diff options
Diffstat (limited to 'target/linux/generic/backport-4.9')
| -rw-r--r-- | target/linux/generic/backport-4.9/025-tcp-allow-drivers-to-tweak-TSQ-logic.patch | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.9/025-tcp-allow-drivers-to-tweak-TSQ-logic.patch b/target/linux/generic/backport-4.9/025-tcp-allow-drivers-to-tweak-TSQ-logic.patch new file mode 100644 index 0000000000..446730ed16 --- /dev/null +++ b/target/linux/generic/backport-4.9/025-tcp-allow-drivers-to-tweak-TSQ-logic.patch @@ -0,0 +1,85 @@ +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 +@@ -2478,6 +2478,7 @@ 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 +@@ -1581,7 +1581,7 @@ 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, +@@ -2083,7 +2083,7 @@ 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; + |