You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
38 lines
1.2 KiB
38 lines
1.2 KiB
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;
|
|
}
|
|
|