diff options
Diffstat (limited to 'target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch')
| -rw-r--r-- | target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch b/target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch new file mode 100644 index 0000000000..a25cdb5717 --- /dev/null +++ b/target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch @@ -0,0 +1,38 @@ +From a9b204d1564702b704ad6fe74f10a102c7b87ba3 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet <edumazet@google.com> +Date: Sat, 3 Dec 2016 11:14:53 -0800 +Subject: [PATCH 04/10] tcp: tsq: avoid one atomic in tcp_wfree() + +Under high load, tcp_wfree() has an atomic operation trying +to schedule a tasklet over and over. + +We can schedule it only if our per cpu list was empty. + +Signed-off-by: Eric Dumazet <edumazet@google.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + net/ipv4/tcp_output.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +--- a/net/ipv4/tcp_output.c ++++ b/net/ipv4/tcp_output.c +@@ -880,6 +880,7 @@ void tcp_wfree(struct sk_buff *skb) + + for (oval = READ_ONCE(tp->tsq_flags);; oval = nval) { + struct tsq_tasklet *tsq; ++ bool empty; + + if (!(oval & TSQF_THROTTLED) || (oval & TSQF_QUEUED)) + goto out; +@@ -892,8 +893,10 @@ void tcp_wfree(struct sk_buff *skb) + /* queue this socket to tasklet queue */ + local_irq_save(flags); + tsq = this_cpu_ptr(&tsq_tasklet); ++ empty = list_empty(&tsq->head); + list_add(&tp->tsq_node, &tsq->head); +- tasklet_schedule(&tsq->tasklet); ++ if (empty) ++ tasklet_schedule(&tsq->tasklet); + local_irq_restore(flags); + return; + } |