[PATCH 4/6] drm/ttm: add the infrastructur for pipelined evictions
Christian König
deathsimple at vodafone.de
Wed Jun 15 11:44:03 UTC 2016
From: Christian König <christian.koenig at amd.com>
Free up the memory immediately, remember the last eviction for each domain and
make new allocations depend on the last eviction to be completed.
Signed-off-by: Christian König <christian.koenig at amd.com>
---
drivers/gpu/drm/ttm/ttm_bo.c | 49 ++++++++++++++++++---
drivers/gpu/drm/ttm/ttm_bo_util.c | 92 +++++++++++++++++++++++++++++++++++++++
include/drm/ttm/ttm_bo_driver.h | 24 ++++++++++
3 files changed, 160 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 28cd535..5d93169 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -788,6 +788,34 @@ void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem)
EXPORT_SYMBOL(ttm_bo_mem_put);
/**
+ * Add the last move fence to the BO and reserve a new shared slot.
+ */
+static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
+ struct ttm_mem_type_manager *man,
+ struct ttm_mem_reg *mem)
+{
+ struct fence *fence;
+ int ret;
+
+ spin_lock(&man->move_lock);
+ fence = fence_get(man->move);
+ spin_unlock(&man->move_lock);
+
+ if (fence) {
+ reservation_object_add_shared_fence(bo->resv, fence);
+
+ ret = reservation_object_reserve_shared(bo->resv);
+ if (unlikely(ret))
+ return ret;
+
+ fence_put(bo->moving);
+ bo->moving = fence;
+ }
+
+ return 0;
+}
+
+/**
* Repeatedly evict memory from the LRU for @mem_type until we create enough
* space, or we've evicted everything and there isn't enough space.
*/
@@ -813,10 +841,8 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
if (unlikely(ret != 0))
return ret;
} while (1);
- if (mem->mm_node == NULL)
- return -ENOMEM;
mem->mem_type = mem_type;
- return 0;
+ return ttm_bo_add_move_fence(bo, man, mem);
}
static uint32_t ttm_bo_select_caching(struct ttm_mem_type_manager *man,
@@ -886,6 +912,10 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
bool has_erestartsys = false;
int i, ret;
+ ret = reservation_object_reserve_shared(bo->resv);
+ if (unlikely(ret))
+ return ret;
+
mem->mm_node = NULL;
for (i = 0; i < placement->num_placement; ++i) {
const struct ttm_place *place = &placement->placement[i];
@@ -919,9 +949,15 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
ret = (*man->func->get_node)(man, bo, place, mem);
if (unlikely(ret))
return ret;
-
- if (mem->mm_node)
+
+ if (mem->mm_node) {
+ ret = ttm_bo_add_move_fence(bo, man, mem);
+ if (unlikely(ret)) {
+ (*man->func->put_node)(man, mem);
+ return ret;
+ }
break;
+ }
}
if ((type_ok && (mem_type == TTM_PL_SYSTEM)) || mem->mm_node) {
@@ -1290,6 +1326,7 @@ int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type)
mem_type);
return ret;
}
+ fence_put(man->move);
man->use_type = false;
man->has_type = false;
@@ -1335,6 +1372,7 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
man->io_reserve_fastpath = true;
man->use_io_reserve_lru = false;
mutex_init(&man->io_reserve_mutex);
+ spin_lock_init(&man->move_lock);
INIT_LIST_HEAD(&man->io_reserve_lru);
ret = bdev->driver->init_mem_type(bdev, type, man);
@@ -1353,6 +1391,7 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
man->size = p_size;
INIT_LIST_HEAD(&man->lru);
+ man->move = NULL;
return 0;
}
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 9ea8d02..0c389a5 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -696,3 +696,95 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
return 0;
}
EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
+
+int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
+ struct fence *fence, bool evict,
+ struct ttm_mem_reg *new_mem)
+{
+ struct ttm_bo_device *bdev = bo->bdev;
+ struct ttm_mem_reg *old_mem = &bo->mem;
+
+ struct ttm_mem_type_manager *from = &bdev->man[old_mem->mem_type];
+ struct ttm_mem_type_manager *to = &bdev->man[new_mem->mem_type];
+
+ int ret;
+
+ reservation_object_add_excl_fence(bo->resv, fence);
+
+ if (!evict) {
+ struct ttm_buffer_object *ghost_obj;
+
+ /**
+ * This should help pipeline ordinary buffer moves.
+ *
+ * Hang old buffer memory on a new buffer object,
+ * and leave it to be released when the GPU
+ * operation has completed.
+ */
+
+ fence_put(bo->moving);
+ bo->moving = fence_get(fence);
+
+ ret = ttm_buffer_object_transfer(bo, &ghost_obj);
+ if (ret)
+ return ret;
+
+ reservation_object_add_excl_fence(ghost_obj->resv, fence);
+
+ /**
+ * If we're not moving to fixed memory, the TTM object
+ * needs to stay alive. Otherwhise hang it on the ghost
+ * bo to be unbound and destroyed.
+ */
+
+ if (!(to->flags & TTM_MEMTYPE_FLAG_FIXED))
+ ghost_obj->ttm = NULL;
+ else
+ bo->ttm = NULL;
+
+ ttm_bo_unreserve(ghost_obj);
+ ttm_bo_unref(&ghost_obj);
+
+ } else if (from->flags & TTM_MEMTYPE_FLAG_FIXED) {
+
+ /**
+ * BO doesn't have a TTM we need to bind/unbind. Just remember
+ * this eviction and free up the allocation
+ */
+
+ spin_lock(&from->move_lock);
+ if (!from->move || fence_is_later(from->move, fence)) {
+ fence_put(from->move);
+ from->move = fence_get(fence);
+ }
+ spin_unlock(&from->move_lock);
+
+ ttm_bo_free_old_node(bo);
+
+ fence_put(bo->moving);
+ bo->moving = fence_get(fence);
+
+ } else {
+ /**
+ * Last resort, wait for the move to be completed.
+ *
+ * Should never happen in pratice.
+ */
+
+ ret = ttm_bo_wait(bo, false, false);
+ if (ret)
+ return ret;
+
+ if (to->flags & TTM_MEMTYPE_FLAG_FIXED) {
+ ttm_tt_destroy(bo->ttm);
+ bo->ttm = NULL;
+ }
+ ttm_bo_free_old_node(bo);
+ }
+
+ *old_mem = *new_mem;
+ new_mem->mm_node = NULL;
+
+ return 0;
+}
+EXPORT_SYMBOL(ttm_bo_pipeline_move);
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 44dea22..e2ebe66 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -258,8 +258,10 @@ struct ttm_mem_type_manager_func {
* reserved by the TTM vm system.
* @io_reserve_lru: Optional lru list for unreserving io mem regions.
* @io_reserve_fastpath: Only use bdev::driver::io_mem_reserve to obtain
+ * @move_lock: lock for move fence
* static information. bdev::driver::io_mem_free is never used.
* @lru: The lru list for this memory type.
+ * @move: The fence of the last pipelined move operation.
*
* This structure is used to identify and manage memory types for a device.
* It's set up by the ttm_bo_driver::init_mem_type method.
@@ -286,6 +288,7 @@ struct ttm_mem_type_manager {
struct mutex io_reserve_mutex;
bool use_io_reserve_lru;
bool io_reserve_fastpath;
+ spinlock_t move_lock;
/*
* Protected by @io_reserve_mutex:
@@ -298,6 +301,11 @@ struct ttm_mem_type_manager {
*/
struct list_head lru;
+
+ /*
+ * Protected by @move_lock.
+ */
+ struct fence *move;
};
/**
@@ -1014,6 +1022,22 @@ extern void ttm_bo_free_old_node(struct ttm_buffer_object *bo);
extern int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
struct fence *fence, bool evict,
struct ttm_mem_reg *new_mem);
+
+/**
+ * ttm_bo_pipeline_move.
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ * @fence: A fence object that signals when moving is complete.
+ * @evict: This is an evict move. Don't return until the buffer is idle.
+ * @new_mem: struct ttm_mem_reg indicating where to move.
+ *
+ * Function for pipelining accelerated moves. Either free the memory
+ * immediately or hang it on a temporary buffer object.
+ */
+int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
+ struct fence *fence, bool evict,
+ struct ttm_mem_reg *new_mem);
+
/**
* ttm_io_prot
*
--
2.5.0
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