[PATCH] Disable TSO for non standard qdiscs
flat view
STALE6821d
From: Andi Kleen <hidden>
Date: 2008-01-31 12:46:39
TSO interacts badly with many queueing disciplines because they rely on reordering packets from different streams and the large TSO packets can make this difficult. This patch disables TSO for sockets that send over devices with non standard queueing disciplines. That's anything but noop or pfifo_fast and pfifo right now. Longer term other queueing disciplines could be checked if they are also ok with TSO. If yes they can set the TCQ_F_GSO_OK flag too. It is still enabled for the standard pfifo_fast because that will never reorder packets with the same type-of-service. This means 99+% of all users will still be able to use TSO just fine. The status is only set up at socket creation so a shifted route will not reenable TSO on a existing socket. I don't think that's a problem though. Signed-off-by: Andi Kleen <redacted> --- include/net/sch_generic.h | 1 + net/core/sock.c | 3 +++ net/sched/sch_generic.c | 5 +++-- 3 files changed, 7 insertions(+), 2 deletions(-) Index: linux/include/net/sch_generic.h ===================================================================
--- linux.orig/include/net/sch_generic.h
+++ linux/include/net/sch_generic.h@@ -31,6 +31,7 @@ struct Qdisc #define TCQ_F_BUILTIN 1 #define TCQ_F_THROTTLED 2 #define TCQ_F_INGRESS 4 +#define TCQ_F_GSO_OK 8 int padded; struct Qdisc_ops *ops; u32 handle;
Index: linux/net/sched/sch_generic.c ===================================================================
--- linux.orig/net/sched/sch_generic.c
+++ linux/net/sched/sch_generic.c@@ -307,7 +307,7 @@ struct Qdisc_ops noop_qdisc_ops __read_m struct Qdisc noop_qdisc = { .enqueue = noop_enqueue, .dequeue = noop_dequeue, - .flags = TCQ_F_BUILTIN, + .flags = TCQ_F_BUILTIN | TCQ_F_GSO_OK, .ops = &noop_qdisc_ops, .list = LIST_HEAD_INIT(noop_qdisc.list), };
@@ -325,7 +325,7 @@ static struct Qdisc_ops noqueue_qdisc_op static struct Qdisc noqueue_qdisc = { .enqueue = NULL, .dequeue = noop_dequeue, - .flags = TCQ_F_BUILTIN, + .flags = TCQ_F_BUILTIN | TCQ_F_GSO_OK, .ops = &noqueue_qdisc_ops, .list = LIST_HEAD_INIT(noqueue_qdisc.list), };
@@ -538,6 +538,7 @@ void dev_activate(struct net_device *dev printk(KERN_INFO "%s: activation failed\n", dev->name); return; } + qdisc->flags |= TCQ_F_GSO_OK; list_add_tail(&qdisc->list, &dev->qdisc_list); } else { qdisc = &noqueue_qdisc;
Index: linux/net/core/sock.c ===================================================================
--- linux.orig/net/core/sock.c
+++ linux/net/core/sock.c@@ -112,6 +112,7 @@ #include <linux/tcp.h> #include <linux/init.h> #include <linux/highmem.h> +#include <net/sch_generic.h> #include <asm/uaccess.h> #include <asm/system.h>
@@ -1062,6 +1063,8 @@ void sk_setup_caps(struct sock *sk, stru { __sk_dst_set(sk, dst); sk->sk_route_caps = dst->dev->features; + if (!(dst->dev->qdisc->flags & TCQ_F_GSO_OK)) + sk->sk_route_caps &= ~NETIF_F_GSO_MASK; if (sk->sk_route_caps & NETIF_F_GSO) sk->sk_route_caps |= NETIF_F_GSO_SOFTWARE; if (sk_can_gso(sk)) {
Index: linux/net/sched/sch_fifo.c ===================================================================
--- linux.orig/net/sched/sch_fifo.c
+++ linux/net/sched/sch_fifo.c@@ -62,6 +62,7 @@ static int fifo_init(struct Qdisc *sch, q->limit = ctl->limit; } + sch->flags |= TCQ_F_GSO_OK; return 0; }