Issue 172109: Enable scavenging in RenderThread::IdleHandler....

third_party/tcmalloc/google/malloc_extension.h

+// 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
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// ---
+// Author: Sanjay Ghemawat <opensource@google.com>
+//
+// Extra extensions exported by some malloc implementations.  These
+// extensions are accessed through a virtual base class so an
+// application can link against a malloc that does not implement these
+// extensions, and it will get default versions that do nothing.
+//
+// NOTE FOR C USERS: If you wish to use this functionality from within
+// a C program, see malloc_extension_c.h.
+
+#ifndef BASE_MALLOC_EXTENSION_H_
+#define BASE_MALLOC_EXTENSION_H_
+
+#include <stddef.h>
+#include <string>
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef PERFTOOLS_DLL_DECL
+# ifdef _WIN32
+#   define PERFTOOLS_DLL_DECL  __declspec(dllimport)
+# else
+#   define PERFTOOLS_DLL_DECL
+# endif
+#endif
+
+static const int kMallocHistogramSize = 64;
+
+// One day, we could support other types of writers (perhaps for C?)
+typedef std::string MallocExtensionWriter;
+
+// The default implementations of the following routines do nothing.
+// All implementations should be thread-safe; the current one
+// (TCMallocImplementation) is.
+class PERFTOOLS_DLL_DECL MallocExtension {
+ public:
+  virtual ~MallocExtension();
+
+  // Call this very early in the program execution -- say, in a global
+  // constructor -- to set up parameters and state needed by all
+  // instrumented malloc implemenatations.  One example: this routine
+  // sets environemnt variables to tell STL to use libc's malloc()
+  // instead of doing its own memory management.  This is safe to call
+  // multiple times, as long as each time is before threads start up.
+  static void Initialize();
+
+  // See "verify_memory.h" to see what these routines do
+  virtual bool VerifyAllMemory();
+  virtual bool VerifyNewMemory(void* p);
+  virtual bool VerifyArrayNewMemory(void* p);
+  virtual bool VerifyMallocMemory(void* p);
+  virtual bool MallocMemoryStats(int* blocks, size_t* total,
+                                 int histogram[kMallocHistogramSize]);
+
+  // Get a human readable description of the current state of the malloc
+  // data structures.  The state is stored as a null-terminated string
+  // in a prefix of "buffer[0,buffer_length-1]".
+  // REQUIRES: buffer_length > 0.
+  virtual void GetStats(char* buffer, int buffer_length);
+
+  // Outputs to "writer" a sample of live objects and the stack traces
+  // that allocated these objects.  The format of the returned output
+  // is equivalent to the output of the heap profiler and can
+  // therefore be passed to "pprof".
+  virtual void GetHeapSample(MallocExtensionWriter* writer);
+
+  // Outputs to "writer" the stack traces that caused growth in the
+  // address space size.  The format of the returned output is
+  // equivalent to the output of the heap profiler and can therefore
+  // be passed to "pprof".
+  virtual void GetHeapGrowthStacks(MallocExtensionWriter* writer);
+
+  // -------------------------------------------------------------------
+  // Control operations for getting and setting malloc implementation
+  // specific parameters.  Some currently useful properties:
+  //
+  // generic
+  // -------
+  // "generic.current_allocated_bytes"
+  //      Number of bytes currently allocated by application
+  //      This property is not writable.
+  //
+  // "generic.heap_size"
+  //      Number of bytes in the heap ==
+  //            current_allocated_bytes +
+  //            fragmentation +
+  //            freed memory regions
+  //      This property is not writable.
+  //
+  // tcmalloc
+  // --------
+  // "tcmalloc.max_total_thread_cache_bytes"
+  //      Upper limit on total number of bytes stored across all
+  //      per-thread caches.  Default: 16MB.
+  //
+  // "tcmalloc.current_total_thread_cache_bytes"
+  //      Number of bytes used across all thread caches.
+  //      This property is not writable.
+  //
+  // "tcmalloc.slack_bytes"
+  //      Number of bytes allocated from system, but not currently
+  //      in use by malloced objects.  I.e., bytes available for
+  //      allocation without needing more bytes from system.
+  //      This property is not writable.
+  //
+  // TODO: Add more properties as necessary
+  // -------------------------------------------------------------------
+
+  // Get the named "property"'s value.  Returns true if the property
+  // is known.  Returns false if the property is not a valid property
+  // name for the current malloc implementation.
+  // REQUIRES: property != NULL; value != NULL
+  virtual bool GetNumericProperty(const char* property, size_t* value);
+
+  // Set the named "property"'s value.  Returns true if the property
+  // is known and writable.  Returns false if the property is not a
+  // valid property name for the current malloc implementation, or
+  // is not writable.
+  // REQUIRES: property != NULL
+  virtual bool SetNumericProperty(const char* property, size_t value);
+
+  // Mark the current thread as "idle".  This routine may optionally
+  // be called by threads as a hint to the malloc implementation that
+  // any thread-specific resources should be released.  Note: this may
+  // be an expensive routine, so it should not be called too often.
+  //
+  // Also, if the code that calls this routine will go to sleep for
+  // a while, it should take care to not allocate anything between
+  // the call to this routine and the beginning of the sleep.
+  //
+  // Most malloc implementations ignore this routine.
+  virtual void MarkThreadIdle();
+
+  // Scavenge at least some resources and free them back to OS.
+  // This method doesn't promise to do anything useful (it might be
+  // implemented as noop), but it's a good idea to invoke it when
+  // application is idle.
+  virtual void Scavenge();
+
+  // Try to free memory back to the operating system for reuse.  Only
+  // use this extension if the application has recently freed a lot of
+  // memory, and does not anticipate using it again for a long time --
+  // to get this memory back may require faulting pages back in by the
+  // OS, and that may be slow.  (Currently only implemented in
+  // tcmalloc.)
+  virtual void ReleaseFreeMemory();
+
+  // Sets the rate at which we release unused memory to the system.
+  // Zero means we never release memory back to the system.  Increase
+  // this flag to return memory faster; decrease it to return memory
+  // slower.  Reasonable rates are in the range [0,10].  (Currently
+  // only implemented in tcmalloc).
+  virtual void SetMemoryReleaseRate(double rate);
+
+  // Gets the release rate.  Returns a value < 0 if unknown.
+  virtual double GetMemoryReleaseRate();
+
+  // Returns the estimated number of bytes that will be allocated for
+  // a request of "size" bytes.  This is an estimate: an allocation of
+  // SIZE bytes may reserve more bytes, but will never reserve less.
+  // (Currently only implemented in tcmalloc, other implementations
+  // always return SIZE.)
+  virtual size_t GetEstimatedAllocatedSize(size_t size);
+
+  // Returns the actual number of bytes reserved by tcmalloc for the
+  // pointer p.  This number may be equal to or greater than
+  // the number of bytes requested when p was allocated.
+  // p must have been allocated by this malloc implementation,
+  // must not be an interior pointer -- that is, must be exactly
+  // the pointer returned to by malloc() et al., not some offset
+  // from that -- and should not have been freed yet.  p may be NULL.
+  // (Currently only implemented in tcmalloc; other implementations
+  // will return 0.)
+  virtual size_t GetAllocatedSize(void* p);
+
+  // The current malloc implementation.  Always non-NULL.
+  static MallocExtension* instance();
+
+  // Change the malloc implementation.  Typically called by the
+  // malloc implementation during initialization.
+  static void Register(MallocExtension* implementation);
+
+ protected:
+  // Get a list of stack traces of sampled allocation points.  Returns
+  // a pointer to a "new[]-ed" result array, and stores the sample
+  // period in "sample_period".
+  //
+  // The state is stored as a sequence of adjacent entries
+  // in the returned array.  Each entry has the following form:
+  //    uintptr_t count;        // Number of objects with following trace
+  //    uintptr_t size;         // Total size of objects with following trace
+  //    uintptr_t depth;        // Number of PC values in stack trace
+  //    void*     stack[depth]; // PC values that form the stack trace
+  //
+  // The list of entries is terminated by a "count" of 0.
+  //
+  // It is the responsibility of the caller to "delete[]" the returned array.
+  //
+  // May return NULL to indicate no results.
+  //
+  // This is an internal extension.  Callers should use the more
+  // convenient "GetHeapSample(string*)" method defined above.
+  virtual void** ReadStackTraces(int* sample_period);
+
+  // Like ReadStackTraces(), but returns stack traces that caused growth
+  // in the address space size.
+  virtual void** ReadHeapGrowthStackTraces();
+};
+
+#endif  // BASE_MALLOC_EXTENSION_H_