commit 4f7cc8c3455b2a28984e2682c1b8075cb57d67fe
author Suren Baghdasaryan <surenb@google.com> Thu Mar 02 14:12:49 2023 -0800
committer Suren Baghdasaryan <surenb@google.com> Fri Mar 03 00:11:13 2023 +0000
tree ddda201cade53ede07258f4a209f93811abbed2f
parent 8dab2ef586bb9d5bd1b1025a224be9eb6188e3f8

libprocessgroup: fix boot time performance regression

The way processes are accounted in DoKillProcessGroupOnce has been
changed recently, which affects retries in KillProcessGroup. More specifically, initialPid was not counted before and would not
cause a retry with 5ms sleep.
Restore previous behavior to avoid boot time regressions.

Bug: 271198843
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Ibc1bdd855898688a4a03806671e6ac31570aedf9

libprocessgroup/processgroup.cpp

diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 384a8f0..38f19ff 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -372,6 +372,7 @@
     std::set<pid_t> pgids;
     pgids.emplace(initialPid);
     std::set<pid_t> pids;
+    int processes = 0;
 
     std::unique_ptr<FILE, decltype(&fclose)> fd(nullptr, fclose);
 
@@ -390,6 +391,7 @@
         pid_t pid;
         bool file_is_empty = true;
         while (fscanf(fd.get(), "%d\n", &pid) == 1 && pid >= 0) {
+            processes++;
             file_is_empty = false;
             if (pid == 0) {
                 // Should never happen...  but if it does, trying to kill this
@@ -419,15 +421,12 @@
         }
     }
 
-    int processes = 0;
     // 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) == 0) {
-            processes++;
-        } else if (errno != ESRCH) {
+        if (kill(-pgid, signal) == -1 && errno != ESRCH) {
             PLOG(WARNING) << "kill(" << -pgid << ", " << signal << ") failed";
         }
     }
@@ -437,9 +436,7 @@
         LOG(VERBOSE) << "Killing pid " << pid << " in uid " << uid << " as part of process cgroup "
                      << initialPid;
 
-        if (kill(pid, signal) == 0) {
-            processes++;
-        } else if (errno != ESRCH) {
+        if (kill(pid, signal) == -1 && errno != ESRCH) {
             PLOG(WARNING) << "kill(" << pid << ", " << signal << ") failed";
         }
     }