netdev - [net-next v2 PATCH 3/3] page_pool: extend tracepoint to also include the page PFN

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Message-ID: <157390336816.4062.15284686673295583294.stgit@firesoul>
Date:   Sat, 16 Nov 2019 12:22:48 +0100
From:   Jesper Dangaard Brouer <brouer@...hat.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Toke Høiland-Jørgensen <toke@...hat.com>,
        netdev@...r.kernel.org,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Matteo Croce <mcroce@...hat.com>,
        Jonathan Lemon <jonathan.lemon@...il.com>,
        Lorenzo Bianconi <lorenzo@...nel.org>,
        Tariq Toukan <tariqt@...lanox.com>
Subject: [net-next v2 PATCH 3/3] page_pool: extend tracepoint to also
 include the page PFN

The MM tracepoint for page free (called kmem:mm_page_free) doesn't provide
the page pointer directly, instead it provides the PFN (Page Frame Number).
This is annoying when writing a page_pool leak detector in BPF.

This patch change page_pool tracepoints to also provide the PFN.
The page pointer is still provided to allow other kinds of
troubleshooting from BPF.

Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
---
 include/trace/events/page_pool.h |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/page_pool.h b/include/trace/events/page_pool.h
index ee7f1aca7839..2f2a10e8eb56 100644
--- a/include/trace/events/page_pool.h
+++ b/include/trace/events/page_pool.h
@@ -8,6 +8,7 @@
 #include <linux/types.h>
 #include <linux/tracepoint.h>
 
+#include <trace/events/mmflags.h>
 #include <net/page_pool.h>
 
 TRACE_EVENT(page_pool_release,
@@ -49,16 +50,18 @@ TRACE_EVENT(page_pool_state_release,
 		__field(const struct page_pool *,	pool)
 		__field(const struct page *,		page)
 		__field(u32,				release)
+		__field(unsigned long,			pfn)
 	),
 
 	TP_fast_assign(
 		__entry->pool		= pool;
 		__entry->page		= page;
 		__entry->release	= release;
+		__entry->pfn		= page_to_pfn(page);
 	),
 
-	TP_printk("page_pool=%p page=%p release=%u",
-		  __entry->pool, __entry->page, __entry->release)
+	TP_printk("page_pool=%p page=%p pfn=%lu release=%u",
+		  __entry->pool, __entry->page, __entry->pfn, __entry->release)
 );
 
 TRACE_EVENT(page_pool_state_hold,
@@ -72,16 +75,18 @@ TRACE_EVENT(page_pool_state_hold,
 		__field(const struct page_pool *,	pool)
 		__field(const struct page *,		page)
 		__field(u32,				hold)
+		__field(unsigned long,			pfn)
 	),
 
 	TP_fast_assign(
 		__entry->pool	= pool;
 		__entry->page	= page;
 		__entry->hold	= hold;
+		__entry->pfn	= page_to_pfn(page);
 	),
 
-	TP_printk("page_pool=%p page=%p hold=%u",
-		  __entry->pool, __entry->page, __entry->hold)
+	TP_printk("page_pool=%p page=%p pfn=%lu hold=%u",
+		  __entry->pool, __entry->page, __entry->pfn, __entry->hold)
 );
 
 #endif /* _TRACE_PAGE_POOL_H */