kernel_optimize_test/net
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
..
9p
802
8021q
appletalk
atm
ax25
batman-adv
bluetooth
bridge
caif CAIF: fix sparse warning for caif_usb 2013-03-04 14:12:07 -05:00
can
ceph
core
dcb
dccp
decnet
dns_resolver
dsa
ethernet
ieee802154
ipv4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
ipv6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
ipx
irda net/irda: Raise dtr in non-blocking open 2013-03-06 02:47:05 -05:00
iucv
key
l2tp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
lapb
llc
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
mac802154
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
netlabel
netlink
netrom
nfc
openvswitch
packet
phonet
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
rfkill
rose
rxrpc
sched pkt_sched: sch_qfq: prevent budget from wrapping around after a dequeue 2013-03-06 02:47:05 -05:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-03-05 18:42:29 -08:00
sunrpc NFS client bugfixes for Linux 3.9 2013-03-02 16:46:07 -08:00
tipc
unix
vmw_vsock
wimax
wireless
x25
xfrm
compat.c
Kconfig
Makefile
nonet.c
socket.c
sysctl_net.c