[net-next PATCH v2 6/8] net: Commonize busy polling code to focus on napi_id instead of socket

From: Alexander Duyck
Date: Thu Mar 23 2017 - 17:39:16 EST


From: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx>

Move the core functionality in sk_busy_loop() to napi_busy_loop() and
make it independent of sk.

This enables re-using this function in epoll busy loop implementation.

Signed-off-by: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
---
include/net/busy_poll.h | 20 +++++++++++++++-----
net/core/dev.c | 21 ++++++++-------------
net/core/sock.c | 11 +++++++++++
3 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h
index 4626cb22f625..336a874c0fed 100644
--- a/include/net/busy_poll.h
+++ b/include/net/busy_poll.h
@@ -61,7 +61,11 @@ static inline bool sk_can_busy_loop(const struct sock *sk)
return sk->sk_ll_usec && !signal_pending(current);
}

-void sk_busy_loop(struct sock *sk, int nonblock);
+bool sk_busy_loop_end(void *p, unsigned long start_time);
+
+void napi_busy_loop(unsigned int napi_id,
+ bool (*loop_end)(void *, unsigned long),
+ void *loop_end_arg);

#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
@@ -74,10 +78,6 @@ static inline bool sk_can_busy_loop(struct sock *sk)
return false;
}

-static inline void sk_busy_loop(struct sock *sk, int nonblock)
-{
-}
-
#endif /* CONFIG_NET_RX_BUSY_POLL */

static inline unsigned long busy_loop_current_time(void)
@@ -121,6 +121,16 @@ static inline bool sk_busy_loop_timeout(struct sock *sk,
return true;
}

+static inline void sk_busy_loop(struct sock *sk, int nonblock)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
+
+ if (napi_id >= MIN_NAPI_ID)
+ napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
+#endif
+}
+
/* used in the NIC receive handler to mark the skb */
static inline void skb_mark_napi_id(struct sk_buff *skb,
struct napi_struct *napi)
diff --git a/net/core/dev.c b/net/core/dev.c
index 73ebf2f5600e..b082f70e50c5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5060,20 +5060,17 @@ static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock)
do_softirq();
}

-void sk_busy_loop(struct sock *sk, int nonblock)
+void napi_busy_loop(unsigned int napi_id,
+ bool (*loop_end)(void *, unsigned long),
+ void *loop_end_arg)
{
- unsigned long start_time = nonblock ? 0 : busy_loop_current_time();
+ unsigned long start_time = loop_end ? busy_loop_current_time() : 0;
int (*napi_poll)(struct napi_struct *napi, int budget);
void *have_poll_lock = NULL;
struct napi_struct *napi;
- unsigned int napi_id;
int work;

restart:
- napi_id = READ_ONCE(sk->sk_napi_id);
- if (napi_id < MIN_NAPI_ID)
- return;
-
work = 0;
napi_poll = NULL;

@@ -5107,12 +5104,11 @@ void sk_busy_loop(struct sock *sk, int nonblock)
trace_napi_poll(napi, work, BUSY_POLL_BUDGET);
count:
if (work > 0)
- __NET_ADD_STATS(sock_net(sk),
+ __NET_ADD_STATS(dev_net(napi->dev),
LINUX_MIB_BUSYPOLLRXPACKETS, work);
local_bh_enable();

- if (nonblock || !skb_queue_empty(&sk->sk_receive_queue) ||
- sk_busy_loop_timeout(sk, start_time))
+ if (!loop_end || loop_end(loop_end_arg, start_time))
break;

if (unlikely(need_resched())) {
@@ -5121,8 +5117,7 @@ void sk_busy_loop(struct sock *sk, int nonblock)
preempt_enable();
rcu_read_unlock();
cond_resched();
- if (!skb_queue_empty(&sk->sk_receive_queue) ||
- sk_busy_loop_timeout(sk, start_time))
+ if (loop_end(loop_end_arg, start_time))
return;
goto restart;
}
@@ -5134,7 +5129,7 @@ void sk_busy_loop(struct sock *sk, int nonblock)
out:
rcu_read_unlock();
}
-EXPORT_SYMBOL(sk_busy_loop);
+EXPORT_SYMBOL(napi_busy_loop);

#endif /* CONFIG_NET_RX_BUSY_POLL */

diff --git a/net/core/sock.c b/net/core/sock.c
index f8c0373a3a74..0aa725cb3dd6 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3231,3 +3231,14 @@ static int __init proto_init(void)
subsys_initcall(proto_init);

#endif /* PROC_FS */
+
+#ifdef CONFIG_NET_RX_BUSY_POLL
+bool sk_busy_loop_end(void *p, unsigned long start_time)
+{
+ struct sock *sk = p;
+
+ return !skb_queue_empty(&sk->sk_receive_queue) ||
+ sk_busy_loop_timeout(sk, start_time);
+}
+EXPORT_SYMBOL(sk_busy_loop_end);
+#endif /* CONFIG_NET_RX_BUSY_POLL */