commit 76892784ac7c3dde9c7c14d4e88d17960a445740
author Roman Stratiienko <r.stratiienko@gmail.com> Mon Jan 16 17:15:53 2023 +0200
committer Roman Stratiienko <r.stratiienko@gmail.com> Mon Jan 16 20:13:58 2023 +0200
tree 02c8eb5f5c25f5a7f436f2c1455c34953220591f
parent 2bf68c374976d0a7a0e71c1843cbeae2a3210b74

drm_hwcomposer: Introduce SharedFd, use standard c++ RAII for UniqueFd

We use too much dup() system calls for present fence propagating.
Also when propagating acquire fence we use additional logic for
skipping such propagation for the validate/test cycle.

Both issues can be solved by introducing SharedFd, which will track
reference count of fd object.

After that the UniqueFd is used very rarely and can be simplified by
wrapping it into std::unique_ptr without caring too much of adding
an extra malloc/free operation.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>

drm/DrmAtomicStateManager.cpp

diff --git a/drm/DrmAtomicStateManager.cpp b/drm/DrmAtomicStateManager.cpp
index b5e4629..58a5523 100644
--- a/drm/DrmAtomicStateManager.cpp
+++ b/drm/DrmAtomicStateManager.cpp
@@ -141,7 +141,7 @@
   uint32_t flags = DRM_MODE_ATOMIC_ALLOW_MODESET;
 
   if (args.test_only) {
-    return drmModeAtomicCommit(drm->GetFd(), pset.get(),
+    return drmModeAtomicCommit(*drm->GetFd(), pset.get(),
                                flags | DRM_MODE_ATOMIC_TEST_ONLY, drm);
   }
 
@@ -150,10 +150,10 @@
     ATRACE_NAME("WaitPriorFramePresented");
 
     constexpr int kTimeoutMs = 500;
-    const int err = sync_wait(last_present_fence_.Get(), kTimeoutMs);
+    const int err = sync_wait(*last_present_fence_, kTimeoutMs);
     if (err != 0) {
-      ALOGE("sync_wait(fd=%i) returned: %i (errno: %i)",
-            last_present_fence_.Get(), err, errno);
+      ALOGE("sync_wait(fd=%i) returned: %i (errno: %i)", *last_present_fence_,
+            err, errno);
     }
 
     CleanupPriorFrameResources();
@@ -163,17 +163,19 @@
     flags |= DRM_MODE_ATOMIC_NONBLOCK;
   }
 
-  auto err = drmModeAtomicCommit(drm->GetFd(), pset.get(), flags, drm);
+  auto err = drmModeAtomicCommit(*drm->GetFd(), pset.get(), flags, drm);
 
   if (err != 0) {
     ALOGE("Failed to commit pset ret=%d\n", err);
     return err;
   }
 
+  args.out_fence = MakeSharedFd(out_fence);
+
   if (nonblock) {
     {
       const std::unique_lock lock(mutex_);
-      last_present_fence_ = UniqueFd::Dup(out_fence);
+      last_present_fence_ = args.out_fence;
       staged_frame_state_ = std::move(new_frame_state);
       frames_staged_++;
     }
@@ -182,8 +184,6 @@
     active_frame_state_ = std::move(new_frame_state);
   }
 
-  args.out_fence = UniqueFd(out_fence);
-
   return 0;
 }
 
@@ -193,7 +193,7 @@
   auto &main_mutex = pipe_->device->GetResMan().GetMainLock();
 
   for (;;) {
-    UniqueFd present_fence;
+    SharedFd present_fence;
 
     {
       std::unique_lock lk(mutex_);
@@ -207,7 +207,7 @@
 
       tracking_at_the_moment = frames_staged_;
 
-      present_fence = UniqueFd::Dup(last_present_fence_.Get());
+      present_fence = last_present_fence_;
       if (!present_fence)
         continue;
     }
@@ -216,10 +216,10 @@
       // NOLINTNEXTLINE(misc-const-correctness)
       ATRACE_NAME("AsyncWaitForBuffersSwap");
       constexpr int kTimeoutMs = 500;
-      auto err = sync_wait(present_fence.Get(), kTimeoutMs);
+      auto err = sync_wait(*present_fence, kTimeoutMs);
       if (err != 0) {
-        ALOGE("sync_wait(fd=%i) returned: %i (errno: %i)", present_fence.Get(),
-              err, errno);
+        ALOGE("sync_wait(fd=%i) returned: %i (errno: %i)", *present_fence, err,
+              errno);
       }
     }
 
@@ -272,7 +272,7 @@
 }  // namespace android
 
 auto DrmAtomicStateManager::ActivateDisplayUsingDPMS() -> int {
-  return drmModeConnectorSetProperty(pipe_->device->GetFd(),
+  return drmModeConnectorSetProperty(*pipe_->device->GetFd(),
                                      pipe_->connector->Get()->GetId(),
                                      pipe_->connector->Get()
                                          ->GetDpmsProperty()