openwrt/target/linux/generic/backport-4.9/024-4-tcp-tsq-avoid-one-atomic-in-tcp_wfree.patch
Stijn Segers 9e1530b2a3 kernel: bump 4.9 to 4.9.117 for 18.06
* Refreshed patches.
* Removed patches:
  - target/linux/ar71xx/patches-4.9/103-MIPS-ath79-fix-register-address-in-ath79_ddr_wb_flus.patch superseded by upstream
  - target/linux/ar71xx/patches-4.9/403-mtd_fix_cfi_cmdset_0002_status_check.patch superseded by upstream
  - target/linux/brcm63xx/patches-4.9/001-4.11-01-mtd-m25p80-consider-max-message-size-in-m25p80_read.patch accepted upstream
  - target/linux/brcm63xx/patches-4.9/001-4.15-08-bcm63xx_enet-correct-clock-usage.patch accepted upstream
  - target/linux/brcm63xx/patches-4.9/001-4.15-09-bcm63xx_enet-do-not-write-to-random-DMA-channel-on-B.patch accepted upstream
  - target/linux/generic/pending-4.9/900-gen_stats-fix-netlink-stats-padding.patch

* New backported patch to address ext4 breakage, introduced in 4.9.112:
  - backport-4.9/500-ext4-fix-check-to-prevent-initializing-reserved-inod.patch

Also add ARM64_SSBD symbol to ARM64 targets still running kernel 4.9

Thanks to Koen Vandeputte for pointing out the need to add the ARM64_SSBD symbol, and the ext4 patch.

Compile-tested on: ar71xx
Run-tested on: ar71xx

Signed-off-by: Stijn Segers <foss@volatilesystems.org>
2018-08-06 07:30:32 +02:00

39 lines
1.2 KiB
Diff

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
@@ -885,6 +885,7 @@ 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;
@@ -897,8 +898,10 @@ 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;
}