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
29 namespace 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 //
36 static 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
SetNativePriority(int newPriority)49 void 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
GetNativePriority()76 int 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
SetUpAlternateSignalStack()97 void Thread::SetUpAlternateSignalStack() {
98 // Bionic does this for us.
99 }
100
TearDownAlternateSignalStack()101 void Thread::TearDownAlternateSignalStack() {
102 // Bionic does this for us.
103 }
104
105 } // namespace art
106