ANDROID: psi: Add vendor hooks for PSI tracing

Add hooks to capture various per-zone memory stats when
a trigger threshold is hit.
In the stability Monkey4SystemLongTime test, the camera startup will
request a large amount of memory in a short period of time,
resulting in a temporary shortage of system memory. In addition,
other processes also need to continuously request memory.In this
case, it is easy for the system to have lmkd blocked and unable to
kill the process in time, resulting in OOM.

This hook can be used to detect when lmkd is in D state and the 
memory pressure meets the set conditions, then the kill process 
mechanism is triggered to avoid the occurrence of OOM. In the
previous test, 1/20 machines had a problem at 74.49 hours,but after
the modification, 48 machines were tested for 120 hours without
any problems.

Bug: 268290366
Change-Id: Ibe39263ddb05ffc3fa63b5225497a90c6480c8d7
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
Signed-off-by: xiaofeng <xiaofeng5@xiaomi.com>

drivers/android/vendor_hooks.c

@@ -53,6 +53,7 @@
 #include <trace/hooks/topology.h>
 #include <trace/hooks/thermal.h>
 #include <trace/hooks/rwsem.h>
+#include <trace/hooks/psi.h>
 #include <trace/hooks/bl_hib.h>
 #include <trace/hooks/futex.h>
 #include <trace/hooks/bug.h>
@@ -302,6 +303,8 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_try_to_freeze_todo);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_try_to_freeze_todo_unfrozen);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_die_kernel_fault);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_do_sp_pc_abort);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_psi_event);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_psi_group);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_dma_buf_stats_teardown);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_dpm_wait_start);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_dpm_wait_finish);

include/trace/hooks/psi.h

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM psi
+
+#define TRACE_INCLUDE_PATH trace/hooks
+
+#if !defined(_TRACE_HOOK_PSI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_PSI_H
+
+#include <trace/hooks/vendor_hooks.h>
+
+struct psi_trigger;
+struct psi_group;
+DECLARE_HOOK(android_vh_psi_event,
+	TP_PROTO(struct psi_trigger *t),
+	TP_ARGS(t));
+
+DECLARE_HOOK(android_vh_psi_group,
+	TP_PROTO(struct psi_group *group),
+	TP_ARGS(group));
+
+#endif /* _TRACE_HOOK_PSI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

kernel/sched/psi.c

@@ -136,6 +136,7 @@
  * cost-wise, yet way more sensitive and accurate than periodic
  * sampling of the aggregate task states would be.
  */
+#include <trace/hooks/psi.h>
 
 static int psi_bug __read_mostly;
 
@@ -487,6 +488,8 @@ static void update_triggers(struct psi_group *group, u64 now,
 		if (now < t->last_event_time + t->win.size)
 			continue;
 
+		trace_android_vh_psi_event(t);
+
 		/* Generate an event */
 		if (cmpxchg(&t->event, 0, 1) == 0) {
 			if (t->of)
@@ -498,6 +501,8 @@ static void update_triggers(struct psi_group *group, u64 now,
 		/* Reset threshold breach flag once event got generated */
 		t->pending_event = false;
 	}
+
+	trace_android_vh_psi_group(group);
 }
 
 static u64 update_averages(struct psi_group *group, u64 now)