From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 53BF76B005D for ; Thu, 6 Aug 2009 12:07:11 -0400 (EDT) From: Mel Gorman Subject: [PATCH 2/6] tracing, page-allocator: Add trace events for anti-fragmentation falling back to other migratetypes Date: Thu, 6 Aug 2009 17:07:03 +0100 Message-Id: <1249574827-18745-3-git-send-email-mel@csn.ul.ie> In-Reply-To: <1249574827-18745-1-git-send-email-mel@csn.ul.ie> References: <1249574827-18745-1-git-send-email-mel@csn.ul.ie> Sender: owner-linux-mm@kvack.org To: Larry Woodman , Andrew Morton Cc: riel@redhat.com, Ingo Molnar , Peter Zijlstra , LKML , linux-mm@kvack.org, Mel Gorman List-ID: Fragmentation avoidance depends on being able to use free pages from lists of the appropriate migrate type. In the event this is not possible, __rmqueue_fallback() selects a different list and in some circumstances change the migratetype of the pageblock. Simplistically, the more times this event occurs, the more likely that fragmentation will be a problem later for hugepage allocation at least but there are other considerations such as the order of page being split to satisfy the allocation. This patch adds a trace event for __rmqueue_fallback() that reports what page is being used for the fallback, the orders of relevant pages, the desired migratetype and the migratetype of the lists being used, whether the pageblock changed type and whether this event is important with respect to fragmentation avoidance or not. This information can be used to help analyse fragmentation avoidance and help decide whether min_free_kbytes should be increased or not. Signed-off-by: Mel Gorman Acked-by: Rik van Riel --- include/trace/events/kmem.h | 44 +++++++++++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 6 +++++ 2 files changed, 50 insertions(+), 0 deletions(-) diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h index 8ab0f98..4aed74b 100644 --- a/include/trace/events/kmem.h +++ b/include/trace/events/kmem.h @@ -302,6 +302,50 @@ TRACE_EVENT(mm_page_alloc, show_gfp_flags(__entry->gfp_flags)) ); +TRACE_EVENT(mm_page_alloc_extfrag, + + TP_PROTO(struct page *page, + int alloc_order, int fallback_order, + int alloc_migratetype, int fallback_migratetype, + int fragmenting, int change_ownership), + + TP_ARGS(page, + alloc_order, fallback_order, + alloc_migratetype, fallback_migratetype, + fragmenting, change_ownership), + + TP_STRUCT__entry( + __field( struct page *, page ) + __field( int, alloc_order ) + __field( int, fallback_order ) + __field( int, alloc_migratetype ) + __field( int, fallback_migratetype ) + __field( int, fragmenting ) + __field( int, change_ownership ) + ), + + TP_fast_assign( + __entry->page = page; + __entry->alloc_order = alloc_order; + __entry->fallback_order = fallback_order; + __entry->alloc_migratetype = alloc_migratetype; + __entry->fallback_migratetype = fallback_migratetype; + __entry->fragmenting = fragmenting; + __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", + __entry->page, + page_to_pfn(__entry->page), + __entry->alloc_order, + __entry->fallback_order, + pageblock_order, + __entry->alloc_migratetype, + __entry->fallback_migratetype, + __entry->fragmenting, + __entry->change_ownership) +); + #endif /* _TRACE_KMEM_H */ /* This part must be outside protection */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f3f6039..0b2a6d9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -839,6 +839,12 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) start_migratetype); expand(zone, page, order, current_order, area, migratetype); + + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, migratetype, + current_order < pageblock_order, + migratetype == start_migratetype); + return page; } } -- 1.6.3.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org