drm/ttm: add ttm_bo_pin()/ttm_bo_unpin() v2

As an alternative to the placement flag add a
pin count to the ttm buffer object.

v2: add dma_resv_assert_help() calls

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.freedesktop.org/patch/391596/?series=81973&rev=1

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index f341532243f1228c6b5edab0363af3cec5c48eb4..ecb93fea50f6fdf525e0d4949f82a09475e38e0e 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -115,7 +115,7 @@ static void ttm_bo_add_mem_to_lru(struct ttm_buffer_object *bo,
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_resource_manager *man;
 
-       if (!list_empty(&bo->lru))
+       if (!list_empty(&bo->lru) || bo->pin_count)
                return;
 
        if (mem->placement & TTM_PL_FLAG_NO_EVICT)
@@ -165,7 +165,8 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
        ttm_bo_del_from_lru(bo);
        ttm_bo_add_mem_to_lru(bo, &bo->mem);
 
-       if (bulk && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
+       if (bulk && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT) &&
+           !bo->pin_count) {
                switch (bo->mem.mem_type) {
                case TTM_PL_TT:
                        ttm_bo_bulk_move_set_pos(&bulk->tt[bo->priority], bo);
@@ -544,8 +545,9 @@ static void ttm_bo_release(struct kref *kref)
                 * shrinkers, now that they are queued for
                 * destruction.
                 */
-               if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT) {
+               if (bo->mem.placement & TTM_PL_FLAG_NO_EVICT || bo->pin_count) {
                        bo->mem.placement &= ~TTM_PL_FLAG_NO_EVICT;
+                       bo->pin_count = 0;
                        ttm_bo_del_from_lru(bo);
                        ttm_bo_add_mem_to_lru(bo, &bo->mem);
                }
@@ -1172,6 +1174,7 @@ int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
        bo->moving = NULL;
        bo->mem.placement = TTM_PL_FLAG_CACHED;
        bo->acc_size = acc_size;
+       bo->pin_count = 0;
        bo->sg = sg;
        if (resv) {
                bo->base.resv = resv;

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index c90133d8a61252f17ff70c4029cdbd8b63a6d6dc..bdee4df1f3f2db464d1d5c77d996b4a4eeec4962 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -352,7 +352,6 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
                return -ENOMEM;
 
        fbo->base = *bo;
-       fbo->base.mem.placement |= TTM_PL_FLAG_NO_EVICT;
 
        ttm_bo_get(bo);
        fbo->bo = bo;
@@ -372,6 +371,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
        kref_init(&fbo->base.kref);
        fbo->base.destroy = &ttm_transfered_destroy;
        fbo->base.acc_size = 0;
+       fbo->base.pin_count = 1;
        if (bo->type != ttm_bo_type_sg)
                fbo->base.base.resv = &fbo->base.base._resv;
 

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index da837d22f78e99e4ca722a4935ea4c63c75513ba..2ff4fdada333487e3aa43dd7884d3c7c11bddcaf 100644 (file)
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -153,6 +153,7 @@ struct ttm_buffer_object {
 
        struct dma_fence *moving;
        unsigned priority;
+       unsigned pin_count;
 
        /**
         * Special members that are protected by the reserve lock
@@ -607,6 +608,31 @@ static inline bool ttm_bo_uses_embedded_gem_object(struct ttm_buffer_object *bo)
        return bo->base.dev != NULL;
 }
 
+/**
+ * ttm_bo_pin - Pin the buffer object.
+ * @bo: The buffer object to pin
+ *
+ * Make sure the buffer is not evicted any more during memory pressure.
+ */
+static inline void ttm_bo_pin(struct ttm_buffer_object *bo)
+{
+       dma_resv_assert_held(bo->base.resv);
+       ++bo->pin_count;
+}
+
+/**
+ * ttm_bo_unpin - Unpin the buffer object.
+ * @bo: The buffer object to unpin
+ *
+ * Allows the buffer object to be evicted again during memory pressure.
+ */
+static inline void ttm_bo_unpin(struct ttm_buffer_object *bo)
+{
+       dma_resv_assert_held(bo->base.resv);
+       WARN_ON_ONCE(!bo->pin_count);
+       --bo->pin_count;
+}
+
 int ttm_mem_evict_first(struct ttm_bo_device *bdev,
                        struct ttm_resource_manager *man,
                        const struct ttm_place *place,