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Peter Zijlstra 31656519e1 sched, x86: clean up hrtick implementation 
random uvesafb failures were reported against Gentoo:

  http://bugs.gentoo.org/show_bug.cgi?id=222799

and Mihai Moldovan bisected it back to:

> 8f4d37ec07 is first bad commit
> commit 8f4d37ec07
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date:   Fri Jan 25 21:08:29 2008 +0100
>
>    sched: high-res preemption tick

Linus suspected it to be hrtick + vm86 interaction and observed:

> Btw, Peter, Ingo: I think that commit is doing bad things. They aren't
> _incorrect_ per se, but they are definitely bad.
>
> Why?
>
> Using random _TIF_WORK_MASK flags is really impolite for doing
> "scheduling" work. There's a reason that arch/x86/kernel/entry_32.S
> special-cases the _TIF_NEED_RESCHED flag: we don't want to exit out of
> vm86 mode unnecessarily.
>
> See the "work_notifysig_v86" label, and how it does that
> "save_v86_state()" thing etc etc.

Right, I never liked having to fiddle with those TIF flags. Initially I
needed it because the hrtimer base lock could not nest in the rq lock.
That however is fixed these days.

Currently the only reason left to fiddle with the TIF flags is remote
wakeups. We cannot program a remote cpu's hrtimer. I've been thinking
about using the new and improved IPI function call stuff to implement
hrtimer_start_on().

However that does require that smp_call_function_single(.wait=0) works
from interrupt context - /me looks at the latest series from Jens - Yes
that does seem to be supported, good.

Here's a stab at cleaning this stuff up ...

Mihai reported test success as well.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-20 10:37:28 +02:00
..
irq genirq: remove extraneous checks in manage.c 2008-07-10 07:01:13 +02:00
power Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2008-07-16 17:25:46 -07:00
time Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
trace Merge branch 'tracing/ftrace' into auto-ftrace-next 2008-07-14 15:58:35 +02:00
.gitignore
acct.c
audit_tree.c [PATCH] list_for_each_rcu must die: audit 2008-05-17 03:30:23 -04:00
audit.c [PATCH] remove useless argument type in audit_filter_user() 2008-06-24 23:36:35 -04:00
audit.h [PATCH 1/2] audit: move extern declarations to audit.h 2008-04-28 06:28:04 -04:00
auditfilter.c [PATCH] remove useless argument type in audit_filter_user() 2008-06-24 23:36:35 -04:00
auditsc.c [PATCH] new predicate - AUDIT_FILETYPE 2008-04-28 06:28:37 -04:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c security: filesystem capabilities: fix fragile setuid fixup code 2008-07-04 10:40:08 -07:00
cgroup_debug.c CGroup API files: move "releasable" to cgroup_debug subsystem 2008-04-29 08:06:09 -07:00
cgroup.c cgroups: remove node_ prefix_from ns subsystem 2008-05-24 09:56:14 -07:00
compat.c ntp: support for TAI 2008-05-01 08:03:59 -07:00
configs.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
cpu.c force offline the processor during hot-removal 2008-07-16 23:27:01 +02:00
cpuset.c Merge commit 'v2.6.26' into sched/devel 2008-07-14 12:19:19 +02:00
delayacct.c
dma.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
exec_domain.c
exit.c fix dangling zombie when new parent ignores children 2008-07-16 18:02:34 -07:00
extable.c
fork.c ptrace children revamp 2008-07-16 18:02:33 -07:00
futex_compat.c
futex.c futexes: fix fault handling in futex_lock_pi 2008-06-23 13:31:15 +02:00
hrtimer.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
itimer.c
kallsyms.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
Kconfig.hz sched, x86: clean up hrtick implementation 2008-07-20 10:37:28 +02:00
Kconfig.preempt
kexec.c kexec: make extended crashkernel= syntax less confusing 2008-05-01 08:04:00 -07:00
kfifo.c
kgdb.c kgdb: sparse fix 2008-06-24 10:52:55 -05:00
kmod.c [PATCH] split linux/file.h 2008-05-01 13:08:16 -04:00
kprobes.c kernel/kprobes.c: Made kprobe_blacklist static. 2008-07-10 10:13:51 -07:00
ksysfs.c
kthread.c Freezer: Introduce PF_FREEZER_NOSIG 2008-07-16 23:27:03 +02:00
latencytop.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep_internals.h lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep_proc.c lockdep: add lock_class information to lock_chain and output it 2008-06-24 01:28:20 +02:00
lockdep.c Merge branch 'core/locking' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-14 14:55:13 -07:00
Makefile Revert parts of "ftrace: do not trace scheduler functions" 2008-07-18 08:59:24 +02:00
marker.c Markers - remove extra format argument 2008-05-23 22:25:27 +02:00
module.c modules: proper cleanup of kobject without CONFIG_SYSFS 2008-05-23 13:09:33 +10:00
mutex-debug.c mutex-debug: check mutex magic before owner 2008-05-16 16:53:35 +02:00
mutex-debug.h
mutex.c __mutex_lock_common: use signal_pending_state() 2008-06-10 11:45:09 +02:00
mutex.h
notifier.c ipc: re-enable msgmni automatic recomputing msgmni if set to negative 2008-04-29 08:06:13 -07:00
ns_cgroup.c cgroups: kernel/ns_cgroup.c should #include <linux/nsproxy.h> 2008-04-29 08:06:07 -07:00
nsproxy.c ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC) 2008-04-29 08:06:14 -07:00
panic.c Taint kernel after WARN_ON(condition) 2008-04-29 08:05:59 -07:00
params.c
pid_namespace.c pidns: make pid->level and pid_ns->level unsigned 2008-04-30 08:29:49 -07:00
pid.c rcu: split list.h and move rcu-protected lists into rculist.h 2008-05-19 10:01:37 +02:00
pm_qos_params.c pm_qos_params: BKL pushdown 2008-07-02 15:06:24 -06:00
posix-cpu-timers.c posix-timers: print RT watchdog message 2008-05-24 18:49:22 +02:00
posix-timers.c signals: join send_sigqueue() with send_group_sigqueue() 2008-04-30 08:29:36 -07:00
printk.c Merge branch 'core/printk' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-14 15:27:43 -07:00
profile.c on_each_cpu(): kill unused 'retry' parameter 2008-06-26 11:24:38 +02:00
ptrace.c ptrace children revamp 2008-07-16 18:02:33 -07:00
rcuclassic.c Merge branch 'core/rcu' into core/rcu-for-linus 2008-07-15 21:10:12 +02:00
rcupdate.c Merge branch 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-15 14:12:03 -07:00
rcupreempt_trace.c rcu: remove duplicated include in kernel/rcupreempt_trace.c 2008-05-19 10:03:39 +02:00
rcupreempt.c Merge branch 'core/rcu' into core/rcu-for-linus 2008-07-15 21:10:12 +02:00
rcutorture.c rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers) 2008-06-26 09:24:33 +02:00
relay.c splice: fix sendfile() issue with relay 2008-05-28 14:49:27 +02:00
res_counter.c memcgroup: add the max_usage member on the res_counter 2008-04-29 08:06:10 -07:00
resource.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c Merge branch 'sched/clock' into sched/devel 2008-07-14 12:19:13 +02:00
sched_cpupri.c sched: use a 2-d bitmap for searching lowest-pri CPU 2008-06-06 15:19:28 +02:00
sched_cpupri.h sched: fix the cpuprio count really 2008-06-06 15:19:44 +02:00
sched_debug.c sched: add full schedstats to /proc/sched_debug 2008-06-27 14:31:31 +02:00
sched_fair.c sched, x86: clean up hrtick implementation 2008-07-20 10:37:28 +02:00
sched_features.h sched: bias effective_load() error towards failing wake_affine(). 2008-06-27 14:31:47 +02:00
sched_idletask.c sched: make rt_sched_class, idle_sched_class static 2008-05-05 23:56:17 +02:00
sched_rt.c sched: fix warning in inc_rt_tasks() to not declare variable 'rq' if it's not needed 2008-07-18 13:56:03 +02:00
sched_stats.h sched: fix accounting in task delay accounting & migration 2008-07-04 12:50:23 +02:00
sched.c sched, x86: clean up hrtick implementation 2008-07-20 10:37:28 +02:00
seccomp.c
semaphore.c mmiotrace broken in linux-next (8-bit writes only) 2008-07-01 10:14:06 +02:00
signal.c posix timers: discard SI_TIMER signals on exec 2008-05-26 10:37:07 -07:00
smp.c generic ipi function calls: wait on alloc failure fallback 2008-07-15 14:12:20 -07:00
softirq.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
softlockup.c softlockup: print a module list on being stuck 2008-07-05 08:51:24 +02:00
spinlock.c ftrace: lockdep notrace annotations 2008-05-23 20:39:40 +02:00
srcu.c
stacktrace.c stacktrace: fix modular build, export print_stack_trace and save_stack_trace 2008-06-30 09:20:55 +02:00
stop_machine.c sched: add new API sched_setscheduler_nocheck: add a flag to control access checks 2008-06-23 22:57:56 +02:00
sys_ni.c
sys.c sys_prctl(): fix return of uninitialized value 2008-05-24 09:56:13 -07:00
sysctl_check.c
sysctl.c Merge branch 'core/rcu' into core/rcu-for-linus 2008-07-15 21:10:12 +02:00
taskstats.c Use find_task_by_vpid in taskstats 2008-04-30 08:29:48 -07:00
test_kprobes.c
time.c Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timer.c Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-07-14 16:06:58 -07:00
tsacct.c
uid16.c
user_namespace.c eCryptfs: make key module subsystem respect namespaces 2008-04-29 08:06:07 -07:00
user.c alloc_uid: cleanup 2008-04-30 08:29:53 -07:00
utsname_sysctl.c
utsname.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
wait.c
workqueue.c Christoph has moved 2008-07-04 10:40:04 -07:00