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page_pool: extend tracepoint to also include the page PFN
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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@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jesper Dangaard Brouer authored and David S. Miller committed Nov 19, 2019
1 parent 7c9e694 commit 832ccf6
Showing 1 changed file with 9 additions and 4 deletions.
13 changes: 9 additions & 4 deletions include/trace/events/page_pool.h
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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,
Expand All @@ -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 */
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