A deeper heap profile dumper in third_party/tcmalloc/chromium.

third_party/tcmalloc/chromium/src/heap-profiler.cc

Index: third_party/tcmalloc/chromium/src/heap-profiler.cc
diff --git a/third_party/tcmalloc/chromium/src/heap-profiler.cc b/third_party/tcmalloc/chromium/src/heap-profiler.cc
index 25bed9a4e087cf6814b57dc5b0a1fda071202d23..5f3a8e7f18518f7d948805feb42bf183b838b61f 100644
--- a/third_party/tcmalloc/chromium/src/heap-profiler.cc
+++ b/third_party/tcmalloc/chromium/src/heap-profiler.cc
@@ -68,6 +68,7 @@
 #include "base/spinlock.h"
 #include "base/low_level_alloc.h"
 #include "base/sysinfo.h"      // for GetUniquePathFromEnv()
+#include "deep-heap-profile.h"
 #include "heap-profile-table.h"
 #include "memory_region_map.h"
 
@@ -121,6 +122,9 @@ DEFINE_bool(only_mmap_profile,
             EnvToBool("HEAP_PROFILE_ONLY_MMAP", false),
             "If heap-profiling is on, only profile mmap, mremap, and sbrk; "
             "do not profile malloc/new/etc");
+DEFINE_bool(deep_heap_profile,
+            EnvToBool("DEEP_HEAP_PROFILE", false),
+            "If heap-profiling is on, profile deeper (only on Linux)");
 
 
 //----------------------------------------------------------------------
@@ -175,6 +179,7 @@ static int64 high_water_mark = 0;     // In-use-bytes at last high-water dump
 static int64 last_dump_time = 0;      // The time of the last dump
 
 static HeapProfileTable* heap_profile = NULL;  // the heap profile table
+static DeepHeapProfile* deep_profile = NULL;  // deep memory profiler
 
 //----------------------------------------------------------------------
 // Profile generation
@@ -193,7 +198,11 @@ static char* DoGetHeapProfileLocked(char* buf, int buflen) {
     if (FLAGS_mmap_profile) {
       heap_profile->RefreshMMapData();
     }
-    bytes_written = heap_profile->FillOrderedProfile(buf, buflen - 1);
+    if (FLAGS_deep_heap_profile) {
+      bytes_written = deep_profile->FillOrderedProfile(buf, buflen - 1);
+    } else {
+      bytes_written = heap_profile->FillOrderedProfile(buf, buflen - 1);

[Alexander Potapenko, 2011/12/20 13:57:23]

Does deep_profile replace heap_profile everywhere if FLAGS_deep_heap_profile==1?
If so, you may want to initialize heap_profile with NULL and check that it's
still NULL in HeapProfilerStop().

Another option is to inherit DeepHeapProfile from HeapProfileTable.

[Dai Mikurube (NOT FULLTIME), 2011/12/21 09:13:49]

deep_profile does get information from heap_profile when dumping is requested,
merge some information from OS, and then dump the merged information. 
heap_profile works the same way.

We chose this design in order
1) to reduce changes in the original code, and
2) to avoid overhead when FLAGS_deep_heap_profile==0.

Additional overhead is unacceptable, for example, in RecordAlloc and RecordFree
since they're called every malloc/free.  Additional if-statements or virtual
functions add overheads.

Inheriting DeepHeapProfile from HeapProfileTable might be a good idea if only
FillOrderedProfile is a virtual function.  But I guess it doesn't have so large
benefit at this time...

+    }
     if (FLAGS_mmap_profile) {
       heap_profile->ClearMMapData();
     }
@@ -457,6 +466,13 @@ extern "C" void HeapProfilerStart(const char* prefix) {
   high_water_mark = 0;
   last_dump_time = 0;
 
+  if (FLAGS_deep_heap_profile) {
+    // Initialize deep memory profiler
+    RAW_VLOG(0, "[%d] Starting a deep memory profiler", getpid());
+    deep_profile = new(ProfilerMalloc(sizeof(DeepHeapProfile)))

[Alexander Potapenko, 2011/12/20 13:57:23]

I wouldn't have aligned the placement new arguments this way, but looks like
nobody cares in this file, so it's better to be consistent.

[Dai Mikurube (NOT FULLTIME), 2011/12/21 09:13:49]

It's the first time also for me to see this way.  But I used the same way to be
consistent, as you say. :)

+        DeepHeapProfile(heap_profile, prefix);
+  }
+
   // We do not reset dump_count so if the user does a sequence of
   // HeapProfilerStart/HeapProfileStop, we will get a continuous
   // sequence of profiles.
@@ -498,6 +514,13 @@ extern "C" void HeapProfilerStop() {
     RAW_CHECK(MallocHook::RemoveMunmapHook(&MunmapHook), "");
   }
 
+  if (FLAGS_deep_heap_profile) {
+    // free deep memory profiler
+    deep_profile->~DeepHeapProfile();
+    ProfilerFree(deep_profile);
+    deep_profile = NULL;
+  }
+
   // free profile
   heap_profile->~HeapProfileTable();
   ProfilerFree(heap_profile);