo, true, false, + true, val_seq); + spin_lock(&glob->lru_lock); + if (!ret) + break; + + if (unlikely(ret != -EAGAIN)) + goto err; + + /* fallthrough */ case -EAGAIN: ttm_eu_backoff_reservation_locked(list); + + /* + * temporarily increase sequence number every retry, + * to prevent us from seeing our old reservation + * sequence when someone else reserved the buffer, + * but hasn't updated the seq_valid/seqno members yet. + */ + val_seq = entry->bo->bdev->val_seq++; + spin_unlock(&glob->lru_lock); ttm_eu_list_ref_sub(list); - ret = ttm_bo_wait_unreserved(bo, true); + ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq); if (unlikely(ret != 0)) return ret; + spin_lock(&glob->lru_lock); + entry->reserved = true; + if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { + ret = -EBUSY; + goto err; + } goto retry; default: - ttm_eu_backoff_reservation_locked(list); - spin_unlock(&glob->lru_lock); - ttm_eu_list_ref_sub(list); - return ret; + goto err; } entry->reserved = true; if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { - ttm_eu_backoff_reservation_locked(list); - spin_unlock(&glob->lru_lock); - ttm_eu_list_ref_sub(list); - return -EBUSY; + ret = -EBUSY; + goto err; } } @@ -194,6 +196,12 @@ retry_this_bo: ttm_eu_list_ref_sub(list); return 0; + +err: + ttm_eu_backoff_reservation_locked(list); + spin_unlock(&glob->lru_lock); + ttm_eu_list_ref_sub(list); + return ret; } EXPORT_SYMBOL(ttm_eu_reserve_buffers); |