From 89a247a6384bf98144ef5588e1cdedee2973c5a4 Mon Sep 17 00:00:00 2001
From: Bing Han <bing.han@transsion.com>
Date: Mon, 30 May 2022 14:54:16 +0800
Subject: [PATCH] ANDROID: vendor_hook: Add hook in __migration_entry_wait()

android_vh_waiting_for_page_migration: provide a vendor hook
to force not to reclaim the page under migration to a specified
swap location, until the migration is finished.

Bug: 234214858
Signed-off-by: Bing Han <bing.han@transsion.com>
Change-Id: Iceeae91cbd912d9c44d7eac25f1299bbff547388
---
 drivers/android/vendor_hooks.c | 1 +
 include/trace/hooks/mm.h       | 3 +++
 mm/migrate.c                   | 3 +++
 3 files changed, 7 insertions(+)

diff --git a/drivers/android/vendor_hooks.c b/drivers/android/vendor_hooks.c
index c0855cc0692e..c581527d0397 100644
--- a/drivers/android/vendor_hooks.c
+++ b/drivers/android/vendor_hooks.c
@@ -410,6 +410,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_tune_memcg_scan_type);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_handle_pte_fault_end);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_cow_user_page);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_swapin_add_anon_rmap);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_waiting_for_page_migration);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_page_isolated_for_reclaim);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_inactive_is_low);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_snapshot_refaults);
diff --git a/include/trace/hooks/mm.h b/include/trace/hooks/mm.h
index 3d4bcd79cd34..9433497b3c7c 100644
--- a/include/trace/hooks/mm.h
+++ b/include/trace/hooks/mm.h
@@ -158,6 +158,9 @@ DECLARE_HOOK(android_vh_cow_user_page,
 DECLARE_HOOK(android_vh_swapin_add_anon_rmap,
 	TP_PROTO(struct vm_fault *vmf, struct page *page),
 	TP_ARGS(vmf, page));
+DECLARE_HOOK(android_vh_waiting_for_page_migration,
+	TP_PROTO(struct page *page),
+	TP_ARGS(page));
 DECLARE_HOOK(android_vh_page_isolated_for_reclaim,
 	TP_PROTO(struct mm_struct *mm, struct page *page),
 	TP_ARGS(mm, page));
diff --git a/mm/migrate.c b/mm/migrate.c
index 26f8595de076..a3cf3d624694 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -54,6 +54,8 @@
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/migrate.h>
+#undef CREATE_TRACE_POINTS
+#include <trace/hooks/mm.h>
 
 #include "internal.h"
 
@@ -311,6 +313,7 @@ void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 	if (!get_page_unless_zero(page))
 		goto out;
 	pte_unmap_unlock(ptep, ptl);
+	trace_android_vh_waiting_for_page_migration(page);
 	put_and_wait_on_page_locked(page);
 	return;
 out: