drm/i915: Prepare object synchronisation for asynchronicity

We are about to specialize object synchronisation to enable nonblocking
execbuf submission. First we make a copy of the current object
synchronisation for execbuffer. The general i915_gem_object_sync() will
be removed following the removal of CS flips in the near future.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: John Harrison <john.c.harrison@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-16-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 37978d3..1e2dda8 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3221,8 +3221,6 @@ i915_gem_obj_finish_shmem_access(struct drm_i915_gem_object *obj)
 }
 
 int __must_check i915_mutex_lock_interruptible(struct drm_device *dev);
-int i915_gem_object_sync(struct drm_i915_gem_object *obj,
-                        struct drm_i915_gem_request *to);
 void i915_vma_move_to_active(struct i915_vma *vma,
                             struct drm_i915_gem_request *req,
                             unsigned int flags);

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 89a5f8d..4b5364d 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2818,97 +2818,6 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
        return ret;
 }
 
-static int
-__i915_gem_object_sync(struct drm_i915_gem_request *to,
-                      struct drm_i915_gem_request *from)
-{
-       int ret;
-
-       if (to->engine == from->engine)
-               return 0;
-
-       if (!i915.semaphores) {
-               ret = i915_wait_request(from,
-                                       from->i915->mm.interruptible |
-                                       I915_WAIT_LOCKED,
-                                       NULL,
-                                       NO_WAITBOOST);
-               if (ret)
-                       return ret;
-       } else {
-               int idx = intel_engine_sync_index(from->engine, to->engine);
-               if (from->fence.seqno <= from->engine->semaphore.sync_seqno[idx])
-                       return 0;
-
-               trace_i915_gem_ring_sync_to(to, from);
-               ret = to->engine->semaphore.sync_to(to, from);
-               if (ret)
-                       return ret;
-
-               from->engine->semaphore.sync_seqno[idx] = from->fence.seqno;
-       }
-
-       return 0;
-}
-
-/**
- * i915_gem_object_sync - sync an object to a ring.
- *
- * @obj: object which may be in use on another ring.
- * @to: request we are wishing to use
- *
- * This code is meant to abstract object synchronization with the GPU.
- * Conceptually we serialise writes between engines inside the GPU.
- * We only allow one engine to write into a buffer at any time, but
- * multiple readers. To ensure each has a coherent view of memory, we must:
- *
- * - If there is an outstanding write request to the object, the new
- *   request must wait for it to complete (either CPU or in hw, requests
- *   on the same ring will be naturally ordered).
- *
- * - If we are a write request (pending_write_domain is set), the new
- *   request must wait for outstanding read requests to complete.
- *
- * Returns 0 if successful, else propagates up the lower layer error.
- */
-int
-i915_gem_object_sync(struct drm_i915_gem_object *obj,
-                    struct drm_i915_gem_request *to)
-{
-       struct i915_gem_active *active;
-       unsigned long active_mask;
-       int idx;
-
-       lockdep_assert_held(&obj->base.dev->struct_mutex);
-
-       active_mask = i915_gem_object_get_active(obj);
-       if (!active_mask)
-               return 0;
-
-       if (obj->base.pending_write_domain) {
-               active = obj->last_read;
-       } else {
-               active_mask = 1;
-               active = &obj->last_write;
-       }
-
-       for_each_active(active_mask, idx) {
-               struct drm_i915_gem_request *request;
-               int ret;
-
-               request = i915_gem_active_peek(&active[idx],
-                                              &obj->base.dev->struct_mutex);
-               if (!request)
-                       continue;
-
-               ret = __i915_gem_object_sync(to, request);
-               if (ret)
-                       return ret;
-       }
-
-       return 0;
-}
-
 static void __i915_vma_iounmap(struct i915_vma *vma)
 {
        GEM_BUG_ON(i915_vma_is_pinned(vma));

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 9432d4c..ccaf15b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1133,7 +1133,8 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req,
                struct drm_i915_gem_object *obj = vma->obj;
 
                if (obj->flags & other_rings) {
-                       ret = i915_gem_object_sync(obj, req);
+                       ret = i915_gem_request_await_object
+                               (req, obj, obj->base.pending_write_domain);
                        if (ret)
                                return ret;
                }

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index a149310..017cadf 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -460,6 +460,93 @@ err:
        return ERR_PTR(ret);
 }
 
+static int
+i915_gem_request_await_request(struct drm_i915_gem_request *to,
+                              struct drm_i915_gem_request *from)
+{
+       int idx, ret;
+
+       GEM_BUG_ON(to == from);
+
+       if (to->engine == from->engine)
+               return 0;
+
+       idx = intel_engine_sync_index(from->engine, to->engine);
+       if (from->fence.seqno <= from->engine->semaphore.sync_seqno[idx])
+               return 0;
+
+       trace_i915_gem_ring_sync_to(to, from);
+       if (!i915.semaphores) {
+               ret = i915_wait_request(from,
+                                       I915_WAIT_INTERRUPTIBLE |
+                                       I915_WAIT_LOCKED,
+                                       NULL, NO_WAITBOOST);
+               if (ret)
+                       return ret;
+       } else {
+               ret = to->engine->semaphore.sync_to(to, from);
+               if (ret)
+                       return ret;
+       }
+
+       from->engine->semaphore.sync_seqno[idx] = from->fence.seqno;
+       return 0;
+}
+
+/**
+ * i915_gem_request_await_object - set this request to (async) wait upon a bo
+ *
+ * @to: request we are wishing to use
+ * @obj: object which may be in use on another ring.
+ *
+ * This code is meant to abstract object synchronization with the GPU.
+ * Conceptually we serialise writes between engines inside the GPU.
+ * We only allow one engine to write into a buffer at any time, but
+ * multiple readers. To ensure each has a coherent view of memory, we must:
+ *
+ * - If there is an outstanding write request to the object, the new
+ *   request must wait for it to complete (either CPU or in hw, requests
+ *   on the same ring will be naturally ordered).
+ *
+ * - If we are a write request (pending_write_domain is set), the new
+ *   request must wait for outstanding read requests to complete.
+ *
+ * Returns 0 if successful, else propagates up the lower layer error.
+ */
+int
+i915_gem_request_await_object(struct drm_i915_gem_request *to,
+                             struct drm_i915_gem_object *obj,
+                             bool write)
+{
+       struct i915_gem_active *active;
+       unsigned long active_mask;
+       int idx;
+
+       if (write) {
+               active_mask = i915_gem_object_get_active(obj);
+               active = obj->last_read;
+       } else {
+               active_mask = 1;
+               active = &obj->last_write;
+       }
+
+       for_each_active(active_mask, idx) {
+               struct drm_i915_gem_request *request;
+               int ret;
+
+               request = i915_gem_active_peek(&active[idx],
+                                              &obj->base.dev->struct_mutex);
+               if (!request)
+                       continue;
+
+               ret = i915_gem_request_await_request(to, request);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
 static void i915_gem_mark_busy(const struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;

diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index e141b1c..883df3b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -209,6 +209,11 @@ static inline void i915_gem_request_assign(struct drm_i915_gem_request **pdst,
        *pdst = src;
 }
 
+int
+i915_gem_request_await_object(struct drm_i915_gem_request *to,
+                             struct drm_i915_gem_object *obj,
+                             bool write);
+
 void __i915_add_request(struct drm_i915_gem_request *req, bool flush_caches);
 #define i915_add_request(req) \
        __i915_add_request(req, true)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b92042f..69b80d0 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12273,7 +12273,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
                        goto cleanup_unpin;
                }
 
-               ret = i915_gem_object_sync(obj, request);
+               ret = i915_gem_request_await_object(request, obj, false);
                if (ret)
                        goto cleanup_request;