Venkatesh Pallipadi 49c6f4a2ba sched: Fix softirq time accounting ... Commit: 75e1056f5c upstream Peter Zijlstra found a bug in the way softirq time is accounted in VIRT_CPU_ACCOUNTING on this thread: http://lkml.indiana.edu/hypermail//linux/kernel/1009.2/01366.html The problem is, softirq processing uses local_bh_disable internally. There is no way, later in the flow, to differentiate between whether softirq is being processed or is it just that bh has been disabled. So, a hardirq when bh is disabled results in time being wrongly accounted as softirq. Looking at the code a bit more, the problem exists in !VIRT_CPU_ACCOUNTING as well. As account_system_time() in normal tick based accouting also uses softirq_count, which will be set even when not in softirq with bh disabled. Peter also suggested solution of using 2*SOFTIRQ_OFFSET as irq count for local_bh_{disable,enable} and using just SOFTIRQ_OFFSET while softirq processing. The patch below does that and adds API in_serving_softirq() which returns whether we are currently processing softirq or not. Also changes one of the usages of softirq_count in net/sched/cls_cgroup.c to in_serving_softirq. Looks like many usages of in_softirq really want in_serving_softirq. Those changes can be made individually on a case by case basis. Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1286237003-12406-2-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>		2011-02-17 15:37:24 -08:00
..
act_api.c
act_gact.c	net sched: fix some kernel memory leaks	2010-12-09 13:27:14 -08:00
act_ipt.c
act_mirred.c	net sched: fix some kernel memory leaks	2010-12-09 13:27:14 -08:00
act_nat.c	net sched: fix some kernel memory leaks	2010-12-09 13:27:14 -08:00
act_pedit.c
act_police.c	net sched: fix kernel leak in act_police	2010-12-09 13:27:05 -08:00
act_simple.c	net sched: fix some kernel memory leaks	2010-12-09 13:27:14 -08:00
act_skbedit.c	net sched: fix some kernel memory leaks	2010-12-09 13:27:14 -08:00
cls_api.c
cls_basic.c
cls_cgroup.c	sched: Fix softirq time accounting	2011-02-17 15:37:24 -08:00
cls_flow.c
cls_fw.c
cls_route.c
cls_rsvp.c
cls_rsvp.h
cls_rsvp6.c
cls_tcindex.c
cls_u32.c
em_cmp.c
em_meta.c
em_nbyte.c
em_text.c
em_u32.c
ematch.c
Kconfig
Makefile
sch_api.c
sch_atm.c
sch_blackhole.c
sch_cbq.c
sch_drr.c
sch_dsmark.c
sch_fifo.c
sch_generic.c
sch_gred.c
sch_hfsc.c
sch_htb.c
sch_ingress.c
sch_mq.c
sch_multiq.c
sch_netem.c
sch_prio.c
sch_red.c
sch_sfq.c
sch_tbf.c
sch_teql.c