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Commit 4c95712c authored by Bart Van Assche's avatar Bart Van Assche
Browse files

Use the proper memcg directory for the v2 hierarchy 



When using the v1 hierarchy per process memcg directories exist under
/dev/memcg/apps. When using the v2 hierarchy per process memcg
directories exist under /sys/fs/cgroup. Hence this patch that selects
the proper top-level directory depending on the memcg version.

Bug: 213617178
Test: Verified Android operation inside the Cuttlefish emulator.
Change-Id: I7373fb407cb6ad2b1181579691ff54886fd36c24
Signed-off-by: default avatarBart Van Assche <bvanassche@google.com>
parent 3e9eeb83

libprocessgroup/processgroup.cpp

+31 −11
Original line number Diff line number Diff line
@@ -69,6 +69,23 @@ bool CgroupGetControllerPath(const std::string& cgroup_name, std::string* path) 
    return true;

}



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);
@@ -199,13 +216,13 @@ void removeAllProcessGroups() { 
    LOG(VERBOSE) << "removeAllProcessGroups()";



    std::vector<std::string> cgroups;

    std::string path;

    std::string path, memcg_apps_path;



    if (CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &path)) {

        cgroups.push_back(path);

    }

    if (CgroupGetControllerPath("memory", &path)) {

        cgroups.push_back(path + "/apps");

    if (CgroupGetMemcgAppsPath(&memcg_apps_path) && memcg_apps_path != path) {

        cgroups.push_back(memcg_apps_path);

    }



    for (std::string cgroup_root_path : cgroups) {
@@ -411,10 +428,11 @@ static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries, 
        int err = RemoveProcessGroup(cgroup, uid, initialPid, retries);



        if (isMemoryCgroupSupported() && UsePerAppMemcg()) {

            std::string memory_path;

            CgroupGetControllerPath("memory", &memory_path);

            memory_path += "/apps";

            if (RemoveProcessGroup(memory_path.c_str(), uid, initialPid, retries)) return -1;

            std::string memcg_apps_path;

            if (CgroupGetMemcgAppsPath(&memcg_apps_path) &&

                RemoveProcessGroup(memcg_apps_path.c_str(), uid, initialPid, retries) < 0) {

                return -1;

            }

        }



        return err;
@@ -491,10 +509,12 @@ int createProcessGroup(uid_t uid, int initialPid, bool memControl) { 
        return -EINVAL;

    }



    if (isMemoryCgroupSupported() && UsePerAppMemcg()) {

        CgroupGetControllerPath("memory", &cgroup);

        cgroup += "/apps";

        int ret = createProcessGroupInternal(uid, initialPid, cgroup, false);

    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;

        }