kabi: reserve space for memcg related structures

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4GII8?from=project-issue
CVE: NA

--------

We reserve some fields beforehand for memcg related structures prone
to change, therefore, we can hot add/change features of memcg with this enhancement.

After reserving, normally cache does not matter as the reserved fields
are not accessed at all.

--------
Signed-off-by: NLu Jialin <lujialin4@huawei.com>
Reviewed-by: Nweiyang wang <wangweiyang2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/memcontrol.h

@@ -21,6 +21,7 @@
 #include <linux/vmstat.h>
 #include <linux/writeback.h>
 #include <linux/page-flags.h>
+#include <linux/kabi.h>
 
 struct mem_cgroup;
 struct obj_cgroup;
@@ -61,6 +62,7 @@ struct mem_cgroup_reclaim_cookie {
 struct mem_cgroup_id {
 	int id;
 	refcount_t ref;
+	KABI_RESERVE(1)
 };
 
 /*
@@ -87,6 +89,9 @@ struct memcg_vmstats_percpu {
 	/* Cgroup1: threshold notifications & softlimit tree updates */
 	unsigned long		nr_page_events;
 	unsigned long		targets[MEM_CGROUP_NTARGETS];
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
 };
 
 struct memcg_vmstats {
@@ -152,6 +157,12 @@ struct mem_cgroup_per_node {
 	bool			on_tree;
 	struct mem_cgroup	*memcg;		/* Back pointer, we cannot */
 						/* use container_of	   */
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
+	KABI_RESERVE(5)
 };
 
 struct mem_cgroup_threshold {
@@ -359,6 +370,15 @@ struct mem_cgroup {
 	struct deferred_split deferred_split_queue;
 #endif
 
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
+	KABI_RESERVE(5)
+	KABI_RESERVE(6)
+	KABI_RESERVE(7)
+	KABI_RESERVE(8)
+
 	struct mem_cgroup_per_node *nodeinfo[0];
 	/* WARNING: nodeinfo must be the last member here */
 };