mm/page_alloc.c: fix the value of fallback_migratetype in alloc_extfrag tracepoint()

In the current code, the value of fallback_migratetype that is printed
using the mm_page_alloc_extfrag tracepoint, is the value of the
migratetype *after* it has been set to the preferred migratetype (if the
ownership was changed).  Obviously that wouldn't have been the original
intent.  (We already have a separate 'change_ownership' field to tell
whether the ownership of the pageblock was changed from the
fallback_migratetype to the preferred type.)

The intent of the fallback_migratetype field is to show the migratetype
from which we borrowed pages in order to satisfy the allocation request.
So fix the code to print that value correctly.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 10 insertions, 5 deletions

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 6bc943ecb841..d0c613476620 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -268,11 +268,13 @@ TRACE_EVENT(mm_page_alloc_extfrag,
 
         TP_PROTO(struct page *page,
                         int alloc_order, int fallback_order,
-                        int alloc_migratetype, int fallback_migratetype),
+                        int alloc_migratetype, int fallback_migratetype,
+                        int change_ownership),
 
         TP_ARGS(page,
                 alloc_order, fallback_order,
-                alloc_migratetype, fallback_migratetype),
+                alloc_migratetype, fallback_migratetype,
+                change_ownership),
 
         TP_STRUCT__entry(
                 __field(        struct page *,  page                    )
@@ -280,6 +282,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
                 __field(        int,            fallback_order          )
                 __field(        int,            alloc_migratetype       )
                 __field(        int,            fallback_migratetype    )
+                __field(        int,            change_ownership        )
         ),
 
         TP_fast_assign(
@@ -288,6 +291,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
                 __entry->fallback_order         = fallback_order;
                 __entry->alloc_migratetype      = alloc_migratetype;
                 __entry->fallback_migratetype   = fallback_migratetype;
+                __entry->change_ownership       = change_ownership;
         ),
 
         TP_printk("page=%p pfn=%lu alloc_order=%d fallback_order=%d pageblock_order=%d alloc_migratetype=%d fallback_migratetype=%d fragmenting=%d change_ownership=%d",
@@ -299,7 +303,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
                 __entry->alloc_migratetype,
                 __entry->fallback_migratetype,
                 __entry->fallback_order < pageblock_order,
-                __entry->alloc_migratetype == __entry->fallback_migratetype)
+                __entry->change_ownership)
 );
 
 #endif /* _TRACE_KMEM_H */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b09ce5fe0cd2..2748fc6a9003 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1101,8 +1101,9 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
                                is_migrate_cma(migratetype)
                              ? migratetype : start_migratetype);
 
-                        trace_mm_page_alloc_extfrag(page, order, current_order,
-                                start_migratetype, new_type);
+                        trace_mm_page_alloc_extfrag(page, order,
+                                current_order, start_migratetype, migratetype,
+                                new_type == start_migratetype);
 
                         return page;
                 }