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