Bug 913953 - Part i: Remove unused ReduceWorkingSet and UnReduceWorkingSet functions; r=ehsan

ipc/chromium/src/base/process.h

@@ -65,20 +65,6 @@ class Process {
   // Returns true if the priority was changed, false otherwise.
   bool SetProcessBackgrounded(bool value);
 
-  // Reduces the working set of memory used by the process.
-  // The algorithm used by this function is intentionally vague.  Repeated calls
-  // to this function consider the process' previous required Working Set sizes
-  // to determine a reasonable reduction.  This helps give memory back to the OS
-  // in increments without over releasing memory.
-  // When the WorkingSet is reduced, it is permanent, until the caller calls
-  // UnReduceWorkingSet.
-  // Returns true if successful, false otherwise.
-  bool ReduceWorkingSet();
-
-  // Undoes the effects of prior calls to ReduceWorkingSet().
-  // Returns true if successful, false otherwise.
-  bool UnReduceWorkingSet();
-
   // Releases as much of the working set back to the OS as possible.
   // Returns true if successful, false otherwise.
   bool EmptyWorkingSet();

ipc/chromium/src/base/process_posix.cc

@@ -36,16 +36,6 @@ bool Process::SetProcessBackgrounded(bool value) {
   return true;
 }
 
-bool Process::ReduceWorkingSet() {
-  // http://code.google.com/p/chromium/issues/detail?id=8083
-  return false;
-}
-
-bool Process::UnReduceWorkingSet() {
-  // http://code.google.com/p/chromium/issues/detail?id=8083
-  return false;
-}
-
 bool Process::EmptyWorkingSet() {
   // http://code.google.com/p/chromium/issues/detail?id=8083
   return false;

ipc/chromium/src/base/process_win.cc

@@ -36,69 +36,6 @@ bool Process::SetProcessBackgrounded(bool value) {
   return (SetPriorityClass(process_, priority) != 0);
 }
 
-// According to MSDN, these are the default values which XP
-// uses to govern working set soft limits.
-// http://msdn.microsoft.com/en-us/library/ms686234.aspx
-static const int kWinDefaultMinSet = 50 * 4096;
-static const int kWinDefaultMaxSet = 345 * 4096;
-static const int kDampingFactor = 2;
-
-bool Process::ReduceWorkingSet() {
-  if (!process_)
-    return false;
-  // The idea here is that when we the process' working set has gone
-  // down, we want to release those pages to the OS quickly.  However,
-  // when it is not going down, we want to be careful not to release
-  // too much back to the OS, as it could cause additional paging.
-
-  // We use a damping function to lessen the working set over time.
-  // As the process grows/shrinks, this algorithm will lag with
-  // working set reduction.
-  //
-  // The intended algorithm is:
-  //   TargetWorkingSetSize = (LastWorkingSet/2 + CurrentWorkingSet) /2
-
-  scoped_ptr<ProcessMetrics> metrics(
-      ProcessMetrics::CreateProcessMetrics(process_));
-  WorkingSetKBytes working_set;
-  if (!metrics->GetWorkingSetKBytes(&working_set))
-    return false;
-
-
-  // We want to compute the amount of working set that the process
-  // needs to keep in memory.  Since other processes contain the
-  // pages which are shared, we don't need to reserve them in our
-  // process, the system already has them tagged.  Keep in mind, we
-  // don't get to control *which* pages get released, but if we
-  // assume reasonable distribution of pages, this should generally
-  // be the right value.
-  size_t current_working_set_size  = working_set.priv +
-                                     working_set.shareable;
-
-  size_t max_size = current_working_set_size;
-  if (last_working_set_size_)
-    max_size = (max_size + last_working_set_size_) / 2;  // Average.
-  max_size *= 1024;  // Convert to KBytes.
-  last_working_set_size_ = current_working_set_size / kDampingFactor;
-
-  BOOL rv = SetProcessWorkingSetSize(process_, kWinDefaultMinSet, max_size);
-  return rv == TRUE;
-}
-
-bool Process::UnReduceWorkingSet() {
-  if (!process_)
-    return false;
-
-  if (!last_working_set_size_)
-    return true;  // There was nothing to undo.
-
-  // We've had a reduced working set.  Make sure we have lots of
-  // headroom now that we're active again.
-  size_t limit = last_working_set_size_ * kDampingFactor * 2 * 1024;
-  BOOL rv = SetProcessWorkingSetSize(process_, kWinDefaultMinSet, limit);
-  return rv == TRUE;
-}
-
 bool Process::EmptyWorkingSet() {
   if (!process_)
     return false;

ipc/chromium/src/chrome/common/child_process_info.h

@@ -38,7 +38,6 @@ class ChildProcessInfo {
     return pid_;
   }
   void SetProcessBackgrounded() const { process_.SetProcessBackgrounded(true); }
-  void ReduceWorkingSet() const { process_.ReduceWorkingSet(); }
 
   // Returns an English name of the process type, should only be used for non
   // user-visible strings, or debugging pages like about:memory.