Add memory stats for linux page cycler. On linux, we collect

base/process_util.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file/namespace contains utility functions for enumerating, ending and
 // computing statistics of processes.
 
 #ifndef BASE_PROCESS_UTIL_H_
 #define BASE_PROCESS_UTIL_H_
 
@@ skipping 305 matching lines @@
 // methods.
 class ProcessMetrics {
  public:
   // Creates a ProcessMetrics for the specified process.
   // The caller owns the returned object.
   static ProcessMetrics* CreateProcessMetrics(ProcessHandle process);
 
   ~ProcessMetrics();
 
   // Returns the current space allocated for the pagefile, in bytes (these pages
-  // may or may not be in memory).
+  // may or may not be in memory).  On Linux, this returns the total virtual
+  // memory size.
   size_t GetPagefileUsage() const;
   // Returns the peak space allocated for the pagefile, in bytes.
   size_t GetPeakPagefileUsage() const;
-  // Returns the current working set size, in bytes.
+  // Returns the current working set size, in bytes.  On Linux, this returns
+  // the resident set size.
   size_t GetWorkingSetSize() const;
+  // Returns the peak working set size, in bytes.
+  size_t GetPeakWorkingSetSize() const;
   // Returns private usage, in bytes. Private bytes is the amount
   // of memory currently allocated to a process that cannot be shared.
   // Note: returns 0 on unsupported OSes: prior to XP SP2.
   size_t GetPrivateBytes() const;
   // Fills a CommittedKBytes with both resident and paged
   // memory usage as per definition of CommittedBytes.
   void GetCommittedKBytes(CommittedKBytes* usage) const;
   // Fills a WorkingSetKBytes containing resident private and shared memory
   // usage in bytes, as per definition of WorkingSetBytes.
   bool GetWorkingSetKBytes(WorkingSetKBytes* ws_usage) const;
@@ skipping 45 matching lines @@
 // overflow. Has no effect if the OS doesn't provide the necessary facility.
 void EnableTerminationOnHeapCorruption();
 
 // If supported on the platform, and the user has sufficent rights, increase
 // the current process's scheduling priority to a high priority.
 void RaiseProcessToHighPriority();
 
 }  // namespace base
 
 #endif  // BASE_PROCESS_UTIL_H_