This commit introduces static perf tracepoints for AF_XDP which
report information about packet drops, such as the netdev, qid and
high level reason for the drop. The tracepoint can be
enabled/disabled by toggling
/sys/kernel/debug/tracing/events/xsk/xsk_packet_drop/enable
Signed-off-by: Ciara Loftus <ciara.loftus@xxxxxxxxx>
---
MAINTAINERS | 1 +
include/linux/bpf_trace.h | 1 +
include/trace/events/xsk.h | 45 +++++++++++++++++++++++++++++++
include/uapi/linux/if_xdp.h | 8 ++++++
kernel/bpf/core.c | 1 +
net/xdp/xsk.c | 5 ++++
net/xdp/xsk_buff_pool.c | 8 +++++-
tools/include/uapi/linux/if_xdp.h | 8 ++++++
8 files changed, 76 insertions(+), 1 deletion(-)
create mode 100644 include/trace/events/xsk.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 1df56a32d2df..efe6662d4198 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19440,6 +19440,7 @@ S: Maintained
F: Documentation/networking/af_xdp.rst
F: include/net/xdp_sock*
F: include/net/xsk_buff_pool.h
+F: include/trace/events/xsk.h
F: include/uapi/linux/if_xdp.h
F: include/uapi/linux/xdp_diag.h
F: include/net/netns/xdp.h
diff --git a/include/linux/bpf_trace.h b/include/linux/bpf_trace.h
index ddf896abcfb6..477d29b6c2c1 100644
--- a/include/linux/bpf_trace.h
+++ b/include/linux/bpf_trace.h
@@ -3,5 +3,6 @@
#define __LINUX_BPF_TRACE_H__
#include <trace/events/xdp.h>
+#include <trace/events/xsk.h>
#endif /* __LINUX_BPF_TRACE_H__ */
diff --git a/include/trace/events/xsk.h b/include/trace/events/xsk.h
new file mode 100644
index 000000000000..4f5629ba1b0f
--- /dev/null
+++ b/include/trace/events/xsk.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2021 Intel Corporation. */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM xsk
+
+#if !defined(_TRACE_XSK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_XSK_H
+
+#include <linux/if_xdp.h>
+#include <linux/tracepoint.h>
+
+#define print_reason(val) \
+ __print_symbolic(val, \
+ { XSK_TRACE_DROP_RXQ_FULL, "rxq full" }, \
+ { XSK_TRACE_DROP_PKT_TOO_BIG, "packet too big" }, \
+ { XSK_TRACE_DROP_FQ_EMPTY, "fq empty" }, \
+ { XSK_TRACE_DROP_POOL_EMPTY, "xskb pool empty" }, \
+ { XSK_TRACE_DROP_DRV_ERR_TX, "driver error on tx" })
+
+TRACE_EVENT(xsk_packet_drop,
+
+ TP_PROTO(char *name, u16 queue_id, u32 reason),
+
+ TP_ARGS(name, queue_id, reason),
+
+ TP_STRUCT__entry(
+ __field(char *, name)
+ __field(u16, queue_id)
+ __field(u32, reason)
+ ),
+
+ TP_fast_assign(
+ __entry->name = name;
+ __entry->queue_id = queue_id;
+ __entry->reason = reason;
+ ),
+
+ TP_printk("netdev: %s qid %u reason: %s", __entry->name,
+ __entry->queue_id, print_reason(__entry->reason))
+);
+
+#endif /* _TRACE_XSK_H */
+
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index a78a8096f4ce..5f1b8bf99bb5 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -108,4 +108,12 @@ struct xdp_desc {
/* UMEM descriptor is __u64 */
+enum xdp_trace_reasons {
+ XSK_TRACE_DROP_RXQ_FULL,
+ XSK_TRACE_DROP_PKT_TOO_BIG,
+ XSK_TRACE_DROP_FQ_EMPTY,
+ XSK_TRACE_DROP_POOL_EMPTY,
+ XSK_TRACE_DROP_DRV_ERR_TX,
+};
+
#endif /* _LINUX_IF_XDP_H */
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 5bbd4884ff7a..442b0d7f9bf8 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2362,3 +2362,4 @@ EXPORT_SYMBOL(bpf_stats_enabled_key);
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
+EXPORT_TRACEPOINT_SYMBOL_GPL(xsk_packet_drop);
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 4faabd1ecfd1..9b850716630b 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -11,6 +11,7 @@
#define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
+#include <linux/bpf_trace.h>
#include <linux/if_xdp.h>
#include <linux/init.h>
#include <linux/sched/mm.h>
@@ -158,6 +159,7 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
addr = xp_get_handle(xskb);
err = xskq_prod_reserve_desc(xs->rx, addr, len);
if (err) {
+ trace_xsk_packet_drop(xs->dev->name, xs->queue_id, XSK_TRACE_DROP_RXQ_FULL);
xs->rx_queue_full++;
return err;
}
@@ -192,6 +194,7 @@ static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
len = xdp->data_end - xdp->data;
if (len > xsk_pool_get_rx_frame_size(xs->pool)) {
+ trace_xsk_packet_drop(xs->dev->name, xs->queue_id, XSK_TRACE_DROP_PKT_TOO_BIG);
xs->rx_dropped++;
return -ENOSPC;
}
@@ -516,6 +519,8 @@ static int xsk_generic_xmit(struct sock *sk)
if (err == NET_XMIT_DROP) {
/* SKB completed but not sent */
err = -EBUSY;
+ trace_xsk_packet_drop(xs->dev->name, xs->queue_id,
+ XSK_TRACE_DROP_DRV_ERR_TX);
goto out;
}
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 8de01aaac4a0..d3c1ca83c75d 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf_trace.h>
#include <net/xsk_buff_pool.h>
#include <net/xdp_sock.h>
#include <net/xdp_sock_drv.h>
@@ -445,8 +446,11 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
u64 addr;
bool ok;
- if (pool->free_heads_cnt == 0)
+ if (pool->free_heads_cnt == 0) {
+ trace_xsk_packet_drop(pool->netdev->name, pool->queue_id,
+ XSK_TRACE_DROP_POOL_EMPTY);
return NULL;
+ }
xskb = pool->free_heads[--pool->free_heads_cnt];
@@ -454,6 +458,8 @@ static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
pool->fq->queue_empty_descs++;
xp_release(xskb);
+ trace_xsk_packet_drop(pool->netdev->name, pool->queue_id,
+ XSK_TRACE_DROP_FQ_EMPTY);
return NULL;
}
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index a78a8096f4ce..5f1b8bf99bb5 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -108,4 +108,12 @@ struct xdp_desc {
/* UMEM descriptor is __u64 */
+enum xdp_trace_reasons {
+ XSK_TRACE_DROP_RXQ_FULL,
+ XSK_TRACE_DROP_PKT_TOO_BIG,
+ XSK_TRACE_DROP_FQ_EMPTY,
+ XSK_TRACE_DROP_POOL_EMPTY,
+ XSK_TRACE_DROP_DRV_ERR_TX,
+};
+
#endif /* _LINUX_IF_XDP_H */
--
2.17.1
