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| 1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "base/process.h" | |
| 6 #include "base/logging.h" | |
| 7 #include "base/process_util.h" | |
| 8 #include "base/scoped_ptr.h" | |
| 9 | |
| 10 bool Process::IsProcessBackgrounded() { | |
| 11 DCHECK(process_); | |
| 12 DWORD priority = GetPriorityClass(process_); | |
| 13 if (priority == 0) | |
| 14 return false; // Failure case. | |
| 15 return priority == BELOW_NORMAL_PRIORITY_CLASS; | |
| 16 } | |
| 17 | |
| 18 bool Process::SetProcessBackgrounded(bool value) { | |
| 19 DCHECK(process_); | |
| 20 DWORD priority = value ? BELOW_NORMAL_PRIORITY_CLASS : NORMAL_PRIORITY_CLASS; | |
| 21 return (SetPriorityClass(process_, priority) != 0); | |
| 22 } | |
| 23 | |
| 24 // According to MSDN, these are the default values which XP | |
| 25 // uses to govern working set soft limits. | |
| 26 // http://msdn.microsoft.com/en-us/library/ms686234.aspx | |
| 27 static const int kWinDefaultMinSet = 50 * 4096; | |
| 28 static const int kWinDefaultMaxSet = 345 * 4096; | |
| 29 static const int kDampingFactor = 2; | |
| 30 | |
| 31 bool Process::ReduceWorkingSet() { | |
| 32 if (!process_) | |
| 33 return false; | |
| 34 // The idea here is that when we the process' working set has gone | |
| 35 // down, we want to release those pages to the OS quickly. However, | |
| 36 // when it is not going down, we want to be careful not to release | |
| 37 // too much back to the OS, as it could cause additional paging. | |
| 38 | |
| 39 // We use a damping function to lessen the working set over time. | |
| 40 // As the process grows/shrinks, this algorithm will lag with | |
| 41 // working set reduction. | |
| 42 // | |
| 43 // The intended algorithm is: | |
| 44 // TargetWorkingSetSize = (LastWorkingSet/2 + CurrentWorkingSet) /2 | |
| 45 | |
| 46 scoped_ptr<process_util::ProcessMetrics> metrics( | |
| 47 process_util::ProcessMetrics::CreateProcessMetrics(process_)); | |
| 48 process_util::WorkingSetKBytes working_set; | |
| 49 if (!metrics->GetWorkingSetKBytes(&working_set)) | |
| 50 return false; | |
| 51 | |
| 52 | |
| 53 // We want to compute the amount of working set that the process | |
| 54 // needs to keep in memory. Since other processes contain the | |
| 55 // pages which are shared, we don't need to reserve them in our | |
| 56 // process, the system already has them tagged. Keep in mind, we | |
| 57 // don't get to control *which* pages get released, but if we | |
| 58 // assume reasonable distribution of pages, this should generally | |
| 59 // be the right value. | |
| 60 size_t current_working_set_size = working_set.priv + | |
| 61 working_set.shareable; | |
| 62 | |
| 63 size_t max_size = current_working_set_size; | |
| 64 if (last_working_set_size_) | |
| 65 max_size = (max_size + last_working_set_size_) / 2; // Average. | |
| 66 max_size *= 1024; // Convert to KBytes. | |
| 67 last_working_set_size_ = current_working_set_size / kDampingFactor; | |
| 68 | |
| 69 BOOL rv = SetProcessWorkingSetSize(process_, kWinDefaultMinSet, max_size); | |
| 70 return rv == TRUE; | |
| 71 } | |
| 72 | |
| 73 bool Process::UnReduceWorkingSet() { | |
| 74 if (!process_) | |
| 75 return false; | |
| 76 | |
| 77 if (!last_working_set_size_) | |
| 78 return true; // There was nothing to undo. | |
| 79 | |
| 80 // We've had a reduced working set. Make sure we have lots of | |
| 81 // headroom now that we're active again. | |
| 82 size_t limit = last_working_set_size_ * kDampingFactor * 2 * 1024; | |
| 83 BOOL rv = SetProcessWorkingSetSize(process_, kWinDefaultMinSet, limit); | |
| 84 return rv == TRUE; | |
| 85 } | |
| 86 | |
| 87 bool Process::EmptyWorkingSet() { | |
| 88 if (!process_) | |
| 89 return false; | |
| 90 | |
| 91 BOOL rv = SetProcessWorkingSetSize(process_, -1, -1); | |
| 92 return rv == TRUE; | |
| 93 } | |
| 94 | |
| 95 int32 Process::pid() const { | |
| 96 if (process_ == 0) | |
| 97 return 0; | |
| 98 | |
| 99 return process_util::GetProcId(process_); | |
| 100 } | |
| 101 | |
| 102 bool Process::is_current() const { | |
| 103 return process_ == GetCurrentProcess(); | |
| 104 } | |
| 105 | |
| 106 // static | |
| 107 Process Process::Current() { | |
| 108 return Process(GetCurrentProcess()); | |
| 109 } | |
| 110 | |
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Chromium Code Reviews
Issue 6492:
Port parts of base/process_util to Linux. (Closed)
Base URL: http://src.chromium.org/svn/trunk/src/