Re: [PATCH 05/59] drm/ttm/amdgpu: consolidate ttm reserve paths

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Am 04.08.20 um 04:55 schrieb Dave Airlie:
From: Dave Airlie <airlied@xxxxxxxxxx>

Drop the WARN_ON and consolidate the two paths into one.

Use the consolidate slowpath in the execbuf utils code.

Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>

Reviewed-by: Christian König <christian.koenig@xxxxxxx>

---
  drivers/gpu/drm/amd/amdgpu/amdgpu_object.h |  2 +-
  drivers/gpu/drm/ttm/ttm_execbuf_util.c     | 12 +--
  include/drm/ttm/ttm_bo_driver.h            | 91 ++++------------------
  3 files changed, 20 insertions(+), 85 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index afa5189dba7d..e01e8903741e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -160,7 +160,7 @@ static inline int amdgpu_bo_reserve(struct amdgpu_bo *bo, bool no_intr)
  	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
  	int r;
- r = __ttm_bo_reserve(&bo->tbo, !no_intr, false, NULL);
+	r = ttm_bo_reserve(&bo->tbo, !no_intr, false, NULL);
  	if (unlikely(r != 0)) {
  		if (r != -ERESTARTSYS)
  			dev_err(adev->dev, "%p reserve failed\n", bo);
diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index 1797f04c0534..8a8f1a6a83a6 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -93,7 +93,7 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  	list_for_each_entry(entry, list, head) {
  		struct ttm_buffer_object *bo = entry->bo;
- ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
+		ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
  		if (ret == -EALREADY && dups) {
  			struct ttm_validate_buffer *safe = entry;
  			entry = list_prev_entry(entry, head);
@@ -119,13 +119,7 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  		ttm_eu_backoff_reservation_reverse(list, entry);
if (ret == -EDEADLK) {
-			if (intr) {
-				ret = dma_resv_lock_slow_interruptible(bo->base.resv,
-										 ticket);
-			} else {
-				dma_resv_lock_slow(bo->base.resv, ticket);
-				ret = 0;
-			}
+			ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
  		}
if (!ret && entry->num_shared)
@@ -133,8 +127,6 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  								entry->num_shared);
if (unlikely(ret != 0)) {
-			if (ret == -EINTR)
-				ret = -ERESTARTSYS;
  			if (ticket) {
  				ww_acquire_done(ticket);
  				ww_acquire_fini(ticket);
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 09211ecbf84f..c20fef4da1d3 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -588,29 +588,30 @@ int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible);
  void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
/**
- * __ttm_bo_reserve:
+ * ttm_bo_reserve:
   *
   * @bo: A pointer to a struct ttm_buffer_object.
   * @interruptible: Sleep interruptible if waiting.
   * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
   * @ticket: ticket used to acquire the ww_mutex.
   *
- * Will not remove reserved buffers from the lru lists.
- * Otherwise identical to ttm_bo_reserve.
+ * Locks a buffer object for validation. (Or prevents other processes from
+ * locking it for validation), while taking a number of measures to prevent
+ * deadlocks.
   *
   * Returns:
   * -EDEADLK: The reservation may cause a deadlock.
   * Release all buffer reservations, wait for @bo to become unreserved and
- * try again. (only if use_sequence == 1).
+ * try again.
   * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
   * a signal. Release all buffer reservations and return to user-space.
   * -EBUSY: The function needed to sleep, but @no_wait was true
   * -EALREADY: Bo already reserved using @ticket. This error code will only
   * be returned if @use_ticket is set to true.
   */
-static inline int __ttm_bo_reserve(struct ttm_buffer_object *bo,
-				   bool interruptible, bool no_wait,
-				   struct ww_acquire_ctx *ticket)
+static inline int ttm_bo_reserve(struct ttm_buffer_object *bo,
+				 bool interruptible, bool no_wait,
+				 struct ww_acquire_ctx *ticket)
  {
  	int ret = 0;
@@ -632,59 +633,6 @@ static inline int __ttm_bo_reserve(struct ttm_buffer_object *bo,
  	return ret;
  }
-/**
- * ttm_bo_reserve:
- *
- * @bo: A pointer to a struct ttm_buffer_object.
- * @interruptible: Sleep interruptible if waiting.
- * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
- * @ticket: ticket used to acquire the ww_mutex.
- *
- * Locks a buffer object for validation. (Or prevents other processes from
- * locking it for validation) and removes it from lru lists, while taking
- * a number of measures to prevent deadlocks.
- *
- * Deadlocks may occur when two processes try to reserve multiple buffers in
- * different order, either by will or as a result of a buffer being evicted
- * to make room for a buffer already reserved. (Buffers are reserved before
- * they are evicted). The following algorithm prevents such deadlocks from
- * occurring:
- * Processes attempting to reserve multiple buffers other than for eviction,
- * (typically execbuf), should first obtain a unique 32-bit
- * validation sequence number,
- * and call this function with @use_ticket == 1 and @ticket->stamp == the unique
- * sequence number. If upon call of this function, the buffer object is already
- * reserved, the validation sequence is checked against the validation
- * sequence of the process currently reserving the buffer,
- * and if the current validation sequence is greater than that of the process
- * holding the reservation, the function returns -EDEADLK. Otherwise it sleeps
- * waiting for the buffer to become unreserved, after which it retries
- * reserving.
- * The caller should, when receiving an -EDEADLK error
- * release all its buffer reservations, wait for @bo to become unreserved, and
- * then rerun the validation with the same validation sequence. This procedure
- * will always guarantee that the process with the lowest validation sequence
- * will eventually succeed, preventing both deadlocks and starvation.
- *
- * Returns:
- * -EDEADLK: The reservation may cause a deadlock.
- * Release all buffer reservations, wait for @bo to become unreserved and
- * try again. (only if use_sequence == 1).
- * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
- * a signal. Release all buffer reservations and return to user-space.
- * -EBUSY: The function needed to sleep, but @no_wait was true
- * -EALREADY: Bo already reserved using @ticket. This error code will only
- * be returned if @use_ticket is set to true.
- */
-static inline int ttm_bo_reserve(struct ttm_buffer_object *bo,
-				 bool interruptible, bool no_wait,
-				 struct ww_acquire_ctx *ticket)
-{
-	WARN_ON(!kref_read(&bo->kref));
-
-	return __ttm_bo_reserve(bo, interruptible, no_wait, ticket);
-}
-
  /**
   * ttm_bo_reserve_slowpath:
   * @bo: A pointer to a struct ttm_buffer_object.
@@ -699,20 +647,15 @@ static inline int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
  					  bool interruptible,
  					  struct ww_acquire_ctx *ticket)
  {
-	int ret = 0;
-
-	WARN_ON(!kref_read(&bo->kref));
-
-	if (interruptible)
-		ret = dma_resv_lock_slow_interruptible(bo->base.resv,
-								 ticket);
-	else
-		dma_resv_lock_slow(bo->base.resv, ticket);
-
-	if (ret == -EINTR)
-		ret = -ERESTARTSYS;
-
-	return ret;
+	if (interruptible) {
+		int ret = dma_resv_lock_slow_interruptible(bo->base.resv,
+							   ticket);
+		if (ret == -EINTR)
+			ret = -ERESTARTSYS;
+		return ret;
+	}
+	dma_resv_lock_slow(bo->base.resv, ticket);
+	return 0;
  }
/**

_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux