ANDROID: cgroup: Add vendor hook to the cgroup

Add a vendor hook after attaching a task to a cgroup to 
recognize the group_id for performance tuning

Bug: 181917687

Signed-off-by: Frankie Chang <frankie.chang@mediatek.com>
Change-Id: I603afa3d893dd575a7dcb97f83bd9eacb8315bab
(cherry picked from commit de089a37a3d248608a1d5855a4ae82ebad3ec2ab)

drivers/android/vendor_hooks.c

@@ -29,6 +29,7 @@
 #include <trace/hooks/preemptirq.h>
 #include <trace/hooks/ftrace_dump.h>
 #include <trace/hooks/ufshcd.h>
+#include <trace/hooks/cgroup.h>
 
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
@@ -114,3 +115,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_ufs_prepare_command);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_ufs_update_sysfs);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_ufs_send_command);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_ufs_compl_command);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_cgroup_set_task);

include/trace/hooks/cgroup.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cgroup
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH trace/hooks
+#if !defined(_TRACE_HOOK_CGROUP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_CGROUP_H
+#include <linux/tracepoint.h>
+#include <trace/hooks/vendor_hooks.h>
+
+struct task_struct;
+DECLARE_HOOK(android_vh_cgroup_set_task,
+	TP_PROTO(int ret, struct task_struct *task),
+	TP_ARGS(ret, task));
+#endif
+
+#include <trace/define_trace.h>

kernel/cgroup/cgroup-v1.c

@@ -17,6 +17,7 @@
 #include <linux/fs_parser.h>
 
 #include <trace/events/cgroup.h>
+#include <trace/hooks/cgroup.h>
 
 /*
  * pidlists linger the following amount before being destroyed.  The goal
@@ -518,6 +519,7 @@ static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of,
 		goto out_finish;
 
 	ret = cgroup_attach_task(cgrp, task, threadgroup);
+	trace_android_vh_cgroup_set_task(ret, task);
 
 out_finish:
 	cgroup_procs_write_finish(task, locked);