ANDROID: GKI: add fields from per-process mm event tracking feature

mm_event feature exports mm_event_count function and adds new fields
in the task_struct. Fix ABI diffs by adding the necessary padding.

Bug: 80168800
Bug: 116825053
Bug: 153442668
Test: boot
Change-Id: I4e69c994f47402766481c58ab5ec2071180964b8
Signed-off-by: Minchan Kim <minchan@google.com>
(cherry picked from commit 04ff5ec537a5f9f546dcb32257d8fbc1f4d9ca2d)
Signed-off-by: Martin Liu <liumartin@google.com>
[surenb: cherry picked and trimmed the original patch to include only
necessary changes to resolve ABI diff for task_struct and
mm_event_count, changed enum mm_event_type to contain the final
members]

Bug: 149182139
Test: build and boot
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Iacdba61298ba15fc71b46e0323b4160f174300b7

include/linux/mm_event.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_EVENT_H
+#define _LINUX_MM_EVENT_H
+
+enum mm_event_type {
+	MM_MIN_FAULT = 0,
+	MM_MAJ_FAULT = 1,
+	MM_READ_IO = 2,
+	MM_COMPACTION = 3,
+	MM_RECLAIM = 4,
+	MM_SWP_FAULT = 5,
+	MM_KERN_ALLOC = 6,
+	MM_TYPE_NUM = 7,
+};
+
+struct mm_event_task {
+	unsigned int count;
+	unsigned int max_lat;
+	u64 accm_lat;
+} __attribute__ ((packed));
+
+#endif

include/linux/sched.h

@@ -26,6 +26,7 @@
 #include <linux/sched/prio.h>
 #include <linux/signal_types.h>
 #include <linux/mm_types_task.h>
+#include <linux/mm_event.h>
 #include <linux/task_io_accounting.h>
 #include <linux/rseq.h>
 
@@ -971,7 +972,10 @@ struct task_struct {
 	/* Deadlock detection and priority inheritance handling: */
 	struct rt_mutex_waiter		*pi_blocked_on;
 #endif
-
+#ifdef CONFIG_MM_EVENT_STAT
+	struct mm_event_task	mm_event[MM_TYPE_NUM];
+	unsigned long		next_period;
+#endif
 #ifdef CONFIG_DEBUG_MUTEXES
 	/* Mutex deadlock detection: */
 	struct mutex_waiter		*blocked_on;

mm/Kconfig

@@ -614,6 +614,22 @@ config ZSMALLOC_STAT
 	  information to userspace via debugfs.
 	  If unsure, say N.
 
+config MM_EVENT_STAT
+	bool "Track per-process MM event"
+	depends on MMU
+	help
+	  This option enables per-process mm event stat(e.g., fault, reclaim,
+	  compaction and so on ) with some interval(Default is 0.5sec).
+	  Admin can see the stat from trace file via debugfs(e.g.,
+	  /sys/kernel/debug/tracing/trace)
+
+	  It includes max/average memory allocation latency for the interval
+	  as well as event count so that admin can see what happens in VM side
+	  (how many each event happens and how much processes spent time for
+	  the MM event). If it's too large, that would be not good situation.
+
+	  System can dump the trace into bugreport when user allows the dump.
+
 config GENERIC_EARLY_IOREMAP
 	bool
 

mm/Makefile

@@ -28,6 +28,9 @@ mmu-$(CONFIG_MMU)	:= gup.o highmem.o memory.o mincore.o \
 			   rmap.o vmalloc.o
 
 
+ifdef CONFIG_MM_EVENT_STAT
+mmu-$(CONFIG_MMU)	+= mm_event.o
+endif
 ifdef CONFIG_CROSS_MEMORY_ATTACH
 mmu-$(CONFIG_MMU)	+= process_vm_access.o
 endif

mm/mm_event.c

@@ -0,0 +1,7 @@
+#include <linux/mm.h>
+#include <linux/mm_event.h>
+
+void mm_event_count(enum mm_event_type event, int count)
+{
+}
+EXPORT_SYMBOL_GPL(mm_event_count);