Introduce additional service options for controlling memory cgroups.
The memcg.limit_percent option can be used to limit the cgroup's
max RSS to the given value as a percentage of the device's physical
memory. The memcg.limit_property option specifies the name of a
property that can be used to control the cgroup's max RSS. These
new options correspond to the arguments to the limitProcessMemory
function in frameworks/av/media/libmedia/MediaUtils.cpp; this will
allow us to add these options to the rc files for the programs that
call this function and then remove the callers in a later change.
There is also a change in semantics: the memcg.* options now have
an effect on all devices which support memory cgroups, not just
those with ro.config.low_ram or ro.config.per_app_memcg set to true.
This change also brings the semantics in line with the documentation,
so it looks like the previous semantics were unintentional.
Change-Id: I9495826de6e477b952e23866743b5fa600adcacb
Bug: 118642754
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 0a42053..9df8dd9 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -53,49 +53,31 @@
using namespace std::chrono_literals;
-#define MEM_CGROUP_PATH "/dev/memcg/apps"
-#define MEM_CGROUP_TASKS "/dev/memcg/apps/tasks"
-#define ACCT_CGROUP_PATH "/acct"
+static const char kCpuacctCgroup[] = "/acct";
+static const char kMemoryCgroup[] = "/dev/memcg/apps";
#define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs"
-std::once_flag init_path_flag;
-
-static const std::string& GetCgroupRootPath() {
- static std::string cgroup_root_path;
- std::call_once(init_path_flag, [&]() {
- // low-ram devices use per-app memcg by default, unlike high-end ones
- bool low_ram_device = GetBoolProperty("ro.config.low_ram", false);
- bool per_app_memcg =
- GetBoolProperty("ro.config.per_app_memcg", low_ram_device);
- if (per_app_memcg) {
- // Check if mem cgroup is mounted, only then check for
- // write-access to avoid SELinux denials
- cgroup_root_path =
- (access(MEM_CGROUP_TASKS, F_OK) || access(MEM_CGROUP_PATH, W_OK) ?
- ACCT_CGROUP_PATH : MEM_CGROUP_PATH);
- } else {
- cgroup_root_path = ACCT_CGROUP_PATH;
- }
- });
- return cgroup_root_path;
+static bool isMemoryCgroupSupported() {
+ static bool memcg_supported = !access("/dev/memcg/memory.limit_in_bytes", F_OK);
+ return memcg_supported;
}
-static std::string ConvertUidToPath(uid_t uid) {
- return StringPrintf("%s/uid_%d", GetCgroupRootPath().c_str(), uid);
+static std::string ConvertUidToPath(const char* cgroup, uid_t uid) {
+ return StringPrintf("%s/uid_%d", cgroup, uid);
}
-static std::string ConvertUidPidToPath(uid_t uid, int pid) {
- return StringPrintf("%s/uid_%d/pid_%d", GetCgroupRootPath().c_str(), uid, pid);
+static std::string ConvertUidPidToPath(const char* cgroup, uid_t uid, int pid) {
+ return StringPrintf("%s/uid_%d/pid_%d", cgroup, uid, pid);
}
-static int RemoveProcessGroup(uid_t uid, int pid) {
+static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid) {
int ret;
- auto uid_pid_path = ConvertUidPidToPath(uid, pid);
+ auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, pid);
ret = rmdir(uid_pid_path.c_str());
- auto uid_path = ConvertUidToPath(uid);
+ auto uid_path = ConvertUidToPath(cgroup, uid);
rmdir(uid_path.c_str());
return ret;
@@ -124,25 +106,26 @@
void removeAllProcessGroups()
{
LOG(VERBOSE) << "removeAllProcessGroups()";
- const auto& cgroup_root_path = GetCgroupRootPath();
- std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path.c_str()), closedir);
- if (root == NULL) {
- PLOG(ERROR) << "Failed to open " << cgroup_root_path;
- } else {
- dirent* dir;
- while ((dir = readdir(root.get())) != nullptr) {
- if (dir->d_type != DT_DIR) {
- continue;
- }
+ for (const char* cgroup_root_path : {kCpuacctCgroup, kMemoryCgroup}) {
+ std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path), closedir);
+ if (root == NULL) {
+ PLOG(ERROR) << "Failed to open " << cgroup_root_path;
+ } else {
+ dirent* dir;
+ while ((dir = readdir(root.get())) != nullptr) {
+ if (dir->d_type != DT_DIR) {
+ continue;
+ }
- if (!StartsWith(dir->d_name, "uid_")) {
- continue;
- }
+ if (!StartsWith(dir->d_name, "uid_")) {
+ continue;
+ }
- auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name);
- RemoveUidProcessGroups(path);
- LOG(VERBOSE) << "Removing " << path;
- if (rmdir(path.c_str()) == -1) PLOG(WARNING) << "Failed to remove " << path;
+ auto path = StringPrintf("%s/%s", cgroup_root_path, dir->d_name);
+ RemoveUidProcessGroups(path);
+ LOG(VERBOSE) << "Removing " << path;
+ if (rmdir(path.c_str()) == -1) PLOG(WARNING) << "Failed to remove " << path;
+ }
}
}
}
@@ -150,8 +133,8 @@
// Returns number of processes killed on success
// Returns 0 if there are no processes in the process cgroup left to kill
// Returns -1 on error
-static int DoKillProcessGroupOnce(uid_t uid, int initialPid, int signal) {
- auto path = ConvertUidPidToPath(uid, initialPid) + PROCESSGROUP_CGROUP_PROCS_FILE;
+static int DoKillProcessGroupOnce(const char* cgroup, uid_t uid, int initialPid, int signal) {
+ auto path = ConvertUidPidToPath(cgroup, uid, initialPid) + PROCESSGROUP_CGROUP_PROCS_FILE;
std::unique_ptr<FILE, decltype(&fclose)> fd(fopen(path.c_str(), "re"), fclose);
if (!fd) {
PLOG(WARNING) << "Failed to open process cgroup uid " << uid << " pid " << initialPid;
@@ -217,11 +200,16 @@
}
static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries) {
+ const char* cgroup =
+ (!access(ConvertUidPidToPath(kCpuacctCgroup, uid, initialPid).c_str(), F_OK))
+ ? kCpuacctCgroup
+ : kMemoryCgroup;
+
std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
int retry = retries;
int processes;
- while ((processes = DoKillProcessGroupOnce(uid, initialPid, signal)) > 0) {
+ while ((processes = DoKillProcessGroupOnce(cgroup, uid, initialPid, signal)) > 0) {
LOG(VERBOSE) << "Killed " << processes << " processes for processgroup " << initialPid;
if (retry > 0) {
std::this_thread::sleep_for(5ms);
@@ -251,7 +239,7 @@
LOG(INFO) << "Successfully killed process cgroup uid " << uid << " pid " << initialPid
<< " in " << static_cast<int>(ms) << "ms";
}
- return RemoveProcessGroup(uid, initialPid);
+ return RemoveProcessGroup(cgroup, uid, initialPid);
} else {
if (retries > 0) {
LOG(ERROR) << "Failed to kill process cgroup uid " << uid << " pid " << initialPid
@@ -285,16 +273,29 @@
return true;
}
-int createProcessGroup(uid_t uid, int initialPid)
+static bool isPerAppMemcgEnabled() {
+ static bool per_app_memcg =
+ GetBoolProperty("ro.config.per_app_memcg", GetBoolProperty("ro.config.low_ram", false));
+ return per_app_memcg;
+}
+
+int createProcessGroup(uid_t uid, int initialPid, bool memControl)
{
- auto uid_path = ConvertUidToPath(uid);
+ const char* cgroup;
+ if (isMemoryCgroupSupported() && (memControl || isPerAppMemcgEnabled())) {
+ cgroup = kMemoryCgroup;
+ } else {
+ cgroup = kCpuacctCgroup;
+ }
+
+ auto uid_path = ConvertUidToPath(cgroup, uid);
if (!MkdirAndChown(uid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
PLOG(ERROR) << "Failed to make and chown " << uid_path;
return -errno;
}
- auto uid_pid_path = ConvertUidPidToPath(uid, initialPid);
+ auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, initialPid);
if (!MkdirAndChown(uid_pid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
PLOG(ERROR) << "Failed to make and chown " << uid_pid_path;
@@ -313,12 +314,12 @@
}
static bool SetProcessGroupValue(uid_t uid, int pid, const std::string& file_name, int64_t value) {
- if (GetCgroupRootPath() != MEM_CGROUP_PATH) {
+ if (!isMemoryCgroupSupported()) {
PLOG(ERROR) << "Memcg is not mounted.";
return false;
}
- auto path = ConvertUidPidToPath(uid, pid) + file_name;
+ auto path = ConvertUidPidToPath(kMemoryCgroup, uid, pid) + file_name;
if (!WriteStringToFile(std::to_string(value), path)) {
PLOG(ERROR) << "Failed to write '" << value << "' to " << path;