kernel_optimize_test/net/sched
Paolo Valente a0143efa96 pkt_sched: sch_qfq: prevent budget from wrapping around after a dequeue
Aggregate budgets are computed so as to guarantee that, after an
aggregate has been selected for service, that aggregate has enough
budget to serve at least one maximum-size packet for the classes it
contains. For this reason, after a new aggregate has been selected
for service, its next packet is immediately dequeued, without any
further control.

The maximum packet size for a class, lmax, can be changed through
qfq_change_class(). In case the user sets lmax to a lower value than
the the size of some of the still-to-arrive packets, QFQ+ will
automatically push up lmax as it enqueues these packets.  This
automatic push up is likely to happen with TSO/GSO.

In any case, if lmax is assigned a lower value than the size of some
of the packets already enqueued for the class, then the following
problem may occur: the size of the next packet to dequeue for the
class may happen to be larger than lmax, after the aggregate to which
the class belongs has been just selected for service. In this case,
even the budget of the aggregate, which is an unsigned value, may be
lower than the size of the next packet to dequeue. After dequeueing
this packet and subtracting its size from the budget, the latter would
wrap around.

This fix prevents the budget from wrapping around after any packet
dequeue.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Reviewed-by: Fabio Checconi <fchecconi@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-06 02:47:05 -05:00
..
act_api.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_csum.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_gact.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_ipt.c net: Add skb_unclone() helper function. 2013-02-15 15:10:37 -05:00
act_mirred.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_nat.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_pedit.c net: Add skb_unclone() helper function. 2013-02-15 15:10:37 -05:00
act_police.c act_police: improved accuracy at high rates 2013-02-12 18:59:45 -05:00
act_simple.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
act_skbedit.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_api.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_basic.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_cgroup.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_flow.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_fw.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_route.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_rsvp.c
cls_rsvp.h pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_rsvp6.c
cls_tcindex.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
cls_u32.c pkt_sched: namespace aware act_mirred 2013-01-14 15:09:36 -05:00
em_canid.c
em_cmp.c
em_ipset.c
em_meta.c
em_nbyte.c
em_text.c
em_u32.c
ematch.c
Kconfig net: sched: enable CAN Identifier to be build into kernel 2012-11-25 16:06:06 -05:00
Makefile
sch_api.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sch_atm.c
sch_blackhole.c
sch_cbq.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sch_choke.c
sch_codel.c
sch_drr.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sch_dsmark.c
sch_fifo.c
sch_fq_codel.c
sch_generic.c sch: make htb_rate_cfg and functions around that generic 2013-02-12 18:59:45 -05:00
sch_gred.c
sch_hfsc.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sch_htb.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sch_ingress.c
sch_mq.c pkt_sched: avoid requeues if possible 2012-12-12 00:16:47 -05:00
sch_mqprio.c pkt_sched: avoid requeues if possible 2012-12-12 00:16:47 -05:00
sch_multiq.c
sch_netem.c netem: fix delay calculation in rate extension 2013-01-29 15:43:02 -05:00
sch_plug.c
sch_prio.c
sch_qfq.c pkt_sched: sch_qfq: prevent budget from wrapping around after a dequeue 2013-03-06 02:47:05 -05:00
sch_red.c
sch_sfb.c
sch_sfq.c
sch_tbf.c tbf: improved accuracy at high rates 2013-02-12 18:59:45 -05:00
sch_teql.c