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platform_system_core/libprocessgroup/processgroup.cpp
T.J. Mercier a103630b5c libprocessgroup: Use cgroup.kill 
By using cgroup.kill we don't need to read cgroup.procs at all for
SIGKILLs, which is more efficient and should help reduce CPU contention
and cgroup lock contention. Fallback to cgroup.procs if we encounter an
error trying to use cgroup.kill, but if cgroup.kill fails it's likely
that cgroup.procs will too.

Bug: 239829790
Test: atest StagedRollbackTest:com.android.tests.rollback.host.StagedRollbackTest#testNativeWatchdogTriggersRebootlessApexRollback
Change-Id: I9da67efd00af49b7b4b502fb742c1095d5c7b9e9
2023-12-14 21:52:13 +00:00

758 lines
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/*
* Copyright 2014 Google, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//#define LOG_NDEBUG 0
#define LOG_TAG "libprocessgroup"
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <chrono>
#include <cstring>
#include <map>
#include <memory>
#include <mutex>
#include <set>
#include <string>
#include <thread>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <cutils/android_filesystem_config.h>
#include <processgroup/processgroup.h>
#include <task_profiles.h>
using android::base::GetBoolProperty;
using android::base::StartsWith;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
using namespace std::chrono_literals;
#define PROCESSGROUP_CGROUP_PROCS_FILE "cgroup.procs"
#define PROCESSGROUP_CGROUP_KILL_FILE "cgroup.kill"
#define PROCESSGROUP_CGROUP_EVENTS_FILE "cgroup.events"
bool CgroupsAvailable() {
static bool cgroups_available = access("/proc/cgroups", F_OK) == 0;
return cgroups_available;
}
bool CgroupGetControllerPath(const std::string& cgroup_name, std::string* path) {
auto controller = CgroupMap::GetInstance().FindController(cgroup_name);
if (!controller.HasValue()) {
return false;
}
if (path) {
*path = controller.path();
}
return true;
}
static std::string ConvertUidToPath(const char* cgroup, uid_t uid) {
return StringPrintf("%s/uid_%u", cgroup, uid);
}
static std::string ConvertUidPidToPath(const char* cgroup, uid_t uid, int pid) {
return StringPrintf("%s/uid_%u/pid_%d", cgroup, uid, pid);
}
static bool CgroupKillAvailable() {
static std::once_flag f;
static bool cgroup_kill_available = false;
std::call_once(f, []() {
std::string cg_kill;
CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &cg_kill);
// cgroup.kill is not on the root cgroup, so check a non-root cgroup that should always
// exist
cg_kill = ConvertUidToPath(cg_kill.c_str(), AID_ROOT) + '/' + PROCESSGROUP_CGROUP_KILL_FILE;
cgroup_kill_available = access(cg_kill.c_str(), F_OK) == 0;
});
return cgroup_kill_available;
}
static bool CgroupGetMemcgAppsPath(std::string* path) {
CgroupController controller = CgroupMap::GetInstance().FindController("memory");
if (!controller.HasValue()) {
return false;
}
if (path) {
*path = controller.path();
if (controller.version() == 1) {
*path += "/apps";
}
}
return true;
}
bool CgroupGetControllerFromPath(const std::string& path, std::string* cgroup_name) {
auto controller = CgroupMap::GetInstance().FindControllerByPath(path);
if (!controller.HasValue()) {
return false;
}
if (cgroup_name) {
*cgroup_name = controller.name();
}
return true;
}
bool CgroupGetAttributePath(const std::string& attr_name, std::string* path) {
const TaskProfiles& tp = TaskProfiles::GetInstance();
const IProfileAttribute* attr = tp.GetAttribute(attr_name);
if (attr == nullptr) {
return false;
}
if (path) {
*path = StringPrintf("%s/%s", attr->controller()->path(), attr->file_name().c_str());
}
return true;
}
bool CgroupGetAttributePathForTask(const std::string& attr_name, int tid, std::string* path) {
const TaskProfiles& tp = TaskProfiles::GetInstance();
const IProfileAttribute* attr = tp.GetAttribute(attr_name);
if (attr == nullptr) {
return false;
}
if (!attr->GetPathForTask(tid, path)) {
LOG(ERROR) << "Failed to find cgroup for tid " << tid;
return false;
}
return true;
}
bool UsePerAppMemcg() {
bool low_ram_device = GetBoolProperty("ro.config.low_ram", false);
return GetBoolProperty("ro.config.per_app_memcg", low_ram_device);
}
static bool isMemoryCgroupSupported() {
static bool memcg_supported = CgroupMap::GetInstance().FindController("memory").IsUsable();
return memcg_supported;
}
void DropTaskProfilesResourceCaching() {
TaskProfiles::GetInstance().DropResourceCaching(ProfileAction::RCT_TASK);
TaskProfiles::GetInstance().DropResourceCaching(ProfileAction::RCT_PROCESS);
}
bool SetProcessProfiles(uid_t uid, pid_t pid, const std::vector<std::string>& profiles) {
return TaskProfiles::GetInstance().SetProcessProfiles(
uid, pid, std::span<const std::string>(profiles), false);
}
bool SetProcessProfiles(uid_t uid, pid_t pid, std::initializer_list<std::string_view> profiles) {
return TaskProfiles::GetInstance().SetProcessProfiles(
uid, pid, std::span<const std::string_view>(profiles), false);
}
bool SetProcessProfiles(uid_t uid, pid_t pid, std::span<const std::string_view> profiles) {
return TaskProfiles::GetInstance().SetProcessProfiles(uid, pid, profiles, false);
}
bool SetProcessProfilesCached(uid_t uid, pid_t pid, const std::vector<std::string>& profiles) {
return TaskProfiles::GetInstance().SetProcessProfiles(
uid, pid, std::span<const std::string>(profiles), true);
}
bool SetTaskProfiles(int tid, const std::vector<std::string>& profiles, bool use_fd_cache) {
return TaskProfiles::GetInstance().SetTaskProfiles(tid, std::span<const std::string>(profiles),
use_fd_cache);
}
bool SetTaskProfiles(int tid, std::initializer_list<std::string_view> profiles, bool use_fd_cache) {
return TaskProfiles::GetInstance().SetTaskProfiles(
tid, std::span<const std::string_view>(profiles), use_fd_cache);
}
bool SetTaskProfiles(int tid, std::span<const std::string_view> profiles, bool use_fd_cache) {
return TaskProfiles::GetInstance().SetTaskProfiles(tid, profiles, use_fd_cache);
}
// C wrapper for SetProcessProfiles.
// No need to have this in the header file because this function is specifically for crosvm. Crosvm
// which is written in Rust has its own declaration of this foreign function and doesn't rely on the
// header. See
// https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3574427/5/src/linux/android.rs#12
extern "C" bool android_set_process_profiles(uid_t uid, pid_t pid, size_t num_profiles,
const char* profiles[]) {
std::vector<std::string_view> profiles_;
profiles_.reserve(num_profiles);
for (size_t i = 0; i < num_profiles; i++) {
profiles_.emplace_back(profiles[i]);
}
return SetProcessProfiles(uid, pid, std::span<const std::string_view>(profiles_));
}
bool SetUserProfiles(uid_t uid, const std::vector<std::string>& profiles) {
return TaskProfiles::GetInstance().SetUserProfiles(uid, std::span<const std::string>(profiles),
false);
}
static int RemoveCgroup(const char* cgroup, uid_t uid, int pid) {
auto path = ConvertUidPidToPath(cgroup, uid, pid);
int ret = TEMP_FAILURE_RETRY(rmdir(path.c_str()));
if (!ret && uid >= AID_ISOLATED_START && uid <= AID_ISOLATED_END) {
// Isolated UIDs are unlikely to be reused soon after removal,
// so free up the kernel resources for the UID level cgroup.
path = ConvertUidToPath(cgroup, uid);
ret = TEMP_FAILURE_RETRY(rmdir(path.c_str()));
}
if (ret < 0 && errno == ENOENT) {
// This function is idempoetent, but still warn here.
LOG(WARNING) << "RemoveCgroup: " << path << " does not exist.";
ret = 0;
}
return ret;
}
static bool RemoveEmptyUidCgroups(const std::string& uid_path) {
std::unique_ptr<DIR, decltype(&closedir)> uid(opendir(uid_path.c_str()), closedir);
bool empty = true;
if (uid != NULL) {
dirent* dir;
while ((dir = readdir(uid.get())) != nullptr) {
if (dir->d_type != DT_DIR) {
continue;
}
if (!StartsWith(dir->d_name, "pid_")) {
continue;
}
auto path = StringPrintf("%s/%s", uid_path.c_str(), dir->d_name);
LOG(VERBOSE) << "Removing " << path;
if (rmdir(path.c_str()) == -1) {
if (errno != EBUSY) {
PLOG(WARNING) << "Failed to remove " << path;
}
empty = false;
}
}
}
return empty;
}
void removeAllEmptyProcessGroups() {
LOG(VERBOSE) << "removeAllEmptyProcessGroups()";
std::vector<std::string> cgroups;
std::string path, memcg_apps_path;
if (CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &path)) {
cgroups.push_back(path);
}
if (CgroupGetMemcgAppsPath(&memcg_apps_path) && memcg_apps_path != path) {
cgroups.push_back(memcg_apps_path);
}
for (std::string cgroup_root_path : cgroups) {
std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path.c_str()), closedir);
if (root == NULL) {
PLOG(ERROR) << __func__ << " 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;
}
auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name);
if (!RemoveEmptyUidCgroups(path)) {
LOG(VERBOSE) << "Skip removing " << path;
continue;
}
LOG(VERBOSE) << "Removing " << path;
if (rmdir(path.c_str()) == -1 && errno != EBUSY) {
PLOG(WARNING) << "Failed to remove " << path;
}
}
}
}
}
/**
* Process groups are primarily created by the Zygote, meaning that uid/pid groups are created by
* the user root. Ownership for the newly created cgroup and all of its files must thus be
* transferred for the user/group passed as uid/gid before system_server can properly access them.
*/
static bool MkdirAndChown(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
if (mkdir(path.c_str(), mode) == -1) {
if (errno == EEXIST) {
// Directory already exists and permissions have been set at the time it was created
return true;
}
return false;
}
auto dir = std::unique_ptr<DIR, decltype(&closedir)>(opendir(path.c_str()), closedir);
if (dir == NULL) {
PLOG(ERROR) << "opendir failed for " << path;
goto err;
}
struct dirent* dir_entry;
while ((dir_entry = readdir(dir.get()))) {
if (!strcmp("..", dir_entry->d_name)) {
continue;
}
std::string file_path = path + "/" + dir_entry->d_name;
if (lchown(file_path.c_str(), uid, gid) < 0) {
PLOG(ERROR) << "lchown failed for " << file_path;
goto err;
}
if (fchmodat(AT_FDCWD, file_path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
PLOG(ERROR) << "fchmodat failed for " << file_path;
goto err;
}
}
return true;
err:
int saved_errno = errno;
rmdir(path.c_str());
errno = saved_errno;
return false;
}
bool sendSignalToProcessGroup(uid_t uid, int initialPid, int signal) {
std::set<pid_t> pgids, pids;
if (CgroupsAvailable()) {
std::string hierarchy_root_path, cgroup_v2_path;
CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &hierarchy_root_path);
cgroup_v2_path = ConvertUidPidToPath(hierarchy_root_path.c_str(), uid, initialPid);
if (signal == SIGKILL && CgroupKillAvailable()) {
LOG(VERBOSE) << "Using " << PROCESSGROUP_CGROUP_KILL_FILE << " to SIGKILL "
<< cgroup_v2_path;
// We need to kill the process group in addition to the cgroup. For normal apps they
// should completely overlap, but system_server kills depend on process group kills to
// take down apps which are in their own cgroups and not individually targeted.
if (kill(-initialPid, signal) == -1 && errno != ESRCH) {
PLOG(WARNING) << "kill(" << -initialPid << ", " << signal << ") failed";
}
const std::string killfilepath = cgroup_v2_path + '/' + PROCESSGROUP_CGROUP_KILL_FILE;
if (WriteStringToFile("1", killfilepath)) {
return true;
} else {
PLOG(ERROR) << "Failed to write 1 to " << killfilepath;
// Fallback to cgroup.procs below
}
}
// Since cgroup.kill only sends SIGKILLs, we read cgroup.procs to find each process to
// signal individually. This is more costly than using cgroup.kill for SIGKILLs.
LOG(VERBOSE) << "Using " << PROCESSGROUP_CGROUP_PROCS_FILE << " to signal (" << signal
<< ") " << cgroup_v2_path;
// We separate all of the pids in the cgroup into those pids that are also the leaders of
// process groups (stored in the pgids set) and those that are not (stored in the pids set).
const auto procsfilepath = cgroup_v2_path + '/' + PROCESSGROUP_CGROUP_PROCS_FILE;
std::unique_ptr<FILE, decltype(&fclose)> fp(fopen(procsfilepath.c_str(), "re"), fclose);
if (!fp) {
// This should only happen if the cgroup has already been removed with a successful call
// to killProcessGroup. Callers should only retry sendSignalToProcessGroup or
// killProcessGroup calls if they fail without ENOENT.
PLOG(ERROR) << "Failed to open " << procsfilepath;
kill(-initialPid, signal);
return false;
}
pid_t pid;
bool file_is_empty = true;
while (fscanf(fp.get(), "%d\n", &pid) == 1 && pid >= 0) {
file_is_empty = false;
if (pid == 0) {
// Should never happen... but if it does, trying to kill this
// will boomerang right back and kill us! Let's not let that happen.
LOG(WARNING)
<< "Yikes, we've been told to kill pid 0! How about we don't do that?";
continue;
}
pid_t pgid = getpgid(pid);
if (pgid == -1) PLOG(ERROR) << "getpgid(" << pid << ") failed";
if (pgid == pid) {
pgids.emplace(pid);
} else {
pids.emplace(pid);
}
}
if (!file_is_empty) {
// Erase all pids that will be killed when we kill the process groups.
for (auto it = pids.begin(); it != pids.end();) {
pid_t pgid = getpgid(*it);
if (pgids.count(pgid) == 1) {
it = pids.erase(it);
} else {
++it;
}
}
}
}
pgids.emplace(initialPid);
// Kill all process groups.
for (const auto pgid : pgids) {
LOG(VERBOSE) << "Killing process group " << -pgid << " in uid " << uid
<< " as part of process cgroup " << initialPid;
if (kill(-pgid, signal) == -1 && errno != ESRCH) {
PLOG(WARNING) << "kill(" << -pgid << ", " << signal << ") failed";
}
}
// Kill remaining pids.
for (const auto pid : pids) {
LOG(VERBOSE) << "Killing pid " << pid << " in uid " << uid << " as part of process cgroup "
<< initialPid;
if (kill(pid, signal) == -1 && errno != ESRCH) {
PLOG(WARNING) << "kill(" << pid << ", " << signal << ") failed";
}
}
return true;
}
template <typename T>
static std::chrono::milliseconds toMillisec(T&& duration) {
return std::chrono::duration_cast<std::chrono::milliseconds>(duration);
}
enum class populated_status
{
populated,
not_populated,
error
};
static populated_status cgroupIsPopulated(int events_fd) {
const std::string POPULATED_KEY("populated ");
const std::string::size_type MAX_EVENTS_FILE_SIZE = 32;
std::string buf;
buf.resize(MAX_EVENTS_FILE_SIZE);
ssize_t len = TEMP_FAILURE_RETRY(pread(events_fd, buf.data(), buf.size(), 0));
if (len == -1) {
PLOG(ERROR) << "Could not read cgroup.events: ";
// Potentially ENODEV if the cgroup has been removed since we opened this file, but that
// shouldn't have happened yet.
return populated_status::error;
}
if (len == 0) {
LOG(ERROR) << "cgroup.events EOF";
return populated_status::error;
}
buf.resize(len);
const std::string::size_type pos = buf.find(POPULATED_KEY);
if (pos == std::string::npos) {
LOG(ERROR) << "Could not find populated key in cgroup.events";
return populated_status::error;
}
if (pos + POPULATED_KEY.size() + 1 > len) {
LOG(ERROR) << "Partial read of cgroup.events";
return populated_status::error;
}
return buf[pos + POPULATED_KEY.size()] == '1' ?
populated_status::populated : populated_status::not_populated;
}
// The default timeout of 2200ms comes from the default number of retries in a previous
// implementation of this function. The default retry value was 40 for killing and 400 for cgroup
// removal with 5ms sleeps between each retry.
static int KillProcessGroup(
uid_t uid, int initialPid, int signal, bool once = false,
std::chrono::steady_clock::time_point until = std::chrono::steady_clock::now() + 2200ms) {
CHECK_GE(uid, 0);
CHECK_GT(initialPid, 0);
// Always attempt to send a kill signal to at least the initialPid, at least once, regardless of
// whether its cgroup exists or not. This should only be necessary if a bug results in the
// migration of the targeted process out of its cgroup, which we will also attempt to kill.
const bool signal_ret = sendSignalToProcessGroup(uid, initialPid, signal);
if (!CgroupsAvailable() || !signal_ret) return signal_ret ? 0 : -1;
std::string hierarchy_root_path;
CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &hierarchy_root_path);
const std::string cgroup_v2_path =
ConvertUidPidToPath(hierarchy_root_path.c_str(), uid, initialPid);
const std::string eventsfile = cgroup_v2_path + '/' + PROCESSGROUP_CGROUP_EVENTS_FILE;
android::base::unique_fd events_fd(open(eventsfile.c_str(), O_RDONLY));
if (events_fd.get() == -1) {
PLOG(WARNING) << "Error opening " << eventsfile << " for KillProcessGroup";
return -1;
}
struct pollfd fds = {
.fd = events_fd,
.events = POLLPRI,
};
const std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
// The primary reason to loop here is to capture any new forks or migrations that could occur
// after we send signals to the original set of processes, but before all of those processes
// exit and the cgroup becomes unpopulated, or before we remove the cgroup. We try hard to
// ensure this completes successfully to avoid permanent memory leaks, but we still place a
// large default upper bound on the amount of time we spend in this loop. The amount of CPU
// contention, and the amount of work that needs to be done in do_exit for each process
// determines how long this will take.
int ret;
do {
populated_status populated;
while ((populated = cgroupIsPopulated(events_fd.get())) == populated_status::populated &&
std::chrono::steady_clock::now() < until) {
sendSignalToProcessGroup(uid, initialPid, signal);
if (once) {
populated = cgroupIsPopulated(events_fd.get());
break;
}
const std::chrono::steady_clock::time_point poll_start =
std::chrono::steady_clock::now();
if (poll_start < until)
ret = TEMP_FAILURE_RETRY(poll(&fds, 1, toMillisec(until - poll_start).count()));
if (ret == -1) {
// Fallback to 5ms sleeps if poll fails
PLOG(ERROR) << "Poll on " << eventsfile << "failed";
const std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
if (now < until)
std::this_thread::sleep_for(std::min(5ms, toMillisec(until - now)));
}
LOG(VERBOSE) << "Waited "
<< toMillisec(std::chrono::steady_clock::now() - poll_start).count()
<< " ms for " << eventsfile << " poll";
}
const std::chrono::milliseconds kill_duration =
toMillisec(std::chrono::steady_clock::now() - start);
if (populated == populated_status::populated) {
LOG(WARNING) << "Still waiting on process(es) to exit for cgroup " << cgroup_v2_path
<< " after " << kill_duration.count() << " ms";
// We'll still try the cgroup removal below which we expect to log an error.
} else if (populated == populated_status::not_populated) {
LOG(VERBOSE) << "Killed all processes under cgroup " << cgroup_v2_path
<< " after " << kill_duration.count() << " ms";
}
ret = RemoveCgroup(hierarchy_root_path.c_str(), uid, initialPid);
if (ret)
PLOG(ERROR) << "Unable to remove cgroup " << cgroup_v2_path;
else
LOG(INFO) << "Removed cgroup " << cgroup_v2_path;
if (isMemoryCgroupSupported() && UsePerAppMemcg()) {
// This per-application memcg v1 case should eventually be removed after migration to
// memcg v2.
std::string memcg_apps_path;
if (CgroupGetMemcgAppsPath(&memcg_apps_path) &&
(ret = RemoveCgroup(memcg_apps_path.c_str(), uid, initialPid)) < 0) {
const auto memcg_v1_cgroup_path =
ConvertUidPidToPath(memcg_apps_path.c_str(), uid, initialPid);
PLOG(ERROR) << "Unable to remove memcg v1 cgroup " << memcg_v1_cgroup_path;
}
}
if (once) break;
if (std::chrono::steady_clock::now() >= until) break;
} while (ret && errno == EBUSY);
return ret;
}
int killProcessGroup(uid_t uid, int initialPid, int signal) {
return KillProcessGroup(uid, initialPid, signal);
}
int killProcessGroupOnce(uid_t uid, int initialPid, int signal) {
return KillProcessGroup(uid, initialPid, signal, true);
}
static int createProcessGroupInternal(uid_t uid, int initialPid, std::string cgroup,
bool activate_controllers) {
auto uid_path = ConvertUidToPath(cgroup.c_str(), uid);
struct stat cgroup_stat;
mode_t cgroup_mode = 0750;
uid_t cgroup_uid = AID_SYSTEM;
gid_t cgroup_gid = AID_SYSTEM;
int ret = 0;
if (stat(cgroup.c_str(), &cgroup_stat) < 0) {
PLOG(ERROR) << "Failed to get stats for " << cgroup;
} else {
cgroup_mode = cgroup_stat.st_mode;
cgroup_uid = cgroup_stat.st_uid;
cgroup_gid = cgroup_stat.st_gid;
}
if (!MkdirAndChown(uid_path, cgroup_mode, cgroup_uid, cgroup_gid)) {
PLOG(ERROR) << "Failed to make and chown " << uid_path;
return -errno;
}
if (activate_controllers) {
ret = CgroupMap::GetInstance().ActivateControllers(uid_path);
if (ret) {
LOG(ERROR) << "Failed to activate controllers in " << uid_path;
return ret;
}
}
auto uid_pid_path = ConvertUidPidToPath(cgroup.c_str(), uid, initialPid);
if (!MkdirAndChown(uid_pid_path, cgroup_mode, cgroup_uid, cgroup_gid)) {
PLOG(ERROR) << "Failed to make and chown " << uid_pid_path;
return -errno;
}
auto uid_pid_procs_file = uid_pid_path + '/' + PROCESSGROUP_CGROUP_PROCS_FILE;
if (!WriteStringToFile(std::to_string(initialPid), uid_pid_procs_file)) {
ret = -errno;
PLOG(ERROR) << "Failed to write '" << initialPid << "' to " << uid_pid_procs_file;
}
return ret;
}
int createProcessGroup(uid_t uid, int initialPid, bool memControl) {
CHECK_GE(uid, 0);
CHECK_GT(initialPid, 0);
if (memControl && !UsePerAppMemcg()) {
LOG(ERROR) << "service memory controls are used without per-process memory cgroup support";
return -EINVAL;
}
if (std::string memcg_apps_path;
isMemoryCgroupSupported() && UsePerAppMemcg() && CgroupGetMemcgAppsPath(&memcg_apps_path)) {
// Note by bvanassche: passing 'false' as fourth argument below implies that the v1
// hierarchy is used. It is not clear to me whether the above conditions guarantee that the
// v1 hierarchy is used.
int ret = createProcessGroupInternal(uid, initialPid, memcg_apps_path, false);
if (ret != 0) {
return ret;
}
}
std::string cgroup;
CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &cgroup);
return createProcessGroupInternal(uid, initialPid, cgroup, true);
}
static bool SetProcessGroupValue(int tid, const std::string& attr_name, int64_t value) {
if (!isMemoryCgroupSupported()) {
LOG(ERROR) << "Memcg is not mounted.";
return false;
}
std::string path;
if (!CgroupGetAttributePathForTask(attr_name, tid, &path)) {
LOG(ERROR) << "Failed to find attribute '" << attr_name << "'";
return false;
}
if (!WriteStringToFile(std::to_string(value), path)) {
PLOG(ERROR) << "Failed to write '" << value << "' to " << path;
return false;
}
return true;
}
bool setProcessGroupSwappiness(uid_t, int pid, int swappiness) {
return SetProcessGroupValue(pid, "MemSwappiness", swappiness);
}
bool setProcessGroupSoftLimit(uid_t, int pid, int64_t soft_limit_in_bytes) {
return SetProcessGroupValue(pid, "MemSoftLimit", soft_limit_in_bytes);
}
bool setProcessGroupLimit(uid_t, int pid, int64_t limit_in_bytes) {
return SetProcessGroupValue(pid, "MemLimit", limit_in_bytes);
}
bool getAttributePathForTask(const std::string& attr_name, int tid, std::string* path) {
return CgroupGetAttributePathForTask(attr_name, tid, path);
}
bool isProfileValidForProcess(const std::string& profile_name, int uid, int pid) {
const TaskProfile* tp = TaskProfiles::GetInstance().GetProfile(profile_name);
if (tp == nullptr) {
return false;
}
return tp->IsValidForProcess(uid, pid);
}
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