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Ingo Molnar 7355690ead [PATCH] sched: fix SMT scheduler bug 
The SMT scheduler incorrectly skips kernel threads even if they are
runnable (but they are preempted by a higher-prio user-space task which got
SMT-delayed by an even higher-priority task running on a sibling CPU).

Fix this for now by only doing the SMT-nice optimization if the
to-be-delayed task is the only runnable task.  (This should cover most of
the real-life cases anyway.)

This bug has been in the SMT scheduler since 2.6.17 or so, but has only
been noticed now by the active check in the dynticks code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-01 14:53:38 -08:00
..
irq [PATCH] genirq: Mask irqs when migrating them. 2007-02-26 10:34:08 -08:00
power power management: no valid states w/o pm_ops 2007-02-23 14:52:09 -08:00
time [TICK] tick-common: Fix one-shot handling in tick_handle_periodic(). 2007-02-26 11:14:15 -08:00
.gitignore
acct.c [PATCH] kernel: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:42 -08:00
audit.c [PATCH] audit config lockdown 2007-02-17 21:30:12 -05:00
audit.h
auditfilter.c [PATCH] minor update to rule add/delete messages (ver 2) 2007-02-17 21:30:09 -05:00
auditsc.c [PATCH] AUDIT_FD_PAIR 2007-02-17 21:30:15 -05:00
capability.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
compat.c [PATCH] Common compat_sys_sysinfo 2007-02-11 10:51:32 -08:00
configs.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
cpu.c [PATCH] swsusp: Change code ordering in disk.c 2007-02-11 10:51:19 -08:00
cpuset.c [PATCH] mark struct inode_operations const 2 2007-02-12 09:48:46 -08:00
delayacct.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
dma.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00
exec_domain.c
exit.c [PATCH] pid: replace is_orphaned_pgrp with is_current_pgrp_orphaned 2007-02-12 09:48:32 -08:00
extable.c
fork.c [PATCH] hrtimers: namespace and enum cleanup 2007-02-16 08:13:58 -08:00
futex_compat.c
futex.c [PATCH] hrtimers: namespace and enum cleanup 2007-02-16 08:13:58 -08:00
hrtimer.c [PATCH] Add debugging feature /proc/timer_stat 2007-02-16 08:13:59 -08:00
itimer.c [PATCH] hrtimers: prevent possible itimer DoS 2007-02-16 08:13:59 -08:00
kallsyms.c [PATCH] move kallsyms data to .rodata 2006-12-08 08:28:37 -08:00
Kconfig.hz [PATCH] HZ: 300Hz support 2006-12-07 08:39:36 -08:00
Kconfig.preempt
kexec.c Merge branch 'release' of master.kernel.org:/pub/scm/linux/kernel/git/aegl/linux-2.6 2006-12-07 15:39:22 -08:00
kfifo.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
kmod.c Revert "Driver core: let request_module() send a /sys/modules/kmod/-uevent" 2007-02-23 14:54:57 -08:00
kprobes.c [PATCH] kprobes: list all active probes in the system 2007-02-20 17:10:14 -08:00
ksysfs.c
kthread.c [PATCH] Numerous fixes to kernel-doc info in source files. 2007-02-11 10:51:32 -08:00
latency.c [PATCH] severing module.h->sched.h 2006-12-04 02:00:22 -05:00
lockdep_internals.h [PATCH] lockdep: more chains 2006-12-07 08:39:43 -08:00
lockdep_proc.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
lockdep.c [PATCH] fix section mismatch warning in lockdep 2007-03-01 14:53:37 -08:00
Makefile [PATCH] sysctl: move utsname sysctls to their own file 2007-02-14 08:09:58 -08:00
module.c Revert "Driver core: let request_module() send a /sys/modules/kmod/-uevent" 2007-02-23 14:54:57 -08:00
mutex-debug.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
mutex-debug.h
mutex.c [PATCH] lockdep: avoid lockdep warning in md 2006-12-08 08:28:39 -08:00
mutex.h
nsproxy.c Revert "[PATCH] namespaces: fix exit race by splitting exit" 2007-01-30 13:35:18 -08:00
panic.c [PATCH] Add TAINT_USER and ability to set taint flags from userspace 2007-02-11 10:51:29 -08:00
params.c Revert "Driver core: let request_module() send a /sys/modules/kmod/-uevent" 2007-02-23 14:54:57 -08:00
pid.c [PATCH] namespaces: fix task exit disaster 2007-01-30 13:40:36 -08:00
posix-cpu-timers.c [PATCH] posix timers: RCU optimization for clock_gettime() 2007-02-16 08:14:00 -08:00
posix-timers.c [PATCH] hrtimers: add high resolution timer support 2007-02-16 08:13:59 -08:00
printk.c kernel/printk.c: comment fix 2007-02-17 20:10:16 +01:00
profile.c [PATCH] proc: remove useless (and buggy) ->nlink settings 2007-02-11 10:51:32 -08:00
ptrace.c
rcupdate.c [PATCH] rcu: add a prefetch() in rcu_do_batch() 2006-12-07 08:39:40 -08:00
rcutorture.c [PATCH] rcu: rcutorture suspend fix 2006-12-30 10:55:55 -08:00
relay.c [PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers) 2007-03-01 14:53:37 -08:00
resource.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
rtmutex.c [PATCH] hrtimers: namespace and enum cleanup 2007-02-16 08:13:58 -08:00
rtmutex.h
rwsem.c
sched.c [PATCH] sched: fix SMT scheduler bug 2007-03-01 14:53:38 -08:00
seccomp.c
signal.c Merge master.kernel.org:/pub/scm/linux/kernel/git/kyle/parisc-2.6 2007-02-26 12:48:06 -08:00
softirq.c [PATCH] tick-management: dyntick / highres functionality 2007-02-16 08:13:59 -08:00
softlockup.c
spinlock.c [PATCH] lockdep: spin_lock_irqsave_nested() 2006-11-25 13:28:34 -08:00
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c [PATCH] Create compat_sys_migrate_pages 2006-11-03 12:27:59 -08:00
sys.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
sysctl.c [PATCH] fix the SYSCTL=n compilation 2007-03-01 14:53:37 -08:00
taskstats.c [PATCH] taskstats: cleanup reply assembling 2006-12-07 08:39:34 -08:00
time.c [PATCH] Fix multiple conversion bugs in msecs_to_jiffies 2007-02-16 08:13:56 -08:00
timer.c [PATCH] kernel-doc fixes for 2.6.20-git15 (non-drivers) 2007-03-01 14:53:37 -08:00
tsacct.c [PATCH] time: x86_64: split x86_64/kernel/time.c up 2007-02-16 08:14:00 -08:00
uid16.c
user.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
utsname_sysctl.c [PATCH] sysctl: remove insert_at_head from register_sysctl 2007-02-14 08:09:59 -08:00
utsname.c
wait.c
workqueue.c [PATCH] Add debugging feature /proc/timer_stat 2007-02-16 08:13:59 -08:00