commit 304881205579d65819711d8fe733c31f100977fa
author Bart Van Assche <bvanassche@google.com> Wed Nov 15 09:11:20 2023 -0800
committer Bart Van Assche <bvanassche@google.com> Fri Nov 17 14:28:30 2023 -0800
tree 2e967ca804f8986de415f34be5e27c9a624e37c3
parent 72d8882153f4f18fe039d7c26302dd2708159bc2

Revert "libprocessgroup: Add a function to remove only empty process groups"

Revert this CL because it tests whether or not cgroup.procs files are
empty with the stat() system call and because the cgroup filesystem
always reports st_size == 0. Rename RemoveUidCgroups() into
RemoveEmptyUidCgroups().

Change-Id: I4de6f16c814c4b47d8d74c8045f0c1ee71975ac0
Signed-off-by: Bart Van Assche <bvanassche@google.com>

libprocessgroup/processgroup.cpp

diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index d352f0e..b4482d0 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -233,7 +233,7 @@
     return ret;
 }
 
-static bool RemoveUidCgroups(const std::string& uid_path, bool empty_only) {
+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) {
@@ -248,21 +248,6 @@
             }
 
             auto path = StringPrintf("%s/%s", uid_path.c_str(), dir->d_name);
-            if (empty_only) {
-                struct stat st;
-                auto procs_file = StringPrintf("%s/%s", path.c_str(),
-                                               PROCESSGROUP_CGROUP_PROCS_FILE);
-                if (stat(procs_file.c_str(), &st) == -1) {
-                    PLOG(ERROR) << "Failed to get stats for " << procs_file;
-                    continue;
-                }
-                if (st.st_size > 0) {
-                    // skip non-empty groups
-                    LOG(VERBOSE) << "Skipping non-empty group " << path;
-                    empty = false;
-                    continue;
-                }
-            }
             LOG(VERBOSE) << "Removing " << path;
             if (rmdir(path.c_str()) == -1) {
                 if (errno != EBUSY) {
@@ -275,7 +260,9 @@
     return empty;
 }
 
-static void removeAllProcessGroupsInternal(bool empty_only) {
+void removeAllEmptyProcessGroups() {
+    LOG(VERBOSE) << "removeAllEmptyProcessGroups()";
+
     std::vector<std::string> cgroups;
     std::string path, memcg_apps_path;
 
@@ -302,7 +289,7 @@
                 }
 
                 auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name);
-                if (!RemoveUidCgroups(path, empty_only)) {
+                if (!RemoveEmptyUidCgroups(path)) {
                     LOG(VERBOSE) << "Skip removing " << path;
                     continue;
                 }
@@ -315,16 +302,6 @@
     }
 }
 
-void removeAllProcessGroups() {
-    LOG(VERBOSE) << "removeAllProcessGroups()";
-    removeAllProcessGroupsInternal(false);
-}
-
-void removeAllEmptyProcessGroups() {
-    LOG(VERBOSE) << "removeAllEmptyProcessGroups()";
-    removeAllProcessGroupsInternal(true);
-}
-
 /**
  * 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