From: Thomas Hellström Date: Wed, 2 Jun 2021 08:38:14 +0000 (+0200) Subject: drm/ttm, drm/amdgpu: Allow the driver some control over swapping X-Git-Tag: v5.15~303^2~28^2~229 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=abb50d67adf3f01f567f365b45ecb49df8289296;p=platform%2Fkernel%2Flinux-starfive.git drm/ttm, drm/amdgpu: Allow the driver some control over swapping 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 Cc: Christian König Signed-off-by: Thomas Hellström Acked-by: Christian König 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 --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 53a8ab8..ea26cb5 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -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; diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index c0ca28e..08f8797 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -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: /*