mm/migrate: add MR_DAMON to migrate_reason

The current patch series introduces DAMON based migration across NUMA
nodes so it'd be better to have a new migrate_reason in trace events.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Honggyu Kim <[e-mail]>
Reviewed-by: SeongJae Park <[e-mail]>
Signed-off-by: SeongJae Park <[e-mail]>
Cc: Gregory Price <[e-mail]>
Cc: Hyeonggon Yoo <[e-mail]>
Cc: Hyeongtak Ji <[e-mail]>
Cc: Masami Hiramatsu (Google) <[e-mail]>
Cc: Mathieu Desnoyers <[e-mail]>
Cc: Rakie Kim <[e-mail]>
Cc: Steven Rostedt (Google) <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/migrate_mode.h

···
 	MR_CONTIG_RANGE,
 	MR_LONGTERM_PIN,
 	MR_DEMOTION,
+	MR_DAMON,
 	MR_TYPES
 };
 

include/trace/events/migrate.h

···
 	EM( MR_NUMA_MISPLACED,	"numa_misplaced")		\
 	EM( MR_CONTIG_RANGE,	"contig_range")			\
 	EM( MR_LONGTERM_PIN,	"longterm_pin")			\
-	EMe(MR_DEMOTION,	"demotion")
+	EM( MR_DEMOTION,	"demotion")			\
+	EMe(MR_DAMON,		"damon")
 
 /*
  * First define the enums in the above macros to be exported to userspace