Some compaction tracepoints convert the integer return values to strings using
the compaction_status_string array. This works for in-kernel printing, but not
userspace trace printing of raw captured trace such as via trace-cmd report.

This patch converts the private array to appropriate tracepoint macros that
result in proper userspace support.

trace-cmd output before:
transhuge-stres-4235  [000]   453.149280: mm_compaction_finished: node=0
  zone=ffffffff81815d7a order=9 ret=

after:
transhuge-stres-4235  [000]   453.149280: mm_compaction_finished: node=0
  zone=ffffffff81815d7a order=9 ret=partial

Signed-off-by: Vlastimil Babka <vba...@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo....@lge.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Mel Gorman <mgor...@suse.de>
Cc: David Rientjes <rient...@google.com>
---
 include/trace/events/compaction.h | 33 +++++++++++++++++++++++++++++++--
 mm/compaction.c                   | 11 -----------
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/include/trace/events/compaction.h 
b/include/trace/events/compaction.h
index 9a6a3fe..1275a55 100644
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -9,6 +9,35 @@
 #include <linux/tracepoint.h>
 #include <trace/events/gfpflags.h>
 
+#define COMPACTION_STATUS                                      \
+       EM( COMPACT_DEFERRED,           "deferred")             \
+       EM( COMPACT_SKIPPED,            "skipped")              \
+       EM( COMPACT_CONTINUE,           "continue")             \
+       EM( COMPACT_PARTIAL,            "partial")              \
+       EM( COMPACT_COMPLETE,           "complete")             \
+       EM( COMPACT_NO_SUITABLE_PAGE,   "no_suitable_page")     \
+       EMe(COMPACT_NOT_SUITABLE_ZONE,  "not_suitable_zone")
+
+/*
+ * First define the enums in the above macros to be exported to userspace
+ * via TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)       TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)      TRACE_DEFINE_ENUM(a);
+
+COMPACTION_STATUS
+
+/*
+ * Now redefine the EM() and EMe() macros to map the enums to the strings
+ * that will be printed in the output.
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)       {a, b},
+#define EMe(a, b)      {a, b}
+
 DECLARE_EVENT_CLASS(mm_compaction_isolate_template,
 
        TP_PROTO(
@@ -161,7 +190,7 @@ TRACE_EVENT(mm_compaction_end,
                __entry->free_pfn,
                __entry->zone_end,
                __entry->sync ? "sync" : "async",
-               compaction_status_string[__entry->status])
+               __print_symbolic(__entry->status, COMPACTION_STATUS))
 );
 
 TRACE_EVENT(mm_compaction_try_to_compact_pages,
@@ -217,7 +246,7 @@ DECLARE_EVENT_CLASS(mm_compaction_suitable_template,
                __entry->nid,
                __entry->name,
                __entry->order,
-               compaction_status_string[__entry->ret])
+               __print_symbolic(__entry->ret, COMPACTION_STATUS))
 );
 
 DEFINE_EVENT(mm_compaction_suitable_template, mm_compaction_finished,
diff --git a/mm/compaction.c b/mm/compaction.c
index 018f08d..7d6ef6e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -35,17 +35,6 @@ static inline void count_compact_events(enum vm_event_item 
item, long delta)
 #endif
 
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
-#ifdef CONFIG_TRACEPOINTS
-static const char *const compaction_status_string[] = {
-       "deferred",
-       "skipped",
-       "continue",
-       "partial",
-       "complete",
-       "no_suitable_page",
-       "not_suitable_zone",
-};
-#endif
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/compaction.h>
-- 
2.5.0

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