Add support for dump allocations created in a certain time window

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

 // Copyright (c) 2005, Google Inc.
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 // 
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 184 matching lines @@
 // exit due to out-of-memory.  This buffer is allocated in
 // HeapProfilerStart.  Access to this must be protected by heap_lock.
 static char* global_profiler_buffer = NULL;
 
 
 //----------------------------------------------------------------------
 // Profiling control/state data
 //----------------------------------------------------------------------
 
 // Access to all of these is protected by heap_lock.
 static bool  is_on = false;           // If are on as a subsytem.

[jar (doing other things), 2012/06/11 08:53:14]

nit: I couldn't make sense of the variable name, or the comment.

If this were to comply with Chromimum coding, then globals should have g_ as a
prefix.  I'm not sure if this is Chromium only code, or code based on some other
google distribution.

For this variable, it would be helpful to say something like
heap_profiler_active (unless this is google code... and we need to avoid
forking).

The current name has a pronoun, which is meaningless in a global context (though
it might mean something in a class), and especially confusing when I couldn't
even guess that this related to a global static :-/.  

[jochen (gone - plz use gerrit), 2012/06/11 13:13:47]

I agree that the variable naming is not optimal, but to keep the diff to
upstream as small as possible, I think it's better not to change it

 static bool  dumping = false;         // Dumping status to prevent recursion
 static char* filename_prefix = NULL;  // Prefix used for profile file names
                                       // (NULL if no need for dumping yet)
 static int   dump_count = 0;          // How many dumps so far
 static int64 last_dump_alloc = 0;     // alloc_size when did we last dump
 static int64 last_dump_free = 0;      // free_size when did we last dump
 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
@@ skipping 378 matching lines @@
   is_on = false;
 }
 
 extern "C" void HeapProfilerDump(const char* reason) {
   SpinLockHolder l(&heap_lock);
   if (is_on && !dumping) {
     DumpProfileLocked(reason);
   }
 }
 
+extern "C" void HeapProfilerMarkBaseline() {
+  SpinLockHolder l(&heap_lock);
+
+  if (!is_on) return;
+
+  heap_profile->MarkCurrentAllocations(HeapProfileTable::MARK_ONE);
+}
+
+extern "C" void HeapProfilerMarkInteresting() {
+  SpinLockHolder l(&heap_lock);
+
+  if (!is_on) return;
+
+  heap_profile->MarkUnmarkedAllocations(HeapProfileTable::MARK_TWO);
+}
+
+extern "C" void HeapProfilerDumpAliveObjects(const char* filename) {
+  SpinLockHolder l(&heap_lock);
+
+  if (!is_on) return;
+
+  heap_profile->DumpMarkedObjects(HeapProfileTable::MARK_TWO, filename);
+}
+
 //----------------------------------------------------------------------
 // Initialization/finalization code
 //----------------------------------------------------------------------
 
 // Initialization code
 static void HeapProfilerInit() {
   // Everything after this point is for setting up the profiler based on envvar
   char fname[PATH_MAX];
   if (!GetUniquePathFromEnv("HEAPPROFILE", fname)) {
     return;
@@ skipping 14 matching lines @@
 
 // class used for finalization -- dumps the heap-profile at program exit
 struct HeapProfileEndWriter {
   ~HeapProfileEndWriter() { HeapProfilerDump("Exiting"); }
 };
 
 // We want to make sure tcmalloc is up and running before starting the profiler
 static const TCMallocGuard tcmalloc_initializer;
 REGISTER_MODULE_INITIALIZER(heapprofiler, HeapProfilerInit());
 static HeapProfileEndWriter heap_profile_end_writer;