Rework the TTM swapping to use the LRU walker helper.
This helps fixing up the ttm_bo_swapout() interface
to be consistent about not requiring any locking.
For now mimic the current behaviour of using trylock
only. We could be using ticket-locks here but defer
that until it's deemed necessary. The TTM swapout
functionality is a bit weird anyway since it
alternates between memory types without exhausting
TTM_PL_SYSTEM first.
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Somalapuram Amaranath <Amaranath.Somalapuram@xxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx>
v6:
- Improve on error code translation in the swapout callback
(Matthew Brost).
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 111 ++++++++++++++++++++-----------
drivers/gpu/drm/ttm/ttm_device.c | 30 ++-------
include/drm/ttm/ttm_bo.h | 5 +-
3 files changed, 82 insertions(+), 64 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 43eda720657f..1053cdca131e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1118,11 +1118,23 @@ int ttm_bo_wait_ctx(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx)
}
EXPORT_SYMBOL(ttm_bo_wait_ctx);
-int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
- gfp_t gfp_flags)
+/**
+ * struct ttm_bo_swapout_walk - Parameters for the swapout walk
+ */
+struct ttm_bo_swapout_walk {
+ /** @walk: The walk base parameters. */
+ struct ttm_lru_walk walk;
+ /** @gfp_flags: The gfp flags to use for ttm_tt_swapout() */
+ gfp_t gfp_flags;
+};
+
+static long
+ttm_bo_swapout_cb(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo)
{
- struct ttm_place place;
- bool locked;
+ struct ttm_place place = {.mem_type = bo->resource->mem_type};
+ struct ttm_bo_swapout_walk *swapout_walk =
+ container_of(walk, typeof(*swapout_walk), walk);
+ struct ttm_operation_ctx *ctx = walk->ctx;
long ret;
/*
@@ -1131,28 +1143,29 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
* 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 = bo->resource->mem_type;
- if (!ttm_bo_evict_swapout_allowable(bo, ctx, &place, &locked, NULL))
- return -EBUSY;
+ if (!bo->bdev->funcs->eviction_valuable(bo, &place)) {
+ ret = -EBUSY;
+ goto out;
+ }
if (!bo->ttm || !ttm_tt_is_populated(bo->ttm) ||
bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL ||
- bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED ||
- !ttm_bo_get_unless_zero(bo)) {
- if (locked)
- dma_resv_unlock(bo->base.resv);
- return -EBUSY;
+ bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED) {
+ ret = -EBUSY;
+ goto out;
}
if (bo->deleted) {
- ret = ttm_bo_cleanup_refs(bo, false, false, locked);
- ttm_bo_put(bo);
- return ret == -EBUSY ? -ENOSPC : ret;
- }
+ pgoff_t num_pages = bo->ttm->num_pages;
- /* TODO: Cleanup the locking */
- spin_unlock(&bo->bdev->lru_lock);
+ ret = ttm_bo_wait_ctx(bo, ctx);
+ if (ret)
+ goto out;
+
+ ttm_bo_cleanup_memtype_use(bo);
+ ret = num_pages;
+ goto out;
+ }
/*
* Move to system cached
@@ -1164,12 +1177,13 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
memset(&hop, 0, sizeof(hop));
place.mem_type = TTM_PL_SYSTEM;
ret = ttm_resource_alloc(bo, &place, &evict_mem);
- if (unlikely(ret))
+ if (ret)
goto out;
ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
- if (unlikely(ret != 0)) {
- WARN(ret == -EMULTIHOP, "Unexpected multihop in swaput - likely driver bug.\n");
+ if (ret) {
+ WARN(ret == -EMULTIHOP,
+ "Unexpected multihop in swapout - likely driver bug.\n");
ttm_resource_free(bo, &evict_mem);
goto out;
}
@@ -1179,30 +1193,53 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
* Make sure BO is idle.
*/
ret = ttm_bo_wait_ctx(bo, ctx);
- if (unlikely(ret != 0))
+ if (ret)
goto out;
ttm_bo_unmap_virtual(bo);
-
- /*
- * Swap out. Buffer will be swapped in again as soon as
- * anyone tries to access a ttm page.
- */
if (bo->bdev->funcs->swap_notify)
bo->bdev->funcs->swap_notify(bo);
if (ttm_tt_is_populated(bo->ttm))
- ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
+ ret = ttm_tt_swapout(bo->bdev, bo->ttm, swapout_walk->gfp_flags);
out:
+ /* Consider -ENOMEM and -ENOSPC non-fatal. */
+ if (ret == -ENOMEM || ret == -ENOSPC)
+ ret = -EBUSY;
- /*
- * Unreserve without putting on LRU to avoid swapping out an
- * already swapped buffer.
- */
- if (locked)
- dma_resv_unlock(bo->base.resv);
- ttm_bo_put(bo);
- return ret == -EBUSY ? -ENOSPC : ret;
+ return ret;
+}
+
+const struct ttm_lru_walk_ops ttm_swap_ops = {
+ .process_bo = ttm_bo_swapout_cb,
+};
+
+/**
+ * ttm_bo_swapout() - Swap out buffer objects on the LRU list to shmem.
+ * @bdev: The ttm device.
+ * @ctx: The ttm_operation_ctx governing the swapout operation.
+ * @man: The resource manager whose resources / buffer objects are
+ * goint to be swapped out.
+ * @gfp_flags: The gfp flags used for shmem page allocations.
+ * @target: The desired number of pages to swap out.
+ *
+ * Return: The number of pages actually swapped out, or negative error code
+ * on error.
+ */
+long ttm_bo_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
+ struct ttm_resource_manager *man, gfp_t gfp_flags,
+ pgoff_t target)
+{
+ struct ttm_bo_swapout_walk swapout_walk = {
+ .walk = {
+ .ops = &ttm_swap_ops,
+ .ctx = ctx,
+ .trylock_only = true,
+ },
+ .gfp_flags = gfp_flags,
+ };
+
+ return ttm_lru_walk_for_evict(&swapout_walk.walk, bdev, man, target);
}
void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index f9e9b1ec8c8a..ee575d8a54c0 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -148,40 +148,20 @@ int ttm_global_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
gfp_t gfp_flags)
{
- struct ttm_resource_cursor cursor;
struct ttm_resource_manager *man;
- struct ttm_resource *res;
unsigned i;
- int ret;
+ long lret;
- spin_lock(&bdev->lru_lock);
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {
man = ttm_manager_type(bdev, i);
if (!man || !man->use_tt)
continue;
- ttm_resource_manager_for_each_res(man, &cursor, res) {
- struct ttm_buffer_object *bo = res->bo;
- uint32_t num_pages;
-
- if (!bo || bo->resource != res)
- continue;
-
- num_pages = PFN_UP(bo->base.size);
- ret = ttm_bo_swapout(bo, ctx, gfp_flags);
- /* ttm_bo_swapout has dropped the lru_lock */
- if (!ret) {
- ttm_resource_cursor_fini(&cursor);
- return num_pages;
- }
- if (ret != -EBUSY) {
- ttm_resource_cursor_fini(&cursor);
- return ret;
- }
- }
+ lret = ttm_bo_swapout(bdev, ctx, man, gfp_flags, 1);
+ /* Can be both positive (num_pages) and negative (error) */
+ if (lret)
+ return lret;
}
- ttm_resource_cursor_fini_locked(&cursor);
- spin_unlock(&bdev->lru_lock);
return 0;
}
EXPORT_SYMBOL(ttm_device_swapout);
diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
index 10bff3aecd5c..de97ea9fa75f 100644
--- a/include/drm/ttm/ttm_bo.h
+++ b/include/drm/ttm/ttm_bo.h
@@ -417,8 +417,9 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map);
void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map);
int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
-int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
- gfp_t gfp_flags);
+long ttm_bo_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
+ struct ttm_resource_manager *man, gfp_t gfp_flags,
+ pgoff_t target);
void ttm_bo_pin(struct ttm_buffer_object *bo);
void ttm_bo_unpin(struct ttm_buffer_object *bo);
int ttm_mem_evict_first(struct ttm_device *bdev,
--
2.44.0
