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@xxxxxxxxxxxxxxxxxx>
---
include/trace/events/kmem.h | 10 +++++++---
mm/page_alloc.c | 5 +++--
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 6bc943e..d0c6134 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 d4b8198..b86d7e3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1100,8 +1100,9 @@ __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;
}
--
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