[PATCH 2/9] tracing, mm: Record pfn instead of pointer to struct page

From: Namhyung Kim
Date: Mon Apr 06 2015 - 01:38:57 EST


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.

Based-on-patch-by: Joonsoo Kim <js1304@xxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
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 0421f49a20f7..42febb6bc1d5 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 4ad10baecd4d..81ea59812117 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 69590b6ffc09..f66476b96264 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))
);

--
2.3.2

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