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drm/ttm, drm/amdgpu: Allow the driver some control over swapping

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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.

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>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20210602083818.241793-8-thomas.hellstrom@linux.intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20210602083818.241793-8-thomas.hellstrom@linux.intel.com
This commit is contained in:
Thomas Hellström
2021-06-02 10:38:14 +02:00
parent a3be8cd70f
commit abb50d67ad
2 changed files with 34 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
View File

@@ -1331,6 +1331,10 @@ static bool amdgpu_ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
struct dma_fence *f;
int i;
/* Swapout? */
if (bo->resource->mem_type == TTM_PL_SYSTEM)
return true;
if (bo->type == ttm_bo_type_kernel &&
!amdgpu_vm_evictable(ttm_to_amdgpu_bo(bo)))
return false;

46
drivers/gpu/drm/ttm/ttm_bo.c
View File

@@ -538,6 +538,10 @@ out:
bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
const struct ttm_place *place)
{
dma_resv_assert_held(bo->base.resv);
if (bo->resource->mem_type == TTM_PL_SYSTEM)
return true;
/* Don't evict this BO if it's outside of the
* requested placement range
*/
@@ -560,7 +564,9 @@ 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)
{
bool ret = false;
@@ -578,6 +584,14 @@ 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;
}
@@ -632,20 +646,14 @@ 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);
@@ -1116,10 +1124,19 @@ 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.
*/
memset(&place, 0, sizeof(place));
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)) {
@@ -1144,13 +1161,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
if (bo->resource->mem_type != TTM_PL_SYSTEM) {
struct ttm_operation_ctx ctx = { false, false };
struct ttm_resource *evict_mem;
struct ttm_place place, hop;
struct ttm_place hop;
memset(&place, 0, sizeof(place));
memset(&hop, 0, sizeof(hop));
place.mem_type = TTM_PL_SYSTEM;
ret = ttm_resource_alloc(bo, &place, &evict_mem);
if (unlikely(ret))
goto out;
@@ -1178,7 +1191,8 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
if (bo->bdev->funcs->swap_notify)
bo->bdev->funcs->swap_notify(bo);
ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
if (ttm_tt_is_populated(bo->ttm))
ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
out:
/*