On 11/30/2012 09:05 AM, Maarten Lankhorst wrote:
Just use the return error from ttm_mem_evict_first instead.
Changes since v1:
- Add warning if list is not empty, nothing else we can do here.
Marten, when this function is called, all cross-device reservers have
been shut out with the TTM lock or whatever similar
mechanism is in place. It's a critical function that must succeed,
unless there is a hardware failure to evict.
As mentioned in the comments on the previous patch, ttm_bo_evict_first()
may return 0 (OK) if it failed to reclaim the
trylock in cleanup_refs_and_unlock(), with the assumption that another
process will destroy the bo anyway
(possibly at a later time which we know nothing about). The lru list
needs to be empty when this function returns.
This means we must either keep the while(list_empty) or perhaps better,
retry instead of WARN if list_empty() is detected at the end of list.
/Thomas
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 8ab23ae..9028327 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1323,25 +1323,25 @@ static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
struct ttm_bo_global *glob = bdev->glob;
int ret;
- /*
- * Can't use standard list traversal since we're unlocking.
- */
-
- spin_lock(&glob->lru_lock);
- while (!list_empty(&man->lru)) {
- spin_unlock(&glob->lru_lock);
+ do {
ret = ttm_mem_evict_first(bdev, mem_type, false, false);
- if (ret) {
- if (allow_errors) {
- return ret;
- } else {
- pr_err("Cleanup eviction failed\n");
- }
+ if (ret && ret != -EBUSY && !allow_errors) {
+ pr_err("Cleanup eviction failed with %i\n", ret);
+ ret = 0;
}
+ } while (!ret);
+
+ if (likely(ret == -EBUSY)) {
+ /*
+ * lru list should be empty, verify this is the case.
+ */
spin_lock(&glob->lru_lock);
+ WARN_ON(!list_empty(&man->lru));
+ if (list_empty(&man->lru) || !allow_errors)
+ ret = 0;
+ spin_unlock(&glob->lru_lock);
}
- spin_unlock(&glob->lru_lock);
- return 0;
+ return ret;
}
int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type)
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