Am 26.05.21 um 13:32 schrieb Thomas Hellström:
We are calling the eviction_valuable driver callback at eviction time to determine whether we actually can evict a buffer object. The upcoming i915 TTM backend needs the same functionality for swapout, and that might actually be beneficial to other drivers as well.
Add an eviction_valuable call also in the swapout path. Try to keep the current behaviour for all drivers by returning true if the buffer object is already in the TTM_PL_SYSTEM placement. We change behaviour for the case where a buffer object is in a TT backed placement when swapped out, in which case the drivers normal eviction_valuable path is run.
Finally make sure we don't try to swapout a bo that was recently purged and therefore unpopulated.
Reviewed-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Christian König christian.koenig@amd.com Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com
v3:
- Don't export ttm_tt_unpopulate
- Fix confusion reading the locked pointer instead of the value pointed to in ttm_bo_evict_swapout_allowable (Reported by Maarten Lankhorst)
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 +++ drivers/gpu/drm/ttm/ttm_bo.c | 43 ++++++++++++++++--------- drivers/gpu/drm/ttm/ttm_tt.c | 3 ++ 3 files changed, 34 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 3bc3aebfef7c..45d194bffc3f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -1348,6 +1348,10 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, struct dma_fence *f; int i;
- /* Swapout? */
- if (bo->mem.mem_type == TTM_PL_SYSTEM)
return true;- if (bo->type == ttm_bo_type_kernel && !amdgpu_vm_evictable(ttm_to_amdgpu_bo(bo))) return false;
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index be0406466460..1b2d062266ed 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -536,6 +536,10 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, const struct ttm_place *place) {
- dma_resv_assert_held(bo->base.resv);
- if (bo->mem.mem_type == TTM_PL_SYSTEM)
return true;- /* Don't evict this BO if it's outside of the
*/
- requested placement range
@@ -558,7 +562,9 @@ EXPORT_SYMBOL(ttm_bo_eviction_valuable);
- b. Otherwise, trylock it.
*/ static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
struct ttm_operation_ctx *ctx, bool *locked, bool *busy)
struct ttm_operation_ctx *ctx,const struct ttm_place *place,bool *locked, bool *busy)@@ -576,6 +582,14 @@ static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo, *busy = !ret; }
- if (ret && place && !bo->bdev->funcs->eviction_valuable(bo, place)) {
ret = false;if (*locked) {dma_resv_unlock(bo->base.resv);*locked = false;}- }
- return ret; }
@@ -630,20 +644,14 @@ int ttm_mem_evict_first(struct ttm_device *bdev, list_for_each_entry(bo, &man->lru[i], lru) { bool busy;
if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,&busy)) {
if (!ttm_bo_evict_swapout_allowable(bo, ctx, place,&locked, &busy)) { if (busy && !busy_bo && ticket != dma_resv_locking_ctx(bo->base.resv)) busy_bo = bo; continue; }
if (place && !bdev->funcs->eviction_valuable(bo,place)) {if (locked)dma_resv_unlock(bo->base.resv);continue;} if (!ttm_bo_get_unless_zero(bo)) { if (locked) dma_resv_unlock(bo->base.resv);@@ -1140,10 +1148,18 @@ EXPORT_SYMBOL(ttm_bo_wait); int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx, gfp_t gfp_flags) {
- struct ttm_place place = {}; bool locked; int ret;
- if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked, NULL))
/*
* While the bo may already reside in SYSTEM placement, set* SYSTEM as new placement to cover also the move further below.* The driver may use the fact that we're moving from SYSTEM* as an indication that we're about to swap out.*/place.mem_type = TTM_PL_SYSTEM;
if (!ttm_bo_evict_swapout_allowable(bo, ctx, &place, &locked, NULL)) return -EBUSY;
if (!ttm_bo_get_unless_zero(bo)) {
@@ -1168,12 +1184,7 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx, if (bo->mem.mem_type != TTM_PL_SYSTEM) { struct ttm_operation_ctx ctx = { false, false }; struct ttm_resource evict_mem;
struct ttm_place place, hop;memset(&place, 0, sizeof(place));memset(&hop, 0, sizeof(hop));place.mem_type = TTM_PL_SYSTEM;
struct ttm_place hop = {};
I would stick with memset because of the padding reasons.
ret = ttm_resource_alloc(bo, &place, &evict_mem); if (unlikely(ret))diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 913b330a234b..d9793cbb6d13 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -263,6 +263,9 @@ int ttm_tt_swapout(struct ttm_device *bdev, struct ttm_tt *ttm, struct page *to_page; int i, ret;
- if (!ttm_tt_is_populated(ttm))
return 0;
This here is just because of a bug in the higher level function.
I've just pushed the fix for that to drm-misc-fixes, so maybe drop that here as soon as this is backmerged.
Apart from that patch looks good to me.
Christian.
swap_storage = shmem_file_setup("ttm swap", size, 0); if (IS_ERR(swap_storage)) { pr_err("Failed allocating swap storage\n");