diff --git a/libprocessgroup/include/processgroup/processgroup.h b/libprocessgroup/include/processgroup/processgroup.h
index 11bd8cc..47f6ff3 100644
--- a/libprocessgroup/include/processgroup/processgroup.h
+++ b/libprocessgroup/include/processgroup/processgroup.h
@@ -24,6 +24,8 @@
 
 int killProcessGroup(uid_t uid, int initialPid, int signal);
 
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal);
+
 int createProcessGroup(uid_t uid, int initialPid);
 
 void removeAllProcessGroups(void);
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index eb66727..1572cb3 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -252,8 +252,7 @@
     }
 }
 
-static int killProcessGroupOnce(uid_t uid, int initialPid, int signal)
-{
+static int doKillProcessGroupOnce(uid_t uid, int initialPid, int signal) {
     int processes = 0;
     struct ctx ctx;
     pid_t pid;
@@ -282,13 +281,11 @@
     return processes;
 }
 
-int killProcessGroup(uid_t uid, int initialPid, int signal)
-{
+static int killProcessGroup(uid_t uid, int initialPid, int signal, int retry) {
     std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
 
-    int retry = 40;
     int processes;
-    while ((processes = killProcessGroupOnce(uid, initialPid, signal)) > 0) {
+    while ((processes = doKillProcessGroupOnce(uid, initialPid, signal)) > 0) {
         LOG(VERBOSE) << "killed " << processes << " processes for processgroup " << initialPid;
         if (retry > 0) {
             std::this_thread::sleep_for(5ms);
@@ -313,6 +310,14 @@
     }
 }
 
+int killProcessGroup(uid_t uid, int initialPid, int signal) {
+    return killProcessGroup(uid, initialPid, signal, 40 /*maxRetry*/);
+}
+
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal) {
+    return killProcessGroup(uid, initialPid, signal, 0 /*maxRetry*/);
+}
+
 static bool mkdirAndChown(const char *path, mode_t mode, uid_t uid, gid_t gid)
 {
     if (mkdir(path, mode) == -1 && errno != EEXIST) {