linux/net/sched
Herbert Xu 48d83325b6 [NET]: Prevent multiple qdisc runs
Having two or more qdisc_run's contend against each other is bad because
it can induce packet reordering if the packets have to be requeued.  It
appears that this is an unintended consequence of relinquinshing the queue
lock while transmitting.  That in turn is needed for devices that spend a
lot of time in their transmit routine.

There are no advantages to be had as devices with queues are inherently
single-threaded (the loopback device is not but then it doesn't have a
queue).

Even if you were to add a queue to a parallel virtual device (e.g., bolt
a tbf filter in front of an ipip tunnel device), you would still want to
process the queue in sequence to ensure that the packets are ordered
correctly.

The solution here is to steal a bit from net_device to prevent this.

BTW, as qdisc_restart is no longer used by anyone as a module inside the
kernel (IIRC it used to with netif_wake_queue), I have not exported the
new __qdisc_run function.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-19 23:57:59 -07:00
..
act_api.c [NET_SCHED]: act_api: fix skb leak in error path 2006-03-12 20:39:36 -08:00
act_gact.c [PKT_SCHED]: Prefix tc actions with act_ 2006-01-09 14:16:14 -08:00
act_ipt.c [NETFILTER]: ipt action: use xt_check_target for basic verification 2006-04-24 17:27:34 -07:00
act_mirred.c [PKT_SCHED]: Prefix tc actions with act_ 2006-01-09 14:16:14 -08:00
act_pedit.c [PKT_SCHED]: Prefix tc actions with act_ 2006-01-09 14:16:14 -08:00
act_police.c [PKT_SCHED] act_police: Rename methods. 2006-04-09 22:25:46 -07:00
act_simple.c [PKT_SCHED]: Prefix tc actions with act_ 2006-01-09 14:16:14 -08:00
cls_api.c [NETLINK]: Convert netlink users to use group numbers instead of bitmasks 2005-08-29 16:00:54 -07:00
cls_basic.c [PKT_SCHED]: Dump classification result for basic classifier 2005-06-08 15:11:02 -07:00
cls_fw.c [NET]: kfree cleanup 2005-11-08 09:41:34 -08:00
cls_route.c [NET]: kfree cleanup 2005-11-08 09:41:34 -08:00
cls_rsvp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cls_rsvp.h [NET]: kfree cleanup 2005-11-08 09:41:34 -08:00
cls_rsvp6.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cls_tcindex.c [NET]: kfree cleanup 2005-11-08 09:41:34 -08:00
cls_u32.c [NET_SCHED]: cls_u32: remove unnecessary NULL-ptr check 2006-03-23 01:16:48 -08:00
em_cmp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
em_meta.c [NET]: kfree cleanup 2005-11-08 09:41:34 -08:00
em_nbyte.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
em_text.c [PKT_SCHED]: Remove debugging leftover from textsearch ematch 2005-07-18 13:29:49 -07:00
em_u32.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ematch.c [PKT_SCHED] ematch: Remove bogus include. 2006-01-11 16:32:16 -08:00
estimator.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Kconfig [PKT_SCHED]: Let NET_CLS_ACT no longer depend on EXPERIMENTAL 2006-03-20 22:44:24 -08:00
Makefile [PKT_SCHED]: Prefix tc actions with act_ 2006-01-09 14:16:14 -08:00
sch_api.c [PATCH] timer initialization cleanup: DEFINE_TIMER 2005-09-09 14:03:48 -07:00
sch_atm.c [PKT_SCHED]: Dump child qdisc handle in sch_{atm,dsmark} 2006-03-20 19:01:06 -08:00
sch_blackhole.c [PKT_SCHED]: Blackhole queueing discipline 2005-07-05 15:29:16 -07:00
sch_cbq.c [PKT_SCHED]: Fix qdisc return code. 2006-01-09 14:16:26 -08:00
sch_dsmark.c [PKT_SCHED]: Dump child qdisc handle in sch_{atm,dsmark} 2006-03-20 19:01:06 -08:00
sch_fifo.c [PKT_SCHED]: Cleanup fifo qdisc and remove unnecessary code 2005-06-18 22:58:00 -07:00
sch_generic.c [NET]: Prevent multiple qdisc runs 2006-06-19 23:57:59 -07:00
sch_gred.c [PKT_SCHED]: (G)RED: Introduce hard dropping 2005-11-05 22:02:29 +01:00
sch_hfsc.c [NET_SCHED]: HFSC: fix thinko in hfsc_adjust_levels() 2006-05-11 12:22:03 -07:00
sch_htb.c [PKT_SCHED]: Fix qdisc return code. 2006-01-09 14:16:26 -08:00
sch_ingress.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sch_netem.c [PKT_SCHED] netem: fix loss 2006-04-29 18:33:12 -07:00
sch_prio.c [PKT_SCHED]: Qdisc drop operation is optional 2006-03-20 19:00:49 -08:00
sch_red.c [PKT_SCHED]: Convert sch_red to a classful qdisc 2006-03-20 19:20:44 -08:00
sch_sfq.c [PKT_SCHED]: Keep backlog counter in sch_sfq 2006-03-20 19:01:38 -08:00
sch_tbf.c [PKT_SCHED]: Restore TBF change semantic 2006-03-20 19:01:21 -08:00
sch_teql.c [NET]: Add netif_tx_lock 2006-06-17 21:30:14 -07:00