1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "thread.h"
18
19#include <sys/time.h>
20#include <sys/resource.h>
21#include <limits.h>
22#include <errno.h>
23
24#include <cutils/sched_policy.h>
25#include <utils/threads.h>
26
27#include "base/macros.h"
28
29namespace art {
30
31// Conversion map for "nice" values.
32//
33// We use Android thread priority constants to be consistent with the rest
34// of the system.  In some cases adjacent entries may overlap.
35//
36static const int kNiceValues[10] = {
37  ANDROID_PRIORITY_LOWEST,                // 1 (MIN_PRIORITY)
38  ANDROID_PRIORITY_BACKGROUND + 6,
39  ANDROID_PRIORITY_BACKGROUND + 3,
40  ANDROID_PRIORITY_BACKGROUND,
41  ANDROID_PRIORITY_NORMAL,                // 5 (NORM_PRIORITY)
42  ANDROID_PRIORITY_NORMAL - 2,
43  ANDROID_PRIORITY_NORMAL - 4,
44  ANDROID_PRIORITY_URGENT_DISPLAY + 3,
45  ANDROID_PRIORITY_URGENT_DISPLAY + 2,
46  ANDROID_PRIORITY_URGENT_DISPLAY         // 10 (MAX_PRIORITY)
47};
48
49void Thread::SetNativePriority(int newPriority) {
50  if (newPriority < 1 || newPriority > 10) {
51    LOG(WARNING) << "bad priority " << newPriority;
52    newPriority = 5;
53  }
54
55  int newNice = kNiceValues[newPriority-1];
56  pid_t tid = GetTid();
57
58  // TODO: b/18249098 The code below is broken. It uses getpriority() as a proxy for whether a
59  // thread is already in the SP_FOREGROUND cgroup. This is not necessarily true for background
60  // processes, where all threads are in the SP_BACKGROUND cgroup. This means that callers will
61  // have to call setPriority twice to do what they want :
62  //
63  //     Thread.setPriority(Thread.MIN_PRIORITY);  // no-op wrt to cgroups
64  //     Thread.setPriority(Thread.MAX_PRIORITY);  // will actually change cgroups.
65  if (newNice >= ANDROID_PRIORITY_BACKGROUND) {
66    set_sched_policy(tid, SP_BACKGROUND);
67  } else if (getpriority(PRIO_PROCESS, tid) >= ANDROID_PRIORITY_BACKGROUND) {
68    set_sched_policy(tid, SP_FOREGROUND);
69  }
70
71  if (setpriority(PRIO_PROCESS, tid, newNice) != 0) {
72    PLOG(INFO) << *this << " setPriority(PRIO_PROCESS, " << tid << ", " << newNice << ") failed";
73  }
74}
75
76int Thread::GetNativePriority() {
77  errno = 0;
78  int native_priority = getpriority(PRIO_PROCESS, 0);
79  if (native_priority == -1 && errno != 0) {
80    PLOG(WARNING) << "getpriority failed";
81    return kNormThreadPriority;
82  }
83
84  int managed_priority = kMinThreadPriority;
85  for (size_t i = 0; i < arraysize(kNiceValues); i++) {
86    if (native_priority >= kNiceValues[i]) {
87      break;
88    }
89    managed_priority++;
90  }
91  if (managed_priority > kMaxThreadPriority) {
92    managed_priority = kMaxThreadPriority;
93  }
94  return managed_priority;
95}
96
97void Thread::SetUpAlternateSignalStack() {
98  // Bionic does this for us.
99}
100
101void Thread::TearDownAlternateSignalStack() {
102  // Bionic does this for us.
103}
104
105}  // namespace art
106