mm: Add reliable_nr_page for accounting reliable memory

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

-------------------------------------------------

Adding an variable in mm_struct for accouting the amount of reliable memory
allocated by the reliable user tasks.

Use KABI_RESERVE(3) in mm_struct to avoid any kapi changes.
Signed-off-by: NPeng Wu <wupeng58@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/linux/mm_types.h

@@ -529,7 +529,12 @@ struct mm_struct {
 	KABI_RESERVE(2)
 #endif
 
+#if IS_ENABLED(CONFIG_MEMORY_RELIABLE) && !defined(__GENKSYMS__)
+	atomic_long_t reliable_nr_page; /* total used reliable pages */
+#else
 	KABI_RESERVE(3)
+#endif
+
 	KABI_RESERVE(4)
 	KABI_RESERVE(5)
 	KABI_RESERVE(6)