From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755449AbZHJPmA (ORCPT ); Mon, 10 Aug 2009 11:42:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755339AbZHJPl7 (ORCPT ); Mon, 10 Aug 2009 11:41:59 -0400 Received: from gir.skynet.ie ([193.1.99.77]:51380 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbZHJPl5 (ORCPT ); Mon, 10 Aug 2009 11:41:57 -0400 From: Mel Gorman To: Larry Woodman , Ingo Molnar , Andrew Morton Cc: riel@redhat.com, Peter Zijlstra , Li Ming Chun , LKML , linux-mm@kvack.org, Mel Gorman Subject: [PATCH 2/6] tracing, page-allocator: Add trace events for anti-fragmentation falling back to other migratetypes Date: Mon, 10 Aug 2009 16:41:51 +0100 Message-Id: <1249918915-16061-3-git-send-email-mel@csn.ul.ie> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1249918915-16061-1-git-send-email-mel@csn.ul.ie> References: <1249918915-16061-1-git-send-email-mel@csn.ul.ie> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 | 38 ++++++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 4 ++++ 2 files changed, 42 insertions(+), 0 deletions(-) diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h index 0d358a0..aae16ee 100644 --- a/include/trace/events/kmem.h +++ b/include/trace/events/kmem.h @@ -299,6 +299,44 @@ 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), + + TP_ARGS(page, + alloc_order, fallback_order, + alloc_migratetype, fallback_migratetype), + + TP_STRUCT__entry( + __field( struct page *, page ) + __field( int, alloc_order ) + __field( int, fallback_order ) + __field( int, alloc_migratetype ) + __field( int, fallback_migratetype ) + ), + + 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; + ), + + 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->fallback_order < pageblock_order, + __entry->alloc_migratetype == __entry->fallback_migratetype) +); + #endif /* _TRACE_KMEM_H */ /* This part must be outside protection */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 440c439..4c20bfa 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -839,6 +839,10 @@ __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); + return page; } } -- 1.6.3.3