On Fri, 21 May 2021 at 16:33, Thomas Hellström thomas.hellstrom@linux.intel.com wrote:
If the bo is idle when calling ttm_bo_pipeline_gutting(), we unnecessarily create a ghost object and push it out to delayed destroy. Fix this by adding a path for idle, and document the function.
Also avoid having the bo end up in a bad state vulnerable to user-space triggered kernel BUGs if the call to ttm_tt_create() fails.
Finally reuse ttm_bo_pipeline_gutting() in ttm_bo_evict().
Cc: Christian König christian.koenig@amd.com Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com
drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++------ drivers/gpu/drm/ttm/ttm_bo_util.c | 52 ++++++++++++++++++++++++++++--- drivers/gpu/drm/ttm/ttm_tt.c | 5 +++ include/drm/ttm/ttm_tt.h | 10 ++++++ 4 files changed, 73 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index ca1b098b6a56..a8fa3375b8aa 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -501,10 +501,15 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bdev->funcs->evict_flags(bo, &placement);
if (!placement.num_placement && !placement.num_busy_placement) {
ttm_bo_wait(bo, false, false);
ret = ttm_bo_wait(bo, true, false);if (ret)return ret;
ttm_bo_cleanup_memtype_use(bo);return ttm_tt_create(bo, false);
/** Since we've already synced, this frees backing store* immediately.*/return ttm_bo_pipeline_gutting(bo); } ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx);@@ -974,13 +979,8 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, /* * Remove the backing store if no placement is given. */
if (!placement->num_placement && !placement->num_busy_placement) {ret = ttm_bo_pipeline_gutting(bo);if (ret)return ret;return ttm_tt_create(bo, false);}
if (!placement->num_placement && !placement->num_busy_placement)return ttm_bo_pipeline_gutting(bo); /* * Check whether we need to move buffer.diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 4a7d3d672f9a..7fa9b3a852eb 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -585,26 +585,70 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo, } EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
+/**
- ttm_bo_pipeline_gutting - purge the contents of a bo
- @bo: The buffer object
- Purge the contents of a bo, async if the bo is not idle.
- After a successful call, the bo is left unpopulated in
- system placement. The function may wait uninterruptible
- for idle on OOM.
- Return: 0 if successful, negative error code on failure.
- */
int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo) { static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM }; struct ttm_buffer_object *ghost;
struct ttm_tt *ttm; int ret;
ret = ttm_buffer_object_transfer(bo, &ghost);
/* If already idle, no need for ghost object dance. */ret = ttm_bo_wait(bo, false, true);if (ret != -EBUSY) {if (!bo->ttm) {ret = ttm_tt_create(bo, true);
Why do we now unconditionally add clearing? Below also.
if (ret)return ret;} else {ttm_tt_unpopulate(bo->bdev, bo->ttm);if (bo->type == ttm_bo_type_device)ttm_tt_mark_for_clear(bo->ttm);}ttm_resource_free(bo, &bo->mem);ttm_resource_alloc(bo, &sys_mem, &bo->mem);return 0;}/** We need an unpopulated ttm_tt after giving our current one,* if any, to the ghost object. And we can't afford to fail* creating one *after* the operation.*/ttm = bo->ttm;bo->ttm = NULL;ret = ttm_tt_create(bo, true);swap(bo->ttm, ttm); if (ret) return ret;ret = ttm_buffer_object_transfer(bo, &ghost);if (ret) {ttm_tt_destroy(bo->bdev, ttm);return ret;}ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv); /* Last resort, wait for the BO to be idle when we are OOM */ if (ret) ttm_bo_wait(bo, false, false);
ttm_resource_alloc(bo, &sys_mem, &bo->mem);bo->ttm = NULL;dma_resv_unlock(&ghost->base._resv); ttm_bo_put(ghost);
bo->ttm = ttm;ttm_resource_alloc(bo, &sys_mem, &bo->mem); return 0;} diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 0e41227116b1..913b330a234b 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -134,6 +134,11 @@ void ttm_tt_destroy_common(struct ttm_device *bdev, struct ttm_tt *ttm) } EXPORT_SYMBOL(ttm_tt_destroy_common);
+void ttm_tt_mark_for_clear(struct ttm_tt *ttm) +{
ttm->page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC;+}
void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm) { bdev->funcs->ttm_tt_destroy(bdev, ttm); diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h index 3102059db726..daa9c4cf48bb 100644 --- a/include/drm/ttm/ttm_tt.h +++ b/include/drm/ttm/ttm_tt.h @@ -170,6 +170,16 @@ int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_oper */ void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm);
+/**
- ttm_tt_mark_for_clear - Mark pages for clearing on populate.
- @ttm: Pointer to the ttm_tt structure
- Marks pages for clearing so that the next time the page vector is
- populated, the pages will be cleared.
- */
+void ttm_tt_mark_for_clear(struct ttm_tt *ttm);
void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
2.31.1
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