Commit f033b688 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
Browse files

xdp: add tracepoints for XDP mem 



These tracepoints make it easier to troubleshoot XDP mem id disconnect.

The xdp:mem_disconnect tracepoint cannot be replaced via kprobe. It is
placed at the last stable place for the pointer to struct xdp_mem_allocator,
just before it's scheduled for RCU removal. It also extract info on
'safe_to_remove' and 'force'.

Detailed info about in-flight pages is not available at this layer. The next
patch will added tracepoints needed at the page_pool layer for this.

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d956a048

include/net/xdp_priv.h

0 → 100644
+23 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __LINUX_NET_XDP_PRIV_H__

#define __LINUX_NET_XDP_PRIV_H__



#include <linux/rhashtable.h>



/* Private to net/core/xdp.c, but used by trace/events/xdp.h */

struct xdp_mem_allocator {

	struct xdp_mem_info mem;

	union {

		void *allocator;

		struct page_pool *page_pool;

		struct zero_copy_allocator *zc_alloc;

	};

	int disconnect_cnt;

	unsigned long defer_start;

	struct rhash_head node;

	struct rcu_head rcu;

	struct delayed_work defer_wq;

	unsigned long defer_warn;

};



#endif /* __LINUX_NET_XDP_PRIV_H__ */

include/trace/events/xdp.h

+115 −0
Original line number Diff line number Diff line
@@ -269,6 +269,121 @@ TRACE_EVENT(xdp_devmap_xmit, 
		  __entry->from_ifindex, __entry->to_ifindex, __entry->err)

);



/* Expect users already include <net/xdp.h>, but not xdp_priv.h */

#include <net/xdp_priv.h>



#define __MEM_TYPE_MAP(FN)	\

	FN(PAGE_SHARED)		\

	FN(PAGE_ORDER0)		\

	FN(PAGE_POOL)		\

	FN(ZERO_COPY)



#define __MEM_TYPE_TP_FN(x)	\

	TRACE_DEFINE_ENUM(MEM_TYPE_##x);

#define __MEM_TYPE_SYM_FN(x)	\

	{ MEM_TYPE_##x, #x },

#define __MEM_TYPE_SYM_TAB	\

	__MEM_TYPE_MAP(__MEM_TYPE_SYM_FN) { -1, 0 }

__MEM_TYPE_MAP(__MEM_TYPE_TP_FN)



TRACE_EVENT(mem_disconnect,



	TP_PROTO(const struct xdp_mem_allocator *xa,

		 bool safe_to_remove, bool force),



	TP_ARGS(xa, safe_to_remove, force),



	TP_STRUCT__entry(

		__field(const struct xdp_mem_allocator *,	xa)

		__field(u32,		mem_id)

		__field(u32,		mem_type)

		__field(const void *,	allocator)

		__field(bool,		safe_to_remove)

		__field(bool,		force)

		__field(int,		disconnect_cnt)

	),



	TP_fast_assign(

		__entry->xa		= xa;

		__entry->mem_id		= xa->mem.id;

		__entry->mem_type	= xa->mem.type;

		__entry->allocator	= xa->allocator;

		__entry->safe_to_remove	= safe_to_remove;

		__entry->force		= force;

		__entry->disconnect_cnt	= xa->disconnect_cnt;

	),



	TP_printk("mem_id=%d mem_type=%s allocator=%p"

		  " safe_to_remove=%s force=%s disconnect_cnt=%d",

		  __entry->mem_id,

		  __print_symbolic(__entry->mem_type, __MEM_TYPE_SYM_TAB),

		  __entry->allocator,

		  __entry->safe_to_remove ? "true" : "false",

		  __entry->force ? "true" : "false",

		  __entry->disconnect_cnt

	)

);



TRACE_EVENT(mem_connect,



	TP_PROTO(const struct xdp_mem_allocator *xa,

		 const struct xdp_rxq_info *rxq),



	TP_ARGS(xa, rxq),



	TP_STRUCT__entry(

		__field(const struct xdp_mem_allocator *,	xa)

		__field(u32,		mem_id)

		__field(u32,		mem_type)

		__field(const void *,	allocator)

		__field(const struct xdp_rxq_info *,		rxq)

		__field(int,		ifindex)

	),



	TP_fast_assign(

		__entry->xa		= xa;

		__entry->mem_id		= xa->mem.id;

		__entry->mem_type	= xa->mem.type;

		__entry->allocator	= xa->allocator;

		__entry->rxq		= rxq;

		__entry->ifindex	= rxq->dev->ifindex;

	),



	TP_printk("mem_id=%d mem_type=%s allocator=%p"

		  " ifindex=%d",

		  __entry->mem_id,

		  __print_symbolic(__entry->mem_type, __MEM_TYPE_SYM_TAB),

		  __entry->allocator,

		  __entry->ifindex

	)

);



TRACE_EVENT(mem_return_failed,



	TP_PROTO(const struct xdp_mem_info *mem,

		 const struct page *page),



	TP_ARGS(mem, page),



	TP_STRUCT__entry(

		__field(const struct page *,	page)

		__field(u32,		mem_id)

		__field(u32,		mem_type)

	),



	TP_fast_assign(

		__entry->page		= page;

		__entry->mem_id		= mem->id;

		__entry->mem_type	= mem->type;

	),



	TP_printk("mem_id=%d mem_type=%s page=%p",

		  __entry->mem_id,

		  __print_symbolic(__entry->mem_type, __MEM_TYPE_SYM_TAB),

		  __entry->page

	)

);



#endif /* _TRACE_XDP_H */



#include <trace/define_trace.h>

net/core/xdp.c

+5 −16
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <net/page_pool.h>



#include <net/xdp.h>

#include <net/xdp_priv.h> /* struct xdp_mem_allocator */

#include <trace/events/xdp.h>



#define REG_STATE_NEW		0x0

#define REG_STATE_REGISTERED	0x1
@@ -29,21 +31,6 @@ static int mem_id_next = MEM_ID_MIN; 
static bool mem_id_init; /* false */

static struct rhashtable *mem_id_ht;



struct xdp_mem_allocator {

	struct xdp_mem_info mem;

	union {

		void *allocator;

		struct page_pool *page_pool;

		struct zero_copy_allocator *zc_alloc;

	};

	struct rhash_head node;

	struct rcu_head rcu;

	struct delayed_work defer_wq;

	unsigned long defer_start;

	unsigned long defer_warn;

	int disconnect_cnt;

};



static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)

{

	const u32 *k = data;
@@ -117,7 +104,7 @@ bool __mem_id_disconnect(int id, bool force) 
	if (xa->mem.type == MEM_TYPE_PAGE_POOL)

		safe_to_remove = page_pool_request_shutdown(xa->page_pool);



	/* TODO: Tracepoint will be added here in next-patch */

	trace_mem_disconnect(xa, safe_to_remove, force);



	if ((safe_to_remove || force) &&

	    !rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
@@ -385,6 +372,7 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 


	mutex_unlock(&mem_id_lock);



	trace_mem_connect(xdp_alloc, xdp_rxq);

	return 0;

err:

	mutex_unlock(&mem_id_lock);
@@ -417,6 +405,7 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, 
		} else {

			/* Hopefully stack show who to blame for late return */

			WARN_ONCE(1, "page_pool gone mem.id=%d", mem->id);

			trace_mem_return_failed(mem, page);

			put_page(page);

		}

		rcu_read_unlock();

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