openwrt/target/linux/generic/backport-4.9/025-tcp-allow-drivers-to-tweak-TSQ-logic.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  - target/linux/ar71xx/patches-4.9/103-MIPS-ath79-fix-register-address-in-ath79_ddr_wb_flus.patch superseded by upstream
  - target/linux/ar71xx/patches-4.9/403-mtd_fix_cfi_cmdset_0002_status_check.patch superseded by upstream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

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From: Eric Dumazet <edumazet@google.com>
Date: Sat, 11 Nov 2017 15:54:12 -0800
Subject: [PATCH] tcp: allow drivers to tweak TSQ logic
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
I had many reports that TSQ logic breaks wifi aggregation.
Current logic is to allow up to 1 ms of bytes to be queued into qdisc
and drivers queues.
But Wifi aggregation needs a bigger budget to allow bigger rates to
be discovered by various TCP Congestion Controls algorithms.
This patch adds an extra socket field, allowing wifi drivers to select
another log scale to derive TCP Small Queue credit from current pacing
rate.
Initial value is 10, meaning that this patch does not change current
behavior.
We expect wifi drivers to set this field to smaller values (tests have
been done with values from 6 to 9)
They would have to use following template :
if (skb->sk && skb->sk->sk_pacing_shift != MY_PACING_SHIFT)
skb->sk->sk_pacing_shift = MY_PACING_SHIFT;
Ref: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1670041
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Toke Høiland-Jørgensen <toke@toke.dk>
Cc: Kir Kolyshkin <kir@openvz.org>
---
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -260,6 +260,7 @@ struct sock_common {
* @sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
* @sk_gso_max_size: Maximum GSO segment size to build
* @sk_gso_max_segs: Maximum number of GSO segments
+ * @sk_pacing_shift: scaling factor for TCP Small Queues
* @sk_lingertime: %SO_LINGER l_linger setting
* @sk_backlog: always used with the per-socket spinlock held
* @sk_callback_lock: used with the callbacks in the end of this struct
@@ -421,6 +422,8 @@ struct sock {
kmemcheck_bitfield_end(flags);
u16 sk_gso_max_segs;
+#define sk_pacing_shift sk_pacing_shift /* for backport checks */
+ u8 sk_pacing_shift;
unsigned long sk_lingertime;
struct proto *sk_prot_creator;
rwlock_t sk_callback_lock;
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2475,6 +2475,7 @@ void sock_init_data(struct socket *sock,
sk->sk_max_pacing_rate = ~0U;
sk->sk_pacing_rate = ~0U;
+ sk->sk_pacing_shift = 10;
sk->sk_incoming_cpu = -1;
/*
* Before updating sk_refcnt, we must commit prior changes to memory
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1593,7 +1593,7 @@ u32 tcp_tso_autosize(const struct sock *
{
u32 bytes, segs;
- bytes = min(sk->sk_pacing_rate >> 10,
+ bytes = min(sk->sk_pacing_rate >> sk->sk_pacing_shift,
sk->sk_gso_max_size - 1 - MAX_TCP_HEADER);
/* Goal is to send at least one packet per ms,
@@ -2123,7 +2123,7 @@ static bool tcp_small_queue_check(struct
{
unsigned int limit;
- limit = max(2 * skb->truesize, sk->sk_pacing_rate >> 10);
+ limit = max(2 * skb->truesize, sk->sk_pacing_rate >> sk->sk_pacing_shift);
limit = min_t(u32, limit, sysctl_tcp_limit_output_bytes);
limit <<= factor;