mm: get rid of unnecessary overhead of trace_mm_page_alloc_extfrag()

In general, every tracepoint should be zero overhead if it is disabled.
However, trace_mm_page_alloc_extfrag() is one of exception.  It evaluate
"new_type == start_migratetype" even if tracepoint is disabled.

However, the code can be moved into tracepoint's TP_fast_assign() and
TP_fast_assign exist exactly such purpose.  This patch does it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index d0c6134..aece134 100644 (file)
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -267,14 +267,12 @@ DEFINE_EVENT_PRINT(mm_page, mm_page_pcpu_drain,
 TRACE_EVENT(mm_page_alloc_extfrag,
 
        TP_PROTO(struct page *page,
-                       int alloc_order, int fallback_order,
-                       int alloc_migratetype, int fallback_migratetype,
-                       int change_ownership),
+               int alloc_order, int fallback_order,
+               int alloc_migratetype, int fallback_migratetype, int new_migratetype),
 
        TP_ARGS(page,
                alloc_order, fallback_order,
-               alloc_migratetype, fallback_migratetype,
-               change_ownership),
+               alloc_migratetype, fallback_migratetype, new_migratetype),
 
        TP_STRUCT__entry(
                __field(        struct page *,  page                    )
@@ -291,7 +289,7 @@ 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;
+               __entry->change_ownership       = (new_migratetype == alloc_migratetype);
        ),
 
        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",

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5a98836..442f129 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1103,9 +1103,8 @@ __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, migratetype,
-                               new_type == start_migratetype);
+                       trace_mm_page_alloc_extfrag(page, order, current_order,
+                               start_migratetype, migratetype, new_type);
 
                        return page;
                }