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authorThomas Hellstrom <thellstrom@vmware.com>2013-10-09 03:18:07 -0700
committerThomas Hellstrom <thellstrom@vmware.com>2013-11-06 04:14:43 -0800
commitcbe12e74ee4e29b6cb4e63fa284e80b73ad57926 (patch)
treeef667b3eca6206be60d338af822ab707365d1f74
parent4695b03970df378dcb93fe3e7158381f1e980fa2 (diff)
drm/ttm: Allow vm fault retries
Make use of the FAULT_FLAG_ALLOW_RETRY flag to allow dropping the mmap_sem while waiting for bo idle. FAULT_FLAG_ALLOW_RETRY appears to be primarily designed for disk waits but should work just as fine for GPU waits.. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
-rw-r--r--drivers/gpu/drm/ttm/ttm_bo_vm.c62
1 files changed, 50 insertions, 12 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 1006c15445e9..c03514b93f9c 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -41,6 +41,51 @@
#define TTM_BO_VM_NUM_PREFAULT 16
+static int ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo,
+ struct vm_area_struct *vma,
+ struct vm_fault *vmf)
+{
+ struct ttm_bo_device *bdev = bo->bdev;
+ int ret = 0;
+
+ spin_lock(&bdev->fence_lock);
+ if (likely(!test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)))
+ goto out_unlock;
+
+ /*
+ * Quick non-stalling check for idle.
+ */
+ ret = ttm_bo_wait(bo, false, false, true);
+ if (likely(ret == 0))
+ goto out_unlock;
+
+ /*
+ * If possible, avoid waiting for GPU with mmap_sem
+ * held.
+ */
+ if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) {
+ ret = VM_FAULT_RETRY;
+ if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
+ goto out_unlock;
+
+ up_read(&vma->vm_mm->mmap_sem);
+ (void) ttm_bo_wait(bo, false, true, false);
+ goto out_unlock;
+ }
+
+ /*
+ * Ordinary wait.
+ */
+ ret = ttm_bo_wait(bo, false, true, false);
+ if (unlikely(ret != 0))
+ ret = (ret != -ERESTARTSYS) ? VM_FAULT_SIGBUS :
+ VM_FAULT_NOPAGE;
+
+out_unlock:
+ spin_unlock(&bdev->fence_lock);
+ return ret;
+}
+
static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
@@ -91,18 +136,11 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
* Wait for buffer data in transit, due to a pipelined
* move.
*/
-
- spin_lock(&bdev->fence_lock);
- if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
- ret = ttm_bo_wait(bo, false, true, false);
- spin_unlock(&bdev->fence_lock);
- if (unlikely(ret != 0)) {
- retval = (ret != -ERESTARTSYS) ?
- VM_FAULT_SIGBUS : VM_FAULT_NOPAGE;
- goto out_unlock;
- }
- } else
- spin_unlock(&bdev->fence_lock);
+ ret = ttm_bo_vm_fault_idle(bo, vma, vmf);
+ if (unlikely(ret != 0)) {
+ retval = ret;
+ goto out_unlock;
+ }
ret = ttm_mem_io_lock(man, true);
if (unlikely(ret != 0)) {