The patch titled
tracing, page-allocator: add trace event for page traffic related to the buddy lists
has been added to the -mm tree. Its filename is
tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: tracing, page-allocator: add trace event for page traffic related to the buddy lists
From: Mel Gorman <mel@xxxxxxxxx>
The page allocation trace event reports that a page was successfully
allocated but it does not specify where it came from. When analysing
performance, it can be important to distinguish between pages coming from
the per-cpu allocator and pages coming from the buddy lists as the latter
requires the zone lock to the taken and more data structures to be
examined.
This patch adds a trace event for __rmqueue reporting when a page is being
allocated from the buddy lists. It distinguishes between being called to
refill the per-cpu lists or whether it is a high-order allocation.
Similarly, this patch adds an event to catch when the PCP lists are being
drained a little and pages are going back to the buddy lists.
This is trickier to draw conclusions from but high activity on those
events could explain why there were a large number of cache misses on a
page-allocator-intensive workload. The coalescing and splitting of
buddies involves a lot of writing of page metadata and cache line bounces
not to mention the acquisition of an interrupt-safe lock necessary to
enter this path.
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Larry Woodman <lwoodman@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Li Ming Chun <macli@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/trace/events/kmem.h | 51 ++++++++++++++++++++++++++++++++++
mm/page_alloc.c | 2 +
2 files changed, 53 insertions(+)
diff -puN include/trace/events/kmem.h~tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists include/trace/events/kmem.h
--- a/include/trace/events/kmem.h~tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists
+++ a/include/trace/events/kmem.h
@@ -299,6 +299,57 @@ TRACE_EVENT(mm_page_alloc,
show_gfp_flags(__entry->gfp_flags))
);
+TRACE_EVENT(mm_page_alloc_zone_locked,
+
+ TP_PROTO(struct page *page, unsigned int order, int migratetype),
+
+ TP_ARGS(page, order, migratetype),
+
+ TP_STRUCT__entry(
+ __field( struct page *, page )
+ __field( unsigned int, order )
+ __field( int, migratetype )
+ ),
+
+ TP_fast_assign(
+ __entry->page = page;
+ __entry->order = order;
+ __entry->migratetype = migratetype;
+ ),
+
+ TP_printk("page=%p pfn=%lu order=%u migratetype=%d percpu_refill=%d",
+ __entry->page,
+ page_to_pfn(__entry->page),
+ __entry->order,
+ __entry->migratetype,
+ __entry->order == 0)
+);
+
+TRACE_EVENT(mm_page_pcpu_drain,
+
+ TP_PROTO(struct page *page, int order, int migratetype),
+
+ TP_ARGS(page, order, migratetype),
+
+ TP_STRUCT__entry(
+ __field( struct page *, page )
+ __field( int, order )
+ __field( int, migratetype )
+ ),
+
+ TP_fast_assign(
+ __entry->page = page;
+ __entry->order = order;
+ __entry->migratetype = migratetype;
+ ),
+
+ TP_printk("page=%p pfn=%lu order=%d migratetype=%d",
+ __entry->page,
+ page_to_pfn(__entry->page),
+ __entry->order,
+ __entry->migratetype)
+);
+
TRACE_EVENT(mm_page_alloc_extfrag,
TP_PROTO(struct page *page,
diff -puN mm/page_alloc.c~tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists mm/page_alloc.c
--- a/mm/page_alloc.c~tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists
+++ a/mm/page_alloc.c
@@ -546,6 +546,7 @@ static void free_pages_bulk(struct zone
page = list_entry(list->prev, struct page, lru);
/* have to delete it as __free_one_page list manipulates */
list_del(&page->lru);
+ trace_mm_page_pcpu_drain(page, order, page_private(page));
__free_one_page(page, zone, order, page_private(page));
}
spin_unlock(&zone->lock);
@@ -911,6 +912,7 @@ retry_reserve:
}
}
+ trace_mm_page_alloc_zone_locked(page, order, migratetype);
return page;
}
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
memory-hotplug-update-zone-pcp-at-memory-online.patch
memory-hotplug-update-zone-pcp-at-memory-online-fix.patch
memory-hotplug-exclude-isolated-page-from-pco-page-alloc.patch
memory-hotplug-make-pages-from-movable-zone-always-isolatable.patch
memory-hotplug-alloc-page-from-other-node-in-memory-online.patch
memory-hotplug-migrate-swap-cache-page.patch
hugetlb-balance-freeing-of-huge-pages-across-nodes.patch
hugetlb-use-free_pool_huge_page-to-return-unused-surplus-pages.patch
hugetlb-use-free_pool_huge_page-to-return-unused-surplus-pages-fix.patch
hugetlb-clean-up-and-update-huge-pages-documentation.patch
hugetlb-restore-interleaving-of-bootmem-huge-pages.patch
mm-clean-up-page_remove_rmap.patch
mm-update-alloc_flags-after-oom-killer-has-been-called.patch
vmscan-dont-attempt-to-reclaim-anon-page-in-lumpy-reclaim-when-no-swap-space-is-avilable.patch
vmscan-move-clearpageactive-from-move_active_pages-to-shrink_active_list.patch
vmscan-kill-unnecessary-page-flag-test.patch
vmscan-kill-unnecessary-prefetch.patch
mm-perform-non-atomic-test-clear-of-pg_mlocked-on-free.patch
mm-warn-once-when-a-page-is-freed-with-pg_mlocked-set.patch
page-allocator-change-migratetype-for-all-pageblocks-within-a-high-order-page-during-__rmqueue_fallback.patch
page-allocator-remove-dead-function-free_cold_page.patch
tracing-page-allocator-add-trace-events-for-page-allocation-and-page-freeing.patch
tracing-page-allocator-add-trace-events-for-anti-fragmentation-falling-back-to-other-migratetypes.patch
tracing-page-allocator-add-trace-event-for-page-traffic-related-to-the-buddy-lists.patch
tracing-page-allocator-add-a-postprocessing-script-for-page-allocator-related-ftrace-events.patch
tracing-documentation-add-a-document-describing-how-to-do-some-performance-analysis-with-tracepoints.patch
tracing-documentation-add-a-document-on-the-kmem-tracepoints.patch
add-debugging-aid-for-memory-initialisation-problems.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
