Remove all MemoryModel-related code, since we're unlikely to use it again. Also changes some sample code to use a random generic name ("PruningAlgorithm") instead of MemoryModel in hopes that no one will be confused.

This does not remove IdleTimer, even though it now has no users.  I do plan to remove it, but I want to do that in a separate commit so it's easy to reference and revert if at some later point we want this functionality.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/242079

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27652 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 3 insertions, 107 deletions

diff --git a/base/field_trial.h b/base/field_trial.h
index 82bf3b36..0779981 100644
--- a/base/field_trial.h
+++ b/base/field_trial.h
@@ -22,7 +22,7 @@
 
 //------------------------------------------------------------------------------
 // Example:  Suppose we have an experiment involving memory, such as determining
-// the impact of memory model command line flags actual memory use.
+// the impact of some pruning algorithm.
 // We assume that we already have a histogram of memory usage, such as:
 
 //   HISTOGRAM_COUNTS("Memory.RendererTotal", count);
@@ -38,9 +38,9 @@
 // int group2 = trial->AppendGroup("_low_mem", 20);   // 2% in _low_mem group.
 // // Take action depending of which group we randomly land in.
 // if (trial->group() == group1)
-//   SetMemoryModel(HIGH);  // Sample setting of browser state.
+//   SetPruningAlgorithm(kType1);  // Sample setting of browser state.
 // else if (trial->group() == group2)
-//   SetMemoryModel(LOW);  // Sample alternate setting.
+//   SetPruningAlgorithm(kType2);  // Sample alternate setting.
 
 // We then modify any histograms we wish to correlate with our experiment to
 // have slighly different names, depending on what group the trial instance
diff --git a/base/process.h b/base/process.h
index 459ad58..fa076b9 100644
--- a/base/process.h
+++ b/base/process.h
@@ -66,24 +66,6 @@ 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();
-
  private:
   ProcessHandle process_;
   size_t last_working_set_size_;
diff --git a/base/process_posix.cc b/base/process_posix.cc
index c9a7dfc..f0e019a 100644
--- a/base/process_posix.cc
+++ b/base/process_posix.cc
@@ -36,21 +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;
-}
-
 ProcessId Process::pid() const {
   if (process_ == 0)
     return 0;
diff --git a/base/process_win.cc b/base/process_win.cc
index 263e577..469e7cd 100644
--- a/base/process_win.cc
+++ b/base/process_win.cc
@@ -38,77 +38,6 @@ 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;
-
-  BOOL rv = SetProcessWorkingSetSize(process_, -1, -1);
-  return rv == TRUE;
-}
-
 ProcessId Process::pid() const {
   if (process_ == 0)
     return 0;