Merge "Reuse mem cgroups for tracking forked PIDs."
diff --git a/libprocessgroup/Android.mk b/libprocessgroup/Android.mk
index ee6ba58..1885fa5 100644
--- a/libprocessgroup/Android.mk
+++ b/libprocessgroup/Android.mk
@@ -7,14 +7,4 @@
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
 LOCAL_CFLAGS := -Wall -Werror
-LOCAL_REQUIRED_MODULE := processgroup_cleanup
 include $(BUILD_SHARED_LIBRARY)
-
-include $(CLEAR_VARS)
-LOCAL_SRC_FILES := cleanup.cpp
-LOCAL_MODULE := processgroup_cleanup
-LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
-LOCAL_CFLAGS := -Wall -Werror
-LOCAL_FORCE_STATIC_EXECUTABLE := true
-LOCAL_STATIC_LIBRARIES := libc libcutils
-include $(BUILD_EXECUTABLE)
diff --git a/libprocessgroup/cleanup.cpp b/libprocessgroup/cleanup.cpp
deleted file mode 100644
index cca8dc4..0000000
--- a/libprocessgroup/cleanup.cpp
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- *  Copyright 2014 Google, Inc
- *
- *  Licensed under the Apache License, Version 2.0 (the "License");
- *  you may not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- */
-#include <string.h>
-#include <unistd.h>
-#include <sys/syslimits.h>
-
-#include "processgroup_priv.h"
-
-int main(int argc, char **argv)
-{
-    char buf[PATH_MAX];
-    if (argc != 2)
-        return -1;
-
-    memcpy(buf, PROCESSGROUP_CGROUP_PATH, sizeof(PROCESSGROUP_CGROUP_PATH));
-    strlcat(buf, argv[1], sizeof(buf));
-    return rmdir(buf);
-}
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index ad0500d..f160ac1 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <mutex>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -35,7 +36,26 @@
 #include <utils/SystemClock.h>
 
 #include <processgroup/processgroup.h>
-#include "processgroup_priv.h"
+
+#define MEM_CGROUP_PATH "/dev/memcg/apps"
+#define ACCT_CGROUP_PATH "/acct"
+
+#define PROCESSGROUP_UID_PREFIX "uid_"
+#define PROCESSGROUP_PID_PREFIX "pid_"
+#define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs"
+#define PROCESSGROUP_MAX_UID_LEN 11
+#define PROCESSGROUP_MAX_PID_LEN 11
+#define PROCESSGROUP_MAX_PATH_LEN \
+        ((sizeof(MEM_CGROUP_PATH) > sizeof(ACCT_CGROUP_PATH) ? \
+          sizeof(MEM_CGROUP_PATH) : sizeof(ACCT_CGROUP_PATH)) + \
+         sizeof(PROCESSGROUP_UID_PREFIX) + 1 + \
+         PROCESSGROUP_MAX_UID_LEN + \
+         sizeof(PROCESSGROUP_PID_PREFIX) + 1 + \
+         PROCESSGROUP_MAX_PID_LEN + \
+         sizeof(PROCESSGROUP_CGROUP_PROCS_FILE) + \
+         1)
+
+std::once_flag init_path_flag;
 
 struct ctx {
     bool initialized;
@@ -45,10 +65,18 @@
     size_t buf_len;
 };
 
+static const char* getCgroupRootPath() {
+    static const char* cgroup_root_path = NULL;
+    std::call_once(init_path_flag, [&]() {
+            cgroup_root_path = access(MEM_CGROUP_PATH, W_OK) ? ACCT_CGROUP_PATH : MEM_CGROUP_PATH;
+            });
+    return cgroup_root_path;
+}
+
 static int convertUidToPath(char *path, size_t size, uid_t uid)
 {
     return snprintf(path, size, "%s/%s%d",
-            PROCESSGROUP_CGROUP_PATH,
+            getCgroupRootPath(),
             PROCESSGROUP_UID_PREFIX,
             uid);
 }
@@ -56,7 +84,7 @@
 static int convertUidPidToPath(char *path, size_t size, uid_t uid, int pid)
 {
     return snprintf(path, size, "%s/%s%d/%s%d",
-            PROCESSGROUP_CGROUP_PATH,
+            getCgroupRootPath(),
             PROCESSGROUP_UID_PREFIX,
             uid,
             PROCESSGROUP_PID_PREFIX,
@@ -188,9 +216,10 @@
 void removeAllProcessGroups()
 {
     SLOGV("removeAllProcessGroups()");
-    DIR *root = opendir(PROCESSGROUP_CGROUP_PATH);
+    const char *cgroup_root_path = getCgroupRootPath();
+    DIR *root = opendir(cgroup_root_path);
     if (root == NULL) {
-        SLOGE("failed to open %s: %s", PROCESSGROUP_CGROUP_PATH, strerror(errno));
+        SLOGE("failed to open %s: %s", cgroup_root_path, strerror(errno));
     } else {
         struct dirent cur;
         struct dirent *dir;
@@ -204,7 +233,7 @@
                 continue;
             }
 
-            snprintf(path, sizeof(path), "%s/%s", PROCESSGROUP_CGROUP_PATH, dir->d_name);
+            snprintf(path, sizeof(path), "%s/%s", cgroup_root_path, dir->d_name);
             removeUidProcessGroups(path);
             SLOGV("removing %s\n", path);
             rmdir(path);
diff --git a/libprocessgroup/processgroup_priv.h b/libprocessgroup/processgroup_priv.h
deleted file mode 100644
index 1895bf9..0000000
--- a/libprocessgroup/processgroup_priv.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
- *  Copyright 2014 Google, Inc
- *
- *  Licensed under the Apache License, Version 2.0 (the "License");
- *  you may not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- */
-
-#ifndef _PROCESSGROUP_PRIV_H_
-#define _PROCESSGROUP_PRIV_H_
-
-#define PROCESSGROUP_CGROUP_PATH "/acct"
-#define PROCESSGROUP_UID_PREFIX "uid_"
-#define PROCESSGROUP_PID_PREFIX "pid_"
-#define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs"
-#define PROCESSGROUP_MAX_UID_LEN 11
-#define PROCESSGROUP_MAX_PID_LEN 11
-#define PROCESSGROUP_MAX_PATH_LEN \
-        (sizeof(PROCESSGROUP_CGROUP_PATH) + \
-         sizeof(PROCESSGROUP_UID_PREFIX) + 1 + \
-         PROCESSGROUP_MAX_UID_LEN + \
-         sizeof(PROCESSGROUP_PID_PREFIX) + 1 + \
-         PROCESSGROUP_MAX_PID_LEN + \
-         sizeof(PROCESSGROUP_CGROUP_PROCS_FILE) + \
-         1)
-
-#endif
diff --git a/rootdir/init.rc b/rootdir/init.rc
index ee216fa..21ecb5a 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -43,19 +43,6 @@
     mount cgroup none /acct cpuacct
     mkdir /acct/uid
 
-    # Create cgroup mount point for memory
-    mount tmpfs none /sys/fs/cgroup mode=0750,uid=0,gid=1000
-    mkdir /sys/fs/cgroup/memory 0750 root system
-    mount cgroup none /sys/fs/cgroup/memory memory
-    write /sys/fs/cgroup/memory/memory.move_charge_at_immigrate 1
-    chown root system /sys/fs/cgroup/memory/tasks
-    chmod 0660 /sys/fs/cgroup/memory/tasks
-    mkdir /sys/fs/cgroup/memory/sw 0750 root system
-    write /sys/fs/cgroup/memory/sw/memory.swappiness 100
-    write /sys/fs/cgroup/memory/sw/memory.move_charge_at_immigrate 1
-    chown root system /sys/fs/cgroup/memory/sw/tasks
-    chmod 0660 /sys/fs/cgroup/memory/sw/tasks
-
     # Create energy-aware scheduler tuning nodes
     mkdir /sys/fs/cgroup/stune
     mount cgroup none /sys/fs/cgroup/stune schedtune
@@ -95,9 +82,11 @@
     symlink /storage/self/primary /sdcard
     symlink /mnt/user/0/primary /mnt/runtime/default/self/primary
 
-    # memory control cgroup
+    # root memory control cgroup, used by lmkd
     mkdir /dev/memcg 0700 root system
     mount cgroup none /dev/memcg memory
+    # app mem cgroups, used by activity manager and lmkd
+    mkdir /dev/memcg/apps/ 0755 system system
 
     write /proc/sys/kernel/panic_on_oops 1
     write /proc/sys/kernel/hung_task_timeout_secs 0