libprocessgroup: Remove max_processes from KillProcessGroup API
The max_processes calculation is incorrect for KillProcessGroup because
the set of processes in cgroup.procs can differ between the multiple
reads in the implementation. Luckily the exact value isn't very
important because it's just logged. Remove max_processes from the API
and remove the warning about the new behavior in Android 11.
Note that we still always LOG(INFO) that any cgroup is being killed.
Bug: 301871933
Change-Id: I8e449f5089d4a48dbc1797b6d979539e87026f43
diff --git a/libprocessgroup/include/processgroup/processgroup.h b/libprocessgroup/include/processgroup/processgroup.h
index dbaeb93..5c43224 100644
--- a/libprocessgroup/include/processgroup/processgroup.h
+++ b/libprocessgroup/include/processgroup/processgroup.h
@@ -67,14 +67,11 @@
// Return 0 and removes the cgroup if there are no longer any processes in it.
// Returns -1 in the case of an error occurring or if there are processes still running
// even after retrying for up to 200ms.
-// If max_processes is not nullptr, it returns the maximum number of processes seen in the cgroup
-// during the killing process. Note that this can be 0 if all processes from the process group have
-// already been terminated.
-int killProcessGroup(uid_t uid, int initialPid, int signal, int* max_processes = nullptr);
+int killProcessGroup(uid_t uid, int initialPid, int signal);
// Returns the same as killProcessGroup(), however it does not retry, which means
// that it only returns 0 in the case that the cgroup exists and it contains no processes.
-int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_processes = nullptr);
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal);
// Sends the provided signal to all members of a process group, but does not wait for processes to
// exit, or for the cgroup to be removed. Callers should also ensure that killProcessGroup is called
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index cc2565f..3fa43f8 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -455,8 +455,7 @@
return (!fd || feof(fd.get())) ? processes : -1;
}
-static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries,
- int* max_processes) {
+static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries) {
CHECK_GE(uid, 0);
CHECK_GT(initialPid, 0);
@@ -468,16 +467,9 @@
std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
- if (max_processes != nullptr) {
- *max_processes = 0;
- }
-
int retry = retries;
int processes;
while ((processes = DoKillProcessGroupOnce(cgroup, uid, initialPid, signal)) > 0) {
- if (max_processes != nullptr && processes > *max_processes) {
- *max_processes = processes;
- }
LOG(VERBOSE) << "Killed " << processes << " processes for processgroup " << initialPid;
if (!CgroupsAvailable()) {
// makes no sense to retry, because there are no cgroup_procs file
@@ -540,12 +532,12 @@
}
}
-int killProcessGroup(uid_t uid, int initialPid, int signal, int* max_processes) {
- return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/, max_processes);
+int killProcessGroup(uid_t uid, int initialPid, int signal) {
+ return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/);
}
-int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_processes) {
- return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/, max_processes);
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal) {
+ return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/);
}
int sendSignalToProcessGroup(uid_t uid, int initialPid, int signal) {