Re: [PATCH 01/11] drm/ttm: add ttm_bo_pin()/ttm_bo_unpin() v2

On Tue, Sep 22, 2020 at 09:31:58PM +0800, Christian König wrote:

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

Series look good for me as well.

Reviewed-by: Huang Rui ray.huang@amd.com

Only one comment:

We can modify the TOPDOWN offset as 21 since the NO_EVICT is removed.

#define TTM_PL_FLAG_UNCACHED (1 << 17) #define TTM_PL_FLAG_WC (1 << 18) #define TTM_PL_FLAG_CONTIGUOUS (1 << 19) -#define TTM_PL_FLAG_NO_EVICT (1 << 21) #define TTM_PL_FLAG_TOPDOWN (1 << 22)

Thanks, Ray

---

drivers/gpu/drm/ttm/ttm_bo.c | 9 ++++++--- drivers/gpu/drm/ttm/ttm_bo_util.c | 2 +- include/drm/ttm/ttm_bo_api.h | 26 ++++++++++++++++++++++++++ 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 70b3bee27850..b82b49d43942 100644 --- 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 fb2a25f8408f..1968df9743fc 100644 --- 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 0f7cd21d6d74..33aca60870e2 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -157,6 +157,7 @@ struct ttm_buffer_object {

struct dma_fence *moving; unsigned priority;

• unsigned pin_count;

  /**

  • Special members that are protected by the reserve lock

@@ -606,6 +607,31 @@ 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, -- 2.17.1