[PATCH v2 1/7] drm/xe: use backup object for pinned save/restore
K V P, Satyanarayana
satyanarayana.k.v.p at intel.com
Thu Jan 23 07:39:34 UTC 2025
> -----Original Message-----
> From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of
> Matthew Auld
> Sent: Wednesday, December 18, 2024 5:49 PM
> To: intel-xe at lists.freedesktop.org
> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>; Brost, Matthew
> <matthew.brost at intel.com>
> Subject: [PATCH v2 1/7] drm/xe: use backup object for pinned save/restore
>
> Currently we move pinned objects, relying on the fact that the lpfn/fpfn
> will force the placement to occupy the same pages when restoring.
> However this then limits all such pinned objects to be contig
> underneath. In addition it is likely a little fragile moving pinned
> objects in the first place. Rather than moving such objects rather copy
> the page contents to a secondary system memory object, that way the VRAM
> pages never move and remain pinned. This also opens the door for
> eventually having non-contig pinned objects that can also be
> saved/restored using blitter.
>
> v2:
> - Make sure to drop the fence ref.
> - Handle NULL bo->migrate.
>
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1182
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Cc: Matthew Brost <matthew.brost at intel.com>
> ---
> drivers/gpu/drm/xe/xe_bo.c | 293 +++++++++++++++----------------
> drivers/gpu/drm/xe/xe_bo_evict.c | 8 -
> drivers/gpu/drm/xe/xe_bo_types.h | 2 +
> 3 files changed, 144 insertions(+), 159 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index e6c896ad5602..fa2d74a56283 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -780,79 +780,44 @@ static int xe_bo_move(struct ttm_buffer_object
> *ttm_bo, bool evict,
> xe_pm_runtime_get_noresume(xe);
> }
>
> - if (xe_bo_is_pinned(bo) && !xe_bo_is_user(bo)) {
> - /*
> - * Kernel memory that is pinned should only be moved on
> suspend
> - * / resume, some of the pinned memory is required for the
> - * device to resume / use the GPU to move other evicted
> memory
> - * (user memory) around. This likely could be optimized a bit
> - * futher where we find the minimum set of pinned memory
> - * required for resume but for simplity doing a memcpy for all
> - * pinned memory.
> - */
> - ret = xe_bo_vmap(bo);
> - if (!ret) {
> - ret = ttm_bo_move_memcpy(ttm_bo, ctx,
> new_mem);
> -
> - /* Create a new VMAP once kernel BO back in VRAM
> */
> - if (!ret && resource_is_vram(new_mem)) {
> - struct xe_mem_region *vram =
> res_to_mem_region(new_mem);
> - void __iomem *new_addr = vram->mapping +
> - (new_mem->start << PAGE_SHIFT);
> -
> - if (XE_WARN_ON(new_mem->start ==
> XE_BO_INVALID_OFFSET)) {
> - ret = -EINVAL;
> - xe_pm_runtime_put(xe);
> - goto out;
> - }
> -
> - xe_assert(xe, new_mem->start ==
> - bo->placements->fpfn);
> -
> - iosys_map_set_vaddr_iomem(&bo->vmap,
> new_addr);
> - }
> - }
> - } else {
> - if (move_lacks_source) {
> - u32 flags = 0;
> + if (move_lacks_source) {
> + u32 flags = 0;
>
> - if (mem_type_is_vram(new_mem->mem_type))
> - flags |= XE_MIGRATE_CLEAR_FLAG_FULL;
> - else if (handle_system_ccs)
> - flags |=
> XE_MIGRATE_CLEAR_FLAG_CCS_DATA;
> + if (mem_type_is_vram(new_mem->mem_type))
> + flags |= XE_MIGRATE_CLEAR_FLAG_FULL;
> + else if (handle_system_ccs)
> + flags |= XE_MIGRATE_CLEAR_FLAG_CCS_DATA;
>
> - fence = xe_migrate_clear(migrate, bo, new_mem,
> flags);
> - }
> - else
> - fence = xe_migrate_copy(migrate, bo, bo, old_mem,
> - new_mem,
> handle_system_ccs);
> - if (IS_ERR(fence)) {
> - ret = PTR_ERR(fence);
> - xe_pm_runtime_put(xe);
> - goto out;
> - }
> - if (!move_lacks_source) {
> - ret = ttm_bo_move_accel_cleanup(ttm_bo, fence,
> evict,
> - true, new_mem);
> - if (ret) {
> - dma_fence_wait(fence, false);
> - ttm_bo_move_null(ttm_bo, new_mem);
> - ret = 0;
> - }
> - } else {
> - /*
> - * ttm_bo_move_accel_cleanup() may blow up if
> - * bo->resource == NULL, so just attach the
> - * fence and set the new resource.
> - */
> - dma_resv_add_fence(ttm_bo->base.resv, fence,
> - DMA_RESV_USAGE_KERNEL);
> + fence = xe_migrate_clear(migrate, bo, new_mem, flags);
> + } else {
> + fence = xe_migrate_copy(migrate, bo, bo, old_mem,
> new_mem,
> + handle_system_ccs);
> + }
> + if (IS_ERR(fence)) {
> + ret = PTR_ERR(fence);
> + xe_pm_runtime_put(xe);
> + goto out;
> + }
> + if (!move_lacks_source) {
> + ret = ttm_bo_move_accel_cleanup(ttm_bo, fence, evict, true,
> + new_mem);
> + if (ret) {
> + dma_fence_wait(fence, false);
> ttm_bo_move_null(ttm_bo, new_mem);
> + ret = 0;
> }
> -
> - dma_fence_put(fence);
> + } else {
> + /*
> + * ttm_bo_move_accel_cleanup() may blow up if
> + * bo->resource == NULL, so just attach the
> + * fence and set the new resource.
> + */
> + dma_resv_add_fence(ttm_bo->base.resv, fence,
> + DMA_RESV_USAGE_KERNEL);
> + ttm_bo_move_null(ttm_bo, new_mem);
> }
>
> + dma_fence_put(fence);
> xe_pm_runtime_put(xe);
>
> out:
> @@ -884,59 +849,79 @@ static int xe_bo_move(struct ttm_buffer_object
> *ttm_bo, bool evict,
> */
> int xe_bo_evict_pinned(struct xe_bo *bo)
> {
> - struct ttm_place place = {
> - .mem_type = XE_PL_TT,
> - };
> - struct ttm_placement placement = {
> - .placement = &place,
> - .num_placement = 1,
> - };
> - struct ttm_operation_ctx ctx = {
> - .interruptible = false,
> - .gfp_retry_mayfail = true,
> - };
> - struct ttm_resource *new_mem;
> - int ret;
> + struct xe_device *xe = ttm_to_xe_device(bo->ttm.bdev);
> + struct xe_bo *backup;
> + bool unmap = false;
> + int ret = 0;
>
> - xe_bo_assert_held(bo);
> + xe_bo_lock(bo, false);
>
> - if (WARN_ON(!bo->ttm.resource))
> - return -EINVAL;
> + if (WARN_ON(!bo->ttm.resource)) {
> + ret = -EINVAL;
> + goto out_unlock_bo;
> + }
>
> - if (WARN_ON(!xe_bo_is_pinned(bo)))
> - return -EINVAL;
> + if (WARN_ON(!xe_bo_is_pinned(bo))) {
> + ret = -EINVAL;
> + goto out_unlock_bo;
> + }
>
> if (!xe_bo_is_vram(bo))
> - return 0;
> + goto out_unlock_bo;
> +
> + backup = xe_bo_create_locked(xe, NULL, NULL, bo->size,
> ttm_bo_type_kernel,
> + XE_BO_FLAG_SYSTEM |
> XE_BO_FLAG_NEEDS_CPU_ACCESS |
> + XE_BO_FLAG_PINNED);
> + if (IS_ERR(backup)) {
> + ret = PTR_ERR(backup);
> + goto out_unlock_bo;
> + }
>
> - ret = ttm_bo_mem_space(&bo->ttm, &placement, &new_mem,
> &ctx);
> - if (ret)
> - return ret;
> + if (!xe_bo_is_user(bo)) {
> + ret = xe_bo_vmap(backup);
> + if (ret)
> + goto out_backup;
>
> - if (!bo->ttm.ttm) {
> - bo->ttm.ttm = xe_ttm_tt_create(&bo->ttm, 0);
> - if (!bo->ttm.ttm) {
> - ret = -ENOMEM;
> - goto err_res_free;
> + if (iosys_map_is_null(&bo->vmap)) {
> + ret = xe_bo_vmap(bo);
> + if (ret)
> + goto out_backup;
> + unmap = true;
> }
> - }
>
> - ret = ttm_bo_populate(&bo->ttm, &ctx);
> - if (ret)
> - goto err_res_free;
> + xe_map_memcpy_from(xe, backup->vmap.vaddr, &bo-
> >vmap, 0,
> + bo->size);
> + } else {
> + struct xe_migrate *migrate;
> + struct dma_fence *fence;
>
> - ret = dma_resv_reserve_fences(bo->ttm.base.resv, 1);
> - if (ret)
> - goto err_res_free;
> + if (bo->tile)
> + migrate = bo->tile->migrate;
> + else
> + migrate = mem_type_to_migrate(xe, bo-
> >ttm.resource->mem_type);
>
> - ret = xe_bo_move(&bo->ttm, false, &ctx, new_mem, NULL);
> - if (ret)
> - goto err_res_free;
> + fence = xe_migrate_copy(migrate, bo, backup,
> + bo->ttm.resource, backup-
> >ttm.resource,
> + false);
> + if (IS_ERR(fence)) {
> + ret = PTR_ERR(fence);
> + goto out_backup;
> + }
>
> - return 0;
> + dma_fence_put(fence);
> + }
>
> -err_res_free:
> - ttm_resource_free(&bo->ttm, &new_mem);
> + bo->backup_obj = backup;
> +
> +out_backup:
> + xe_bo_vunmap(backup);
> + xe_bo_unlock(backup);
> + if (ret)
> + xe_bo_put(backup);
> +out_unlock_bo:
> + if (unmap)
> + xe_bo_vunmap(bo);
> + xe_bo_unlock(bo);
> return ret;
> }
>
> @@ -957,47 +942,69 @@ int xe_bo_restore_pinned(struct xe_bo *bo)
> .interruptible = false,
> .gfp_retry_mayfail = false,
> };
> - struct ttm_resource *new_mem;
> - struct ttm_place *place = &bo->placements[0];
> + struct xe_device *xe = ttm_to_xe_device(bo->ttm.bdev);
> + struct xe_bo *backup = bo->backup_obj;
> + bool unmap = false;
> int ret;
>
> - xe_bo_assert_held(bo);
> + if (!backup)
> + return 0;
>
> - if (WARN_ON(!bo->ttm.resource))
> - return -EINVAL;
> + xe_bo_lock(backup, false);
>
> - if (WARN_ON(!xe_bo_is_pinned(bo)))
> - return -EINVAL;
> + ret = ttm_bo_validate(&backup->ttm, &backup->placement, &ctx);
> + if (ret)
> + goto out_backup;
>
> - if (WARN_ON(xe_bo_is_vram(bo)))
> - return -EINVAL;
> + if (WARN_ON(!dma_resv_trylock(bo->ttm.base.resv))) {
> + ret = -EBUSY;
> + goto out_backup;
> + }
>
> - if (WARN_ON(!bo->ttm.ttm && !xe_bo_is_stolen(bo)))
> - return -EINVAL;
> + if (!xe_bo_is_user(bo)) {
> + ret = xe_bo_vmap(backup);
> + if (ret)
> + goto out_unlock_bo;
>
> - if (!mem_type_is_vram(place->mem_type))
> - return 0;
> + if (iosys_map_is_null(&bo->vmap)) {
> + ret = xe_bo_vmap(bo);
> + if (ret)
> + goto out_unlock_bo;
> + unmap = true;
> + }
>
> - ret = ttm_bo_mem_space(&bo->ttm, &bo->placement, &new_mem,
> &ctx);
> - if (ret)
> - return ret;
> + xe_map_memcpy_to(xe, &bo->vmap, 0, backup-
> >vmap.vaddr,
> + bo->size);
> + } else {
> + struct xe_migrate *migrate;
> + struct dma_fence *fence;
>
> - ret = ttm_bo_populate(&bo->ttm, &ctx);
> - if (ret)
> - goto err_res_free;
> + if (bo->tile)
> + migrate = bo->tile->migrate;
> + else
> + migrate = mem_type_to_migrate(xe, bo-
> >ttm.resource->mem_type);
>
> - ret = dma_resv_reserve_fences(bo->ttm.base.resv, 1);
> - if (ret)
> - goto err_res_free;
> + fence = xe_migrate_copy(migrate, backup, bo,
> + backup->ttm.resource, bo-
> >ttm.resource,
> + false);
> + if (IS_ERR(fence)) {
> + ret = PTR_ERR(fence);
> + goto out_unlock_bo;
> + }
>
> - ret = xe_bo_move(&bo->ttm, false, &ctx, new_mem, NULL);
> - if (ret)
> - goto err_res_free;
> + dma_fence_put(fence);
> + }
>
> - return 0;
> + bo->backup_obj = NULL;
>
> -err_res_free:
> - ttm_resource_free(&bo->ttm, &new_mem);
> +out_unlock_bo:
> + xe_bo_unlock(bo);
> +out_backup:
> + if (unmap)
> + xe_bo_vunmap(backup);
> + xe_bo_unlock(backup);
> + if (!bo->backup_obj)
> + xe_bo_put(backup);
> return ret;
> }
>
> @@ -1921,22 +1928,6 @@ int xe_bo_pin(struct xe_bo *bo)
> if (err)
> return err;
>
> - /*
> - * For pinned objects in on DGFX, which are also in vram, we expect
> - * these to be in contiguous VRAM memory. Required eviction /
> restore
> - * during suspend / resume (force restore to same physical address).
> - */
> - if (IS_DGFX(xe) && !(IS_ENABLED(CONFIG_DRM_XE_DEBUG) &&
> - bo->flags & XE_BO_FLAG_INTERNAL_TEST)) {
> - if (mem_type_is_vram(place->mem_type)) {
> - xe_assert(xe, place->flags &
> TTM_PL_FLAG_CONTIGUOUS);
> -
> - place->fpfn = (xe_bo_addr(bo, 0, PAGE_SIZE) -
> - vram_region_gpu_offset(bo-
> >ttm.resource)) >> PAGE_SHIFT;
> - place->lpfn = place->fpfn + (bo->size >> PAGE_SHIFT);
> - }
> - }
> -
> if (mem_type_is_vram(place->mem_type) || bo->flags &
> XE_BO_FLAG_GGTT) {
> spin_lock(&xe->pinned.lock);
> list_add_tail(&bo->pinned_link, &xe-
> >pinned.kernel_bo_present);
> diff --git a/drivers/gpu/drm/xe/xe_bo_evict.c
> b/drivers/gpu/drm/xe/xe_bo_evict.c
> index 6a40eedd9db1..96764d8169f4 100644
> --- a/drivers/gpu/drm/xe/xe_bo_evict.c
> +++ b/drivers/gpu/drm/xe/xe_bo_evict.c
> @@ -69,9 +69,7 @@ int xe_bo_evict_all(struct xe_device *xe)
> list_move_tail(&bo->pinned_link, &still_in_list);
> spin_unlock(&xe->pinned.lock);
>
> - xe_bo_lock(bo, false);
> ret = xe_bo_evict_pinned(bo);
> - xe_bo_unlock(bo);
> xe_bo_put(bo);
Any specific reason for removing locks in this function?
> if (ret) {
> spin_lock(&xe->pinned.lock);
> @@ -103,9 +101,7 @@ int xe_bo_evict_all(struct xe_device *xe)
> list_move_tail(&bo->pinned_link, &xe->pinned.evicted);
> spin_unlock(&xe->pinned.lock);
>
> - xe_bo_lock(bo, false);
> ret = xe_bo_evict_pinned(bo);
> - xe_bo_unlock(bo);
> xe_bo_put(bo);
> if (ret)
> return ret;
> @@ -143,9 +139,7 @@ int xe_bo_restore_kernel(struct xe_device *xe)
> list_move_tail(&bo->pinned_link, &xe-
> >pinned.kernel_bo_present);
> spin_unlock(&xe->pinned.lock);
>
> - xe_bo_lock(bo, false);
> ret = xe_bo_restore_pinned(bo);
> - xe_bo_unlock(bo);
> if (ret) {
> xe_bo_put(bo);
> return ret;
> @@ -213,9 +207,7 @@ int xe_bo_restore_user(struct xe_device *xe)
> xe_bo_get(bo);
> spin_unlock(&xe->pinned.lock);
>
> - xe_bo_lock(bo, false);
> ret = xe_bo_restore_pinned(bo);
> - xe_bo_unlock(bo);
> xe_bo_put(bo);
> if (ret) {
> spin_lock(&xe->pinned.lock);
> diff --git a/drivers/gpu/drm/xe/xe_bo_types.h
> b/drivers/gpu/drm/xe/xe_bo_types.h
> index 46dc9e4e3e46..a1f1f637aa87 100644
> --- a/drivers/gpu/drm/xe/xe_bo_types.h
> +++ b/drivers/gpu/drm/xe/xe_bo_types.h
> @@ -27,6 +27,8 @@ struct xe_vm;
> struct xe_bo {
> /** @ttm: TTM base buffer object */
> struct ttm_buffer_object ttm;
> + /** @backup_obj: The backup object when pinned and suspended
> (vram only) */
> + struct xe_bo *backup_obj;
> /** @size: Size of this buffer object */
> size_t size;
> /** @flags: flags for this buffer object */
> --
> 2.47.1
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