Thomas Gleixner 98d8256739 Prevent going idle with softirq pending ... The NOHZ patch contains a check for softirqs pending when a CPU goes idle. The BUG is unrelated to NOHZ, it just was made visible by the NOHZ patch. The BUG showed up mainly on P4 / hyperthreading enabled machines which lead the investigations into the wrong direction in the first place. The real cause is in cond_resched_softirq(): cond_resched_softirq() is enabling softirqs without invoking the softirq daemon when softirqs are pending. This leads to the warning message in the NOHZ idle code: t1 runs softirq disabled code on CPU#0 interrupt happens, softirq is raised, but deferred (softirqs disabled) t1 calls cond_resched_softirq() enables softirqs via _local_bh_enable() calls schedule() t2 runs t1 is migrated to CPU#1 t2 is done and invokes idle() NOHZ detects the pending softirq Fix: change _local_bh_enable() to local_bh_enable() so the softirq daemon is invoked. Thanks to Anant Nitya for debugging this with great patience ! Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2007-05-23 20:14:15 -07:00
..
irq
power
time
.gitignore
acct.c
audit.c
audit.h
auditfilter.c
auditsc.c
capability.c
compat.c
configs.c
cpu.c
cpuset.c
delayacct.c
die_notifier.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c
futex_compat.c
futex.c
hrtimer.c
itimer.c
kallsyms.c
Kconfig.hz
Kconfig.preempt
kexec.c
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latency.c
lockdep_internals.h
lockdep_proc.c
lockdep.c
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
nsproxy.c
panic.c
params.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
rcupdate.c
rcutorture.c
relay.c
resource.c
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched.c
seccomp.c
signal.c
softirq.c
softlockup.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl.c
taskstats.c
time.c
timer.c
tsacct.c
uid16.c
user.c
utsname_sysctl.c
utsname.c
wait.c
workqueue.c