gpu: nvgpu: create sync_fence only if needed

Currently, we create sync_fence (from nvhost_sync_create_fence())
for every submit
But not all submits request for a sync_fence.

Also, nvhost_sync_create_fence() API takes about 1/3rd of the total
submit path.

Hence to optimize, we can allocate sync_fence
only when user explicitly asks for it using
(NVGPU_SUBMIT_GPFIFO_FLAGS_FENCE_GET &&
NVGPU_SUBMIT_GPFIFO_FLAGS_SYNC_FENCE)

Also, in CDE path from gk20a_prepare_compressible_read(),
we reuse existing fence stored in "state" and that can
result into not returning sync_fence_fd when user asked
for it
Hence, force allocation of sync_fence when job submission
comes from CDE path

Bug 200141116

Change-Id: Ia921701bf0e2432d6b8a5e8b7d91160e7f52db1e
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/812845
(cherry picked from commit 5fd47015eeed00352cc8473eff969a66c94fee98)
Reviewed-on: http://git-master/r/837662
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sachin Nikam <snikam@nvidia.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
index 54a288cd..ae19d36f 100644
--- a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
@@ -194,7 +194,8 @@ static const struct gk20a_fence_ops gk20a_syncpt_fence_ops = {
 };
 
 struct gk20a_fence *gk20a_fence_from_syncpt(struct platform_device *host1x_pdev,
-                                            u32 id, u32 value, bool wfi)
+                                            u32 id, u32 value, bool wfi,
+                                            bool need_sync_fence)
 {
         struct gk20a_fence *f;
         struct sync_fence *sync_fence = NULL;
@@ -205,10 +206,12 @@ struct gk20a_fence *gk20a_fence_from_syncpt(struct platform_device *host1x_pdev,
                 .thresh = value
         };
 
-        sync_fence = nvhost_sync_create_fence(host1x_pdev, &pt, 1,
-                                              "fence");
-        if (IS_ERR(sync_fence))
-                return NULL;
+        if (need_sync_fence) {
+                sync_fence = nvhost_sync_create_fence(host1x_pdev, &pt, 1,
+                                                      "fence");
+                if (IS_ERR(sync_fence))
+                        return NULL;
+        }
 #endif
 
         f = alloc_fence(&gk20a_syncpt_fence_ops, sync_fence, wfi);