[tip:perf/urgent] tracing, mm: Record pfn instead of pointer to struct page

[tip-bot for Namhyung Kim <tipbot@zytor.com>]

Commit-ID:  9fdd8a875c6f3b02af48d5fa426206ca009b2b06
Gitweb:     http://git.kernel.org/tip/9fdd8a875c6f3b02af48d5fa426206ca009b2b06
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Mon, 6 Apr 2015 14:36:09 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 13 Apr 2015 11:44:52 -0300

tracing, mm: Record pfn instead of pointer to struct page

The struct page is opaque for userspace tools, so it'd be better to save
pfn in order to identify page frames.

The textual output of $debugfs/tracing/trace file remains unchanged and
only raw (binary) data format is changed - but thanks to libtraceevent,
userspace tools which deal with the raw data (like perf and trace-cmd)
can parse the format easily.  So impact on the userspace will also be
minimal.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Based-on-patch-by: Joonsoo Kim <js1304@gmail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1428298576-9785-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 include/trace/events/filemap.h |  8 ++++----
 include/trace/events/kmem.h    | 42 +++++++++++++++++++++---------------------
 include/trace/events/vmscan.h  |  8 ++++----
 3 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/include/trace/events/filemap.h b/include/trace/events/filemap.h
index 0421f49..42febb6 100644
--- a/include/trace/events/filemap.h
+++ b/include/trace/events/filemap.h
@@ -18,14 +18,14 @@ DECLARE_EVENT_CLASS(mm_filemap_op_page_cache,
 	TP_ARGS(page),
 
 	TP_STRUCT__entry(
-		__field(struct page *, page)
+		__field(unsigned long, pfn)
 		__field(unsigned long, i_ino)
 		__field(unsigned long, index)
 		__field(dev_t, s_dev)
 	),
 
 	TP_fast_assign(
-		__entry->page = page;
+		__entry->pfn = page_to_pfn(page);
 		__entry->i_ino = page->mapping->host->i_ino;
 		__entry->index = page->index;
 		if (page->mapping->host->i_sb)
@@ -37,8 +37,8 @@ DECLARE_EVENT_CLASS(mm_filemap_op_page_cache,
 	TP_printk("dev %d:%d ino %lx page=%p pfn=%lu ofs=%lu",
 		MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
 		__entry->i_ino,
-		__entry->page,
-		page_to_pfn(__entry->page),
+		pfn_to_page(__entry->pfn),
+		__entry->pfn,
 		__entry->index << PAGE_SHIFT)
 );
 
diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 4ad10ba..81ea598 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -154,18 +154,18 @@ TRACE_EVENT(mm_page_free,
 	TP_ARGS(page, order),
 
 	TP_STRUCT__entry(
-		__field(	struct page *,	page		)
+		__field(	unsigned long,	pfn		)
 		__field(	unsigned int,	order		)
 	),
 
 	TP_fast_assign(
-		__entry->page		= page;
+		__entry->pfn		= page_to_pfn(page);
 		__entry->order		= order;
 	),
 
 	TP_printk("page=%p pfn=%lu order=%d",
-			__entry->page,
-			page_to_pfn(__entry->page),
+			pfn_to_page(__entry->pfn),
+			__entry->pfn,
 			__entry->order)
 );
 
@@ -176,18 +176,18 @@ TRACE_EVENT(mm_page_free_batched,
 	TP_ARGS(page, cold),
 
 	TP_STRUCT__entry(
-		__field(	struct page *,	page		)
+		__field(	unsigned long,	pfn		)
 		__field(	int,		cold		)
 	),
 
 	TP_fast_assign(
-		__entry->page		= page;
+		__entry->pfn		= page_to_pfn(page);
 		__entry->cold		= cold;
 	),
 
 	TP_printk("page=%p pfn=%lu order=0 cold=%d",
-			__entry->page,
-			page_to_pfn(__entry->page),
+			pfn_to_page(__entry->pfn),
+			__entry->pfn,
 			__entry->cold)
 );
 
@@ -199,22 +199,22 @@ TRACE_EVENT(mm_page_alloc,
 	TP_ARGS(page, order, gfp_flags, migratetype),
 
 	TP_STRUCT__entry(
-		__field(	struct page *,	page		)
+		__field(	unsigned long,	pfn		)
 		__field(	unsigned int,	order		)
 		__field(	gfp_t,		gfp_flags	)
 		__field(	int,		migratetype	)
 	),
 
 	TP_fast_assign(
-		__entry->page		= page;
+		__entry->pfn		= page ? page_to_pfn(page) : -1UL;
 		__entry->order		= order;
 		__entry->gfp_flags	= gfp_flags;
 		__entry->migratetype	= migratetype;
 	),
 
 	TP_printk("page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s",
-		__entry->page,
-		__entry->page ? page_to_pfn(__entry->page) : 0,
+		__entry->pfn != -1UL ? pfn_to_page(__entry->pfn) : NULL,
+		__entry->pfn != -1UL ? __entry->pfn : 0,
 		__entry->order,
 		__entry->migratetype,
 		show_gfp_flags(__entry->gfp_flags))
@@ -227,20 +227,20 @@ DECLARE_EVENT_CLASS(mm_page,
 	TP_ARGS(page, order, migratetype),
 
 	TP_STRUCT__entry(
-		__field(	struct page *,	page		)
+		__field(	unsigned long,	pfn		)
 		__field(	unsigned int,	order		)
 		__field(	int,		migratetype	)
 	),
 
 	TP_fast_assign(
-		__entry->page		= page;
+		__entry->pfn		= page ? page_to_pfn(page) : -1UL;
 		__entry->order		= order;
 		__entry->migratetype	= migratetype;
 	),
 
 	TP_printk("page=%p pfn=%lu order=%u migratetype=%d percpu_refill=%d",
-		__entry->page,
-		__entry->page ? page_to_pfn(__entry->page) : 0,
+		__entry->pfn != -1UL ? pfn_to_page(__entry->pfn) : NULL,
+		__entry->pfn != -1UL ? __entry->pfn : 0,
 		__entry->order,
 		__entry->migratetype,
 		__entry->order == 0)
@@ -260,7 +260,7 @@ DEFINE_EVENT_PRINT(mm_page, mm_page_pcpu_drain,
 	TP_ARGS(page, order, migratetype),
 
 	TP_printk("page=%p pfn=%lu order=%d migratetype=%d",
-		__entry->page, page_to_pfn(__entry->page),
+		pfn_to_page(__entry->pfn), __entry->pfn,
 		__entry->order, __entry->migratetype)
 );
 
@@ -275,7 +275,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
 		alloc_migratetype, fallback_migratetype),
 
 	TP_STRUCT__entry(
-		__field(	struct page *,	page			)
+		__field(	unsigned long,	pfn			)
 		__field(	int,		alloc_order		)
 		__field(	int,		fallback_order		)
 		__field(	int,		alloc_migratetype	)
@@ -284,7 +284,7 @@ TRACE_EVENT(mm_page_alloc_extfrag,
 	),
 
 	TP_fast_assign(
-		__entry->page			= page;
+		__entry->pfn			= page_to_pfn(page);
 		__entry->alloc_order		= alloc_order;
 		__entry->fallback_order		= fallback_order;
 		__entry->alloc_migratetype	= alloc_migratetype;
@@ -294,8 +294,8 @@ TRACE_EVENT(mm_page_alloc_extfrag,
 	),
 
 	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),
+		pfn_to_page(__entry->pfn),
+		__entry->pfn,
 		__entry->alloc_order,
 		__entry->fallback_order,
 		pageblock_order,
diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index 69590b6..f66476b 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -336,18 +336,18 @@ TRACE_EVENT(mm_vmscan_writepage,
 	TP_ARGS(page, reclaim_flags),
 
 	TP_STRUCT__entry(
-		__field(struct page *, page)
+		__field(unsigned long, pfn)
 		__field(int, reclaim_flags)
 	),
 
 	TP_fast_assign(
-		__entry->page = page;
+		__entry->pfn = page_to_pfn(page);
 		__entry->reclaim_flags = reclaim_flags;
 	),
 
 	TP_printk("page=%p pfn=%lu flags=%s",
-		__entry->page,
-		page_to_pfn(__entry->page),
+		pfn_to_page(__entry->pfn),
+		__entry->pfn,
 		show_reclaim_flags(__entry->reclaim_flags))
 );