Port parts of base/process_util to Linux.

base/process.cc

Index: base/process.cc
===================================================================
--- base/process.cc	(revision 3009)
+++ base/process.cc	(working copy)
@@ -1,110 +0,0 @@
-// Copyright (c) 2006-2008 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.
-
-#include "base/process.h"
-#include "base/logging.h"
-#include "base/process_util.h"
-#include "base/scoped_ptr.h"
-
-bool Process::IsProcessBackgrounded() {
-  DCHECK(process_);
-  DWORD priority = GetPriorityClass(process_);
-  if (priority == 0)
-    return false;  // Failure case.
-  return priority == BELOW_NORMAL_PRIORITY_CLASS;
-}
-
-bool Process::SetProcessBackgrounded(bool value) {
-  DCHECK(process_);
-  DWORD priority = value ? BELOW_NORMAL_PRIORITY_CLASS : NORMAL_PRIORITY_CLASS;
-  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<process_util::ProcessMetrics> metrics(
-    process_util::ProcessMetrics::CreateProcessMetrics(process_));
-  process_util::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;
-}
-
-int32 Process::pid() const {
-  if (process_ == 0)
-    return 0;
-
-  return process_util::GetProcId(process_);
-}
-
-bool Process::is_current() const {
-  return process_ == GetCurrentProcess();
-}
-
-// static
-Process Process::Current() {
-  return Process(GetCurrentProcess());
-}
-