commit a3e7ddc06efaf5391e0dbe2fa46c4e735fc98daa
author Chia-I Wu <olv@google.com> Thu Sep 20 11:42:46 2018 -0700
committer Chia-I Wu <olv@google.com> Thu Sep 20 16:06:37 2018 -0700
tree 841aadd8d9c93262614b09f14f54ace631178e04
parent ab19909a2a5ee41950e5685925346b805e6831ae

surfaceflinger: free SurfaceTracing memory

Allocate LayersTraceFileProto on the heap because Clear does not
free the memory.  Replace mTrace->Clear() by mTrace.reset().

This is temporary.  Eventually, we want to enable continuous tracing
and dump only the last N frames.  We will record LayersProto in a
circular buffer and create LayersTraceFileProto only to serialize
the buffer to a file.

Bug: 115434782
Test: winscope trace
Change-Id: I3a3e499ace08cd4b06c38be8ad2ad59bfcdba5d7

services/surfaceflinger/SurfaceTracing.cpp

diff --git a/services/surfaceflinger/SurfaceTracing.cpp b/services/surfaceflinger/SurfaceTracing.cpp
index 370b3b8..67dcd06 100644
--- a/services/surfaceflinger/SurfaceTracing.cpp
+++ b/services/surfaceflinger/SurfaceTracing.cpp
@@ -27,32 +27,36 @@
 namespace android {
 
 void SurfaceTracing::enable() {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
+
     if (mEnabled) {
         return;
     }
-    ATRACE_CALL();
     mEnabled = true;
-    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
 
-    mTrace.set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
-                            LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
+    mTrace = std::make_unique<LayersTraceFileProto>();
+    mTrace->set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
+                             LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
 }
 
 status_t SurfaceTracing::disable() {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
+
     if (!mEnabled) {
         return NO_ERROR;
     }
-    ATRACE_CALL();
-    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
     mEnabled = false;
     status_t err(writeProtoFileLocked());
     ALOGE_IF(err == PERMISSION_DENIED, "Could not save the proto file! Permission denied");
     ALOGE_IF(err == NOT_ENOUGH_DATA, "Could not save the proto file! There are missing fields");
-    mTrace.Clear();
+    mTrace.reset();
     return err;
 }
 
 bool SurfaceTracing::isEnabled() const {
+    std::lock_guard<std::mutex> protoGuard(mTraceMutex);
     return mEnabled;
 }
 
@@ -61,29 +65,29 @@
     if (!mEnabled) {
         return;
     }
-    LayersTraceProto* entry = mTrace.add_entry();
+    LayersTraceProto* entry = mTrace->add_entry();
     entry->set_elapsed_realtime_nanos(elapsedRealtimeNano());
     entry->set_where(where);
     entry->mutable_layers()->Swap(&layers);
 
     constexpr int maxBufferedEntryCount = 3600;
-    if (mTrace.entry_size() >= maxBufferedEntryCount) {
+    if (mTrace->entry_size() >= maxBufferedEntryCount) {
         // TODO: flush buffered entries without disabling tracing
         ALOGE("too many buffered frames; force disable tracing");
         mEnabled = false;
         writeProtoFileLocked();
-        mTrace.Clear();
+        mTrace.reset();
     }
 }
 
 status_t SurfaceTracing::writeProtoFileLocked() {
     ATRACE_CALL();
 
-    if (!mTrace.IsInitialized()) {
+    if (!mTrace->IsInitialized()) {
         return NOT_ENOUGH_DATA;
     }
     std::string output;
-    if (!mTrace.SerializeToString(&output)) {
+    if (!mTrace->SerializeToString(&output)) {
         return PERMISSION_DENIED;
     }
     if (!android::base::WriteStringToFile(output, mOutputFileName, true)) {
@@ -97,7 +101,7 @@
     std::lock_guard<std::mutex> protoGuard(mTraceMutex);
 
     result.appendFormat("Tracing state: %s\n", mEnabled ? "enabled" : "disabled");
-    result.appendFormat("  number of entries: %d\n", mTrace.entry_size());
+    result.appendFormat("  number of entries: %d\n", mTrace ? mTrace->entry_size() : 0);
 }
 
 } // namespace android