mm: memcg: drop obsolete cache line padding in struct mem_cgroup

After the grouping of the cgroup v1-related fields and the corresponding
reorganization of the struct mem_cgroup, the existing cache line padding
doesn't make much sense anymore.  Let's drop it for now and put back to
new places, if necessary.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Roman Gushchin <[email protected]>
Suggested-by: Shakeel Butt <[email protected]>
Acked-by: Shakeel Butt <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: rgushchin

include/linux/memcontrol.h

@@ -220,8 +220,6 @@ struct mem_cgroup {
 	/* handle for "memory.swap.events" */
 	struct cgroup_file swap_events_file;
 
-	CACHELINE_PADDING(_pad1_);
-
 	/* memory.stat */
 	struct memcg_vmstats	*vmstats;
 
@@ -305,8 +303,6 @@ struct mem_cgroup {
 	bool tcpmem_active;
 	int tcpmem_pressure;
 
-	CACHELINE_PADDING(_pad2_);
-
 	/*
 	 * set > 0 if pages under this cgroup are moving to other cgroup.
 	 */