On Tue, Nov 11, 2014 at 04:20:37PM +0900, Michel Dänzer wrote:
> From: Michel Dänzer <[email protected]>
>
> The radeon driver uses placement range restrictions for several reasons,
> in particular to make sure BOs in VRAM can be accessed by the CPU, e.g.
> during a page fault.
>
> Without this change, TTM could evict other BOs while trying to satisfy
> the requested placement, even if the evicted BOs were outside of the
> requested placement range. Doing so didn't free up any space in the
> requested placement range, so the (potentially high) eviction cost was
> incurred for no benefit.
>
> Nominating for stable because radeon driver changes in 3.17 made this
> much more noticeable than before.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=84662
> Signed-off-by: Michel Dänzer <[email protected]>
> Signed-off-by: Alex Deucher <[email protected]>
> ---
>
> This is a backport of commit e300180f71037fd9ed1ca967006fd9f3ee466bcd for
> the 3.17 and older stable branches.
>
Thank you Michel, I'll queue this backport for the 3.16 kernel.
Cheers,
--
Luís
> drivers/gpu/drm/ttm/ttm_bo.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 3da89d5..e25845e 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -716,6 +716,7 @@ out:
>
> static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
> uint32_t mem_type,
> + const struct ttm_placement *placement,
> bool interruptible,
> bool no_wait_gpu)
> {
> @@ -727,8 +728,22 @@ 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(bo, false, true, false, NULL);
> - if (!ret)
> + if (!ret) {
> + if (placement && (placement->fpfn || placement->lpfn)) {
> + /* Don't evict this BO if it's outside of the
> + * requested placement range
> + */
> + if (placement->fpfn >= (bo->mem.start +
> bo->mem.size) ||
> + (placement->lpfn &&
> + placement->lpfn <= bo->mem.start)) {
> + __ttm_bo_unreserve(bo);
> + ret = -EBUSY;
> + continue;
> + }
> + }
> +
> break;
> + }
> }
>
> if (ret) {
> @@ -789,7 +804,7 @@ static int ttm_bo_mem_force_space(struct
> ttm_buffer_object *bo,
> return ret;
> if (mem->mm_node)
> break;
> - ret = ttm_mem_evict_first(bdev, mem_type,
> + ret = ttm_mem_evict_first(bdev, mem_type, placement,
> interruptible, no_wait_gpu);
> if (unlikely(ret != 0))
> return ret;
> @@ -1245,7 +1260,7 @@ static int ttm_bo_force_list_clean(struct ttm_bo_device
> *bdev,
> spin_lock(&glob->lru_lock);
> while (!list_empty(&man->lru)) {
> spin_unlock(&glob->lru_lock);
> - ret = ttm_mem_evict_first(bdev, mem_type, false, false);
> + ret = ttm_mem_evict_first(bdev, mem_type, NULL, false, false);
> if (ret) {
> if (allow_errors) {
> return ret;
> --
> 2.1.3
>
> --
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