From: Eric Dumazet <eduma...@google.com>
If tcp_send_ack() can not allocate skb, we properly handle this
and setup a timer to try later.
Use __GFP_NOWARN to avoid polluting syslog in the case host is
under memory pressure, so that pertinent messages are not lost under
a flood of useless information.
sk_gfp_atomic() can use its gfp_mask argument (all callers currently
were using GFP_ATOMIC before this patch)
Note that when tcp_transmit_skb() is called with clone_it set to false,
we do not attempt memory allocations, so can pass a 0 gfp_mask, which
most compilers can emit faster than a non zero value.
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
include/net/sock.h | 2 +-
net/ipv4/tcp_output.c | 12 +++++++-----
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 7f89e4ba18d1..ead514332ae8 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -776,7 +776,7 @@ static inline int sk_memalloc_socks(void)
static inline gfp_t sk_gfp_atomic(const struct sock *sk, gfp_t gfp_mask)
{
- return GFP_ATOMIC | (sk->sk_allocation & __GFP_MEMALLOC);
+ return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
}
static inline void sk_acceptq_removed(struct sock *sk)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cb7ca569052c..0a1d4f6ab52f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3352,8 +3352,9 @@ void tcp_send_ack(struct sock *sk)
* tcp_transmit_skb() will set the ownership to this
* sock.
*/
- buff = alloc_skb(MAX_TCP_HEADER, sk_gfp_atomic(sk, GFP_ATOMIC));
- if (!buff) {
+ buff = alloc_skb(MAX_TCP_HEADER,
+ sk_gfp_atomic(sk, GFP_ATOMIC | __GFP_NOWARN));
+ if (unlikely(!buff)) {
inet_csk_schedule_ack(sk);
inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
@@ -3375,7 +3376,7 @@ void tcp_send_ack(struct sock *sk)
/* Send it off, this clears delayed acks for us. */
skb_mstamp_get(&buff->skb_mstamp);
- tcp_transmit_skb(sk, buff, 0, sk_gfp_atomic(sk, GFP_ATOMIC));
+ tcp_transmit_skb(sk, buff, 0, (__force gfp_t)0);
}
EXPORT_SYMBOL_GPL(tcp_send_ack);
@@ -3396,7 +3397,8 @@ static int tcp_xmit_probe_skb(struct sock *sk, int
urgent, int mib)
struct sk_buff *skb;
/* We don't queue it, tcp_transmit_skb() sets ownership. */
- skb = alloc_skb(MAX_TCP_HEADER, sk_gfp_atomic(sk, GFP_ATOMIC));
+ skb = alloc_skb(MAX_TCP_HEADER,
+ sk_gfp_atomic(sk, GFP_ATOMIC | __GFP_NOWARN));
if (!skb)
return -1;
@@ -3409,7 +3411,7 @@ static int tcp_xmit_probe_skb(struct sock *sk, int
urgent, int mib)
tcp_init_nondata_skb(skb, tp->snd_una - !urgent, TCPHDR_ACK);
skb_mstamp_get(&skb->skb_mstamp);
NET_INC_STATS(sock_net(sk), mib);
- return tcp_transmit_skb(sk, skb, 0, GFP_ATOMIC);
+ return tcp_transmit_skb(sk, skb, 0, (__force gfp_t)0);
}
void tcp_send_window_probe(struct sock *sk)
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
