diff --git a/init/README.md b/init/README.md index d3dd73a56..99522b95e 100644 --- a/init/README.md +++ b/init/README.md @@ -203,7 +203,9 @@ runs the service. `writepid ` > Write the child's pid to the given files when it forks. Meant for - cgroup/cpuset usage. + cgroup/cpuset usage. If no files under /dev/cpuset/ are specified, but the + system property 'ro.cpuset.default' is set to a non-empty cpuset name (e.g. + '/foreground'), then the pid is written to file /dev/cpuset/_cpuset\_name_/tasks. `priority ` > Scheduling priority of the service process. This value has to be in range diff --git a/init/service.cpp b/init/service.cpp index ba901fdce..35aaa563a 100644 --- a/init/service.cpp +++ b/init/service.cpp @@ -630,6 +630,28 @@ bool Service::Start() { std::for_each(descriptors_.begin(), descriptors_.end(), std::bind(&DescriptorInfo::CreateAndPublish, std::placeholders::_1, scon)); + // See if there were "writepid" instructions to write to files under /dev/cpuset/. + auto cpuset_predicate = [](const std::string& path) { + return android::base::StartsWith(path, "/dev/cpuset/"); + }; + auto iter = std::find_if(writepid_files_.begin(), writepid_files_.end(), cpuset_predicate); + if (iter == writepid_files_.end()) { + // There were no "writepid" instructions for cpusets, check if the system default + // cpuset is specified to be used for the process. + std::string default_cpuset = property_get("ro.cpuset.default"); + if (!default_cpuset.empty()) { + // Make sure the cpuset name starts and ends with '/'. + // A single '/' means the 'root' cpuset. + if (default_cpuset.front() != '/') { + default_cpuset.insert(0, 1, '/'); + } + if (default_cpuset.back() != '/') { + default_cpuset.push_back('/'); + } + writepid_files_.push_back( + StringPrintf("/dev/cpuset%stasks", default_cpuset.c_str())); + } + } std::string pid_str = StringPrintf("%d", getpid()); for (const auto& file : writepid_files_) { if (!WriteStringToFile(pid_str, file)) {