这个方案有如下基本需求：
原理上因为修改代码涉及部分较多，因此共分3个部分：
由于修改中涉及代码量过大，这里拆分成两节进行展示。本章节主要针对第1部分修改进行说明。下一篇文章 👇
Android Framework 常见解决方案（25-2）定制CPUSET解决方案-system修改及编译部分调整
主要对第2和第3部分修改进行说明。
这里需要添加THREAD_GROUP_CUSTOM，与system中修改的SP_CUSTOM同步，数值需一致，需要在$AOSP/frameworks/base/core/java/android/os/Process.java文件中修改：
public class Process {
private static final String LOG_TAG = "Process";
/**
* An invalid UID value.
*/
public static final int INVALID_UID = -1;
//...
/**
* Thread group for RT app.
* @hide
**/
public static final int THREAD_GROUP_RT_APP = 6;
/**
* Thread group for bound foreground services that should
* have additional CPU restrictions during screen off
* @hide
**/
public static final int THREAD_GROUP_RESTRICTED = 7;
/**
* Thread Group for CUSTOM
* @hide
**/
public static final int THREAD_GROUP_CUSTOM = 8;
//...
}接下来需要添加SCHED_GROUP_CUSTOM相关配置。在$AOSP/frameworks/base/services/core/java/com/android/server/am/ProcessList.java文件中修改：
public final class ProcessList {
//...
// Activity manager's version of Process.THREAD_GROUP_BACKGROUND
static final int SCHED_GROUP_BACKGROUND = 0;
// Activity manager's version of Process.THREAD_GROUP_RESTRICTED
static final int SCHED_GROUP_RESTRICTED = 1;
// Activity manager's version of Process.THREAD_GROUP_DEFAULT
static final int SCHED_GROUP_DEFAULT = 2;
// Activity manager's version of Process.THREAD_GROUP_TOP_APP
public static final int SCHED_GROUP_TOP_APP = 3;
// Activity manager's version of Process.THREAD_GROUP_TOP_APP
// Disambiguate between actual top app and processes bound to the top app
static final int SCHED_GROUP_TOP_APP_BOUND = 4;
+ //add custom schedule group
+ static final int SCHED_GROUP_CUSTOM = 10;
//...
private static boolean writeProcessOomListToProto(ProtoOutputStream proto, long fieldId,
ActivityManagerService service, List<ProcessRecord> origList,
boolean inclDetails, String dumpPackage) {
//...
switch (state.getSetSchedGroup()) {
case SCHED_GROUP_BACKGROUND:
schedGroup = ProcessOomProto.SCHED_GROUP_BACKGROUND;
break;
case SCHED_GROUP_DEFAULT:
schedGroup = ProcessOomProto.SCHED_GROUP_DEFAULT;
break;
case SCHED_GROUP_TOP_APP:
schedGroup = ProcessOomProto.SCHED_GROUP_TOP_APP;
break;
case SCHED_GROUP_TOP_APP_BOUND:
schedGroup = ProcessOomProto.SCHED_GROUP_TOP_APP_BOUND;
+ case SCHED_GROUP_CUSTOM:
+ schedGroup = ProcessOomProto.SCHED_GROUP_CUSTOM;
+ break;
}
//...
}
//...
private static boolean dumpProcessOomList(PrintWriter pw,
ActivityManagerService service, List<ProcessRecord> origList,
String prefix, String normalLabel, String persistentLabel,
boolean inclDetails, String dumpPackage) {
//...
for (int i = list.size() - 1; i >= 0; i--) {
//...
switch (state.getSetSchedGroup()) {
case SCHED_GROUP_BACKGROUND:
schedGroup = 'b';
break;
case SCHED_GROUP_DEFAULT:
schedGroup = 'F';
break;
case SCHED_GROUP_TOP_APP:
schedGroup = 'T';
break;
case SCHED_GROUP_RESTRICTED:
schedGroup = 'R';
break;
case SCHED_GROUP_TOP_APP_BOUND:
schedGroup = 'B';
break;
+ case SCHED_GROUP_CUSTOM:
+ schedGroup = 'C';
+ break;
default:
schedGroup = '?';
break;
}
}添加SCHED_GROUP_CUSTOM，与ProcessList.java中同步。在$AOSP/frameworks/base/core/proto/android/server/activitymanagerservice.proto文件中修改：
//...
message ProcessOomProto {
//...
enum SchedGroup {
SCHED_GROUP_UNKNOWN = -1;
SCHED_GROUP_BACKGROUND = 0;
SCHED_GROUP_DEFAULT = 1;
SCHED_GROUP_TOP_APP = 2;
SCHED_GROUP_TOP_APP_BOUND = 3;
+ SCHED_GROUP_CUSTOM = 10;
}
?为适配之前的适配SP_CUSTOM，同时契合之前1中修改的task_profile.json文件中的配置，在AOSP/frameworks/base/core/jni/android_util_Process.cpp文件中修改：
//修改android_os_Process_setProcessGroup，适配SP_CUSTOM
void android_os_Process_setProcessGroup(JNIEnv* env, jobject clazz, int pid, jint grp)
{
ALOGV("%s pid=%d grp=%" PRId32, __func__, pid, grp);
//...
while ((de = readdir(d))) {
//...
// grp != SP_BACKGROUND. Only change the cpuset cgroup for low priority thread, so it could
// preserve it sched policy profile setting.
if (t_pri >= ANDROID_PRIORITY_BACKGROUND) {
switch (grp) {
case SP_SYSTEM:
taskprofile = "ServiceCapacityLow";
break;
case SP_RESTRICTED:
taskprofile = "ServiceCapacityRestricted";
break;
case SP_FOREGROUND:
case SP_AUDIO_APP:
case SP_AUDIO_SYS:
taskprofile = "ProcessCapacityHigh";
break;
case SP_TOP_APP:
taskprofile = "ProcessCapacityMax";
break;
+ case SP_CUSTOM:
+ taskprofile = "CustomPerformance";
+ break;
default:
taskprofile = "ProcessCapacityNormal";
break;
}
if (!SetTaskProfiles(t_pid, {taskprofile}, true)) {
signalExceptionForGroupError(env, errno ? errno : EPERM, t_pid);
break;
}
// Change the cpuset policy profile for non-low priority thread according to the grp
} else {
if (!SetTaskProfiles(t_pid, {get_cpuset_policy_profile_name((SchedPolicy)grp)}, true)) {
signalExceptionForGroupError(env, errno ? errno : EPERM, t_pid);
break;
}
}
}
closedir(d);
}
//修改get_cpuset_cores_for_policy，适配SP_CUSTOM
static void get_cpuset_cores_for_policy(SchedPolicy policy, cpu_set_t *cpu_set)
{
FILE *file;
std::string filename;
CPU_ZERO(cpu_set);
switch (policy) {
case SP_BACKGROUND:
if (!CgroupGetAttributePath("LowCapacityCPUs", &filename)) {
return;
}
break;
case SP_FOREGROUND:
if (!CgroupGetAttributePath("HighCapacityCPUs", &filename)) {
return;
}
break;
case SP_AUDIO_APP:
case SP_AUDIO_SYS:
if (!CgroupGetAttributePath("AudioAppCapacityCPUs", &filename)) {
return;
}
if (access(filename.c_str(), F_OK) != 0) {
if (!CgroupGetAttributePath("HighCapacityCPUs", &filename)) {
return;
}
}
break;
case SP_RT_APP:
if (!CgroupGetAttributePath("HighCapacityCPUs", &filename)) {
return;
}
break;
case SP_TOP_APP:
if (!CgroupGetAttributePath("MaxCapacityCPUs", &filename)) {
return;
}
break;
+ case SP_CUSTOM:
+ if (!CgroupGetAttributePath("CustomCPUs", &filename)) {
+ return;
+ }
+ break;
default:
return;
}
file = fopen(filename.c_str(), "re");
if (file != NULL) {
// Parse cpus string
char *line = NULL;
size_t len = 0;
ssize_t num_read = getline(&line, &len, file);
fclose (file);
if (num_read > 0) {
parse_cpuset_cpus(line, cpu_set);
} else {
ALOGE("Failed to read %s", filename.c_str());
}
free(line);
}
return;
}在这里使用com.ags.test应用demo进行测试后验证。根据自己需要调整即可。主要保证该应用始终在SCHED_GROUP_CUSTOM中，不切换到其它schedule group中，同时建立SCHED_GROUP_CUSTOM和THREAD_GROUP_CUSTOM之间的联系。在$AOSP/frameworks/base/services/core/java/com/android/server/am/OomAdjuster.java文件中修改：
//...
+import static android.os.Process.THREAD_GROUP_CUSTOM;
//...
public class OomAdjuster {
//...
private boolean applyOomAdjLSP(ProcessRecord app, boolean doingAll, long now,
long nowElapsed) {
boolean success = true;
final ProcessStateRecord state = app.mState;
if (state.getCurRawAdj() != state.getSetRawAdj()) {
state.setSetRawAdj(state.getCurRawAdj());
}
//...
int processGroup;
switch (curSchedGroup) {
case ProcessList.SCHED_GROUP_BACKGROUND:
processGroup = THREAD_GROUP_BACKGROUND;
break;
case ProcessList.SCHED_GROUP_TOP_APP:
case ProcessList.SCHED_GROUP_TOP_APP_BOUND:
processGroup = THREAD_GROUP_TOP_APP;
break;
case ProcessList.SCHED_GROUP_RESTRICTED:
processGroup = THREAD_GROUP_RESTRICTED;
break;
+ case ProcessList.SCHED_GROUP_CUSTOM:
+ processGroup = THREAD_GROUP_CUSTOM;
+ break;
default:
processGroup = THREAD_GROUP_DEFAULT;
break;
}
//...
}
//...
private boolean computeOomAdjLSP(ProcessRecord app, int cachedAdj,
ProcessRecord topApp, boolean doingAll, long now, boolean cycleReEval,
boolean computeClients) {
//...
+ if(app.processName.equals("com.ags.test")){
+ schedGroup = ProcessList.SCHED_GROUP_CUSTOM;
+ }
// Do final modification to adj. Everything we do between here and applying
// the final setAdj must be done in this function, because we will also use
// it when computing the final cached adj later. Note that we don't need to
// worry about this for max adj above, since max adj will always be used to
// keep it out of the cached vaues.
state.setCurAdj(psr.modifyRawOomAdj(adj));
state.setCurCapability(capability);
state.setCurrentSchedulingGroup(schedGroup);
state.setCurProcState(procState);
state.setCurRawProcState(procState);
state.updateLastInvisibleTime(hasVisibleActivities);
state.setHasForegroundActivities(foregroundActivities);
state.setCompletedAdjSeq(mAdjSeq);
// if curAdj or curProcState improved, then this process was promoted
return state.getCurAdj() < prevAppAdj || state.getCurProcState() < prevProcState
|| state.getCurCapability() != prevCapability;
}
//...
}修改SpecializeCommon，主要是在创建进程时直接设置cpuset，在$AOSP/frameworks/base/core/jni/android_util_Process.cpp文件中修改：
static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids, jint runtime_flags,
jobjectArray rlimits, jlong permitted_capabilities,
jlong effective_capabilities, jint mount_external,
jstring managed_se_info, jstring managed_nice_name,
bool is_system_server, bool is_child_zygote,
jstring managed_instruction_set, jstring managed_app_data_dir,
bool is_top_app, jobjectArray pkg_data_info_list,
jobjectArray allowlisted_data_info_list, bool mount_data_dirs,
bool mount_storage_dirs) {
const char* process_name = is_system_server ? "system_server" : "zygote";
auto fail_fn = std::bind(ZygoteFailure, env, process_name, managed_nice_name, _1);
auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);
//...
if (setresgid(gid, gid, gid) == -1) {
fail_fn(CREATE_ERROR("setresgid(%d) failed: %s", gid, strerror(errno)));
}
// Must be called when the new process still has CAP_SYS_ADMIN, in this case,
// before changing uid from 0, which clears capabilities. The other
// alternative is to call prctl(PR_SET_NO_NEW_PRIVS, 1) afterward, but that
// breaks SELinux domain transition (see b/71859146). As the result,
// privileged syscalls used below still need to be accessible in app process.
SetUpSeccompFilter(uid, is_child_zygote);
// Must be called before losing the permission to set scheduler policy.
SetSchedulerPolicy(fail_fn, is_top_app);
+ if (nice_name.has_value()) {
+ if(strncmp(nice_name.value().c_str(),"com.ags.test",sizeof("com.ags.test"))==0){
+#if 1 //set_cpuset_policy方案
+ int ret = set_cpuset_policy(0, SP_CUSTOM);
+ if (ret != 0) {
+ ALOGE("set_cpuset_policy call default failure,ret:%d,(%s)", ret,nice_name.value().c_str());
+ }else{
+ ALOGD("set_cpuset_policy call default success,ret==0,(%s)", nice_name.value().c_str());
+ }
+#else //set_sched_policy兼容方案
+ int ret = set_sched_policy(0, SP_CUSTOM);
+ if (ret != 0) {
+ ALOGE("set_sched_policy call default failure,ret:%d,(%s)", ret,nice_name.value().c_str());
+ }
+ else{
+ ALOGD("set_sched_policy call default success,ret==0,(%s)", nice_name.value().c_str());
+ }
+#endif
+ }
+ }
//...
}
至此，framework层相关修改就结束了。主要添加SCHED_GROUP_CUSTOM、THREAD_GROUP_CUSTOM（THREAD_GROUP_对应SP_）即以和对应SP_CUSTOM之间的联系建立，且支持开机启动后直接过滤包，进行CPUSET的设置。同时applyOomAdjLSP的判定保持不变，不受其他CPUSET的影响。