int ttm_bo_reserve_locked(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_cmpxchg(&bo->reserved, 0, 1) != 0)) {
if (use_sequence && bo->seq_valid &&
(sequence - bo->val_seq < (1 << 31))) {
return -EAGAIN;
}
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;
}
if (use_sequence) {
bo->val_seq = sequence;
bo->seq_valid = true;
} else {
bo->seq_valid = false;
}
return 0;
}
int ttm_bo_reserve_locked(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_cmpxchg(&bo->reserved, 0, 1) != 0)) {
/**
* Deadlock avoidance for multi-bo reserving.
*/
if (use_sequence && bo->seq_valid) {
/**
* We've already reserved this one.
*/
if (unlikely(sequence == bo->val_seq))
return -EDEADLK;
/**
* Already reserved by a thread that will not back
* off for us. We need to back off.
*/
if (unlikely(sequence - bo->val_seq < (1 << 31)))
return -EAGAIN;
}
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;
}
if (use_sequence) {
/**
* 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);
bo->val_seq = sequence;
bo->seq_valid = true;
} else {
bo->seq_valid = false;
}
return 0;
}
static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
uint32_t mem_type,
bool interruptible, bool no_wait_reserve,
bool no_wait_gpu)
{
struct ttm_bo_global *glob = bdev->glob;
struct ttm_mem_type_manager *man = &bdev->man[mem_type];
struct ttm_buffer_object *bo;
int ret, put_count = 0;
retry:
spin_lock(&glob->lru_lock);
if (list_empty(&man->lru)) {
spin_unlock(&glob->lru_lock);
return -EBUSY;
}
bo = list_first_entry(&man->lru, struct ttm_buffer_object, lru);
kref_get(&bo->list_kref);
ret = ttm_bo_reserve_locked(bo, false, no_wait_reserve, false, 0);
if (unlikely(ret == -EBUSY)) {
spin_unlock(&glob->lru_lock);
if (likely(!no_wait_gpu))
ret = ttm_bo_wait_unreserved(bo, interruptible);
kref_put(&bo->list_kref, ttm_bo_release_list);
/**
* We *need* to retry after releasing the lru lock.
*/
if (unlikely(ret != 0))
return ret;
goto retry;
}
put_count = ttm_bo_del_from_lru(bo);
spin_unlock(&glob->lru_lock);
BUG_ON(ret != 0);
while (put_count--)
kref_put(&bo->list_kref, ttm_bo_ref_bug);
ret = ttm_bo_evict(bo, interruptible, no_wait_reserve, no_wait_gpu);
ttm_bo_unreserve(bo);
kref_put(&bo->list_kref, ttm_bo_release_list);
return ret;
}
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;
}
static int ttm_bo_swapout(struct ttm_mem_shrink *shrink)
{
struct ttm_bo_global *glob =
container_of(shrink, struct ttm_bo_global, shrink);
struct ttm_buffer_object *bo;
int ret = -EBUSY;
int put_count;
uint32_t swap_placement = (TTM_PL_FLAG_CACHED | TTM_PL_FLAG_SYSTEM);
spin_lock(&glob->lru_lock);
while (ret == -EBUSY) {
if (unlikely(list_empty(&glob->swap_lru))) {
spin_unlock(&glob->lru_lock);
return -EBUSY;
}
bo = list_first_entry(&glob->swap_lru,
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);
continue;
}
/**
* Reserve buffer. Since we unlock while sleeping, we need
* to re-check that nobody removed us from the swap-list while
* we slept.
*/
ret = ttm_bo_reserve_locked(bo, false, true, false, 0);
if (unlikely(ret == -EBUSY)) {
spin_unlock(&glob->lru_lock);
ttm_bo_wait_unreserved(bo, false);
kref_put(&bo->list_kref, ttm_bo_release_list);
spin_lock(&glob->lru_lock);
}
}
BUG_ON(ret != 0);
put_count = ttm_bo_del_from_lru(bo);
spin_unlock(&glob->lru_lock);
ttm_bo_list_ref_sub(bo, put_count, true);
/**
* Wait for GPU, then move to system cached.
*/
spin_lock(&bo->bdev->fence_lock);
ret = ttm_bo_wait(bo, false, false, false);
spin_unlock(&bo->bdev->fence_lock);
if (unlikely(ret != 0))
goto out;
if ((bo->mem.placement & swap_placement) != swap_placement) {
struct ttm_mem_reg evict_mem;
evict_mem = bo->mem;
evict_mem.mm_node = NULL;
evict_mem.placement = TTM_PL_FLAG_SYSTEM | TTM_PL_FLAG_CACHED;
evict_mem.mem_type = TTM_PL_SYSTEM;
ret = ttm_bo_handle_move_mem(bo, &evict_mem, true,
false, false, false);
if (unlikely(ret != 0))
goto out;
}
ttm_bo_unmap_virtual(bo);
/**
* Swap out. Buffer will be swapped in again as soon as
* anyone tries to access a ttm page.
*/
if (bo->bdev->driver->swap_notify)
bo->bdev->driver->swap_notify(bo);
ret = ttm_tt_swapout(bo->ttm, bo->persistent_swap_storage);
out:
/**
*
* Unreserve without putting on LRU to avoid swapping out an
* already swapped buffer.
*/
atomic_set(&bo->reserved, 0);
wake_up_all(&bo->event_queue);
kref_put(&bo->list_kref, ttm_bo_release_list);
return ret;
}
