kernel-hacking-2024-linux-s.../kernel
Heiko Carstens 36cd3c9f92 mutex: have non-spinning mutexes on s390 by default
Impact: performance regression fix for s390

The adaptive spinning mutexes will not always do what one would expect on
virtualized architectures like s390. Especially the cpu_relax() loop in
mutex_spin_on_owner might hurt if the mutex holding cpu has been scheduled
away by the hypervisor.

We would end up in a cpu_relax() loop when there is no chance that the
state of the mutex changes until the target cpu has been scheduled again by
the hypervisor.

For that reason we should change the default behaviour to no-spin on s390.

We do have an instruction which allows to yield the current cpu in favour of
a different target cpu. Also we have an instruction which allows us to figure
out if the target cpu is physically backed.

However we need to do some performance tests until we can come up with
a solution that will do the right thing on s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
LKML-Reference: <20090409184834.7a0df7b2@osiris.boeblingen.de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-09 19:28:24 +02:00
..
irq Merge branch 'linus' into irq/threaded 2009-04-06 01:41:22 +02:00
power Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-04-03 15:24:35 -07:00
time Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-26 16:05:42 -07:00
trace Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-07 14:10:10 -07:00
.gitignore
acct.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
async.c async: remove the temporary (2.6.29) "async is off by default" code 2009-03-28 13:05:30 -07:00
audit.c Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
audit.h
audit_tree.c audit: incorrect ref counting in audit tree tag_chunk 2009-04-05 13:48:26 -04:00
auditfilter.c make the e->rule.xxx shorter in kernel auditfilter.c 2009-04-05 13:40:33 -04:00
auditsc.c Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
backtracetest.c
bounds.c
capability.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
cgroup.c memcg: fix OOM killer under memcg 2009-04-02 19:04:55 -07:00
cgroup_debug.c debug cgroup: remove unneeded cgroup_lock 2009-04-02 19:04:54 -07:00
cgroup_freezer.c
compat.c
configs.c
cpu.c cpumask: use set_cpu_active in init/main.c 2009-03-30 22:05:12 +10:30
cpuset.c cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets 2009-04-02 19:04:57 -07:00
cred-internals.h
cred.c
delayacct.c
dma-coherent.c dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy. 2009-01-21 18:51:53 +09:00
dma.c
exec_domain.c Get rid of indirect include of fs_struct.h 2009-03-31 23:00:27 -04:00
exit.c Merge branch 'irq/threaded' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-07 14:07:52 -07:00
extable.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
fork.c Merge branch 'linus' into core/softlockup 2009-04-07 11:15:40 +02:00
freezer.c
futex.c futex: comment requeue key reference semantics 2009-04-02 23:39:53 +02:00
futex_compat.c
hrtimer.c hrtimer: fix rq->lock inversion (again) 2009-03-31 14:52:52 +02:00
hung_task.c softlockup: ensure the task has been switched out once 2009-02-11 11:04:16 +01:00
itimer.c timers: split process wide cpu clocks/timers 2009-02-05 13:04:33 +01:00
kallsyms.c Ksplice: Add functions for walking kallsyms symbols 2009-03-31 13:05:32 +10:30
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c kexec: vmcoreinfo_data[] can become static 2009-04-02 19:05:04 -07:00
kfifo.c
kgdb.c
kmod.c module: create a request_module_nowait() 2009-03-31 13:05:35 +10:30
kprobes.c kprobes: support per-kprobe disabling 2009-04-07 08:31:08 -07:00
ksysfs.c
kthread.c cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL 2009-03-30 22:05:11 +10:30
latencytop.c sched, latencytop: incorporate review feedback from Andrew Morton 2009-02-11 10:18:04 +01:00
lockdep.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
lockdep_internals.h lockdep: get_user_chars() redo 2009-02-14 23:28:22 +01:00
lockdep_proc.c lockstat: warn about disabled lock debugging 2009-02-14 23:28:28 +01:00
lockdep_states.h lockdep: move state bit definitions around 2009-02-14 23:27:59 +01:00
Makefile Merge branch 'linus' into core/softlockup 2009-04-07 11:15:40 +02:00
marker.c
module.c Revert "module: remove the SHF_ALLOC flag on the __versions section." 2009-04-07 17:12:43 +09:30
mutex-debug.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex-debug.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex.c mutex: have non-spinning mutexes on s390 by default 2009-04-09 19:28:24 +02:00
mutex.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
notifier.c
ns_cgroup.c cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups 2009-04-02 19:04:53 -07:00
nsproxy.c
panic.c panic: clean up kernel/panic.c 2009-03-13 11:25:53 +01:00
params.c param: fix charp parameters set via sysfs 2009-03-31 13:05:30 +10:30
pid.c pids: refactor vnr/nr_ns helpers to make them safe 2009-04-02 19:05:02 -07:00
pid_namespace.c signals: zap_pid_ns_process() should use force_sig() 2009-04-02 19:04:58 -07:00
pm_qos_params.c
posix-cpu-timers.c posix timers: fix RLIMIT_CPU && fork() 2009-03-23 20:43:35 +01:00
posix-timers.c [CVE-2009-0029] System call wrappers part 05 2009-01-14 14:15:20 +01:00
printk.c Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 10:23:25 -07:00
profile.c profiling: fix broken profiling regression 2009-02-10 00:50:37 +01:00
ptrace.c Merge branch 'core-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-03 17:35:06 -07:00
rcuclassic.c kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies 2009-04-03 12:23:02 +02:00
rcupdate.c rcu: rcu_barrier VS cpu_hotplug: Ensure callbacks in dead cpu are migrated to online cpu 2009-03-31 00:09:37 +02:00
rcupreempt.c kmemtrace, rcu: fix rcupreempt.c data structure dependencies 2009-04-03 12:23:04 +02:00
rcupreempt_trace.c
rcutorture.c cpumask: convert rcutorture.c 2009-03-30 22:05:16 +10:30
rcutree.c kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
rcutree.h kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
rcutree_trace.c kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
relay.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
res_counter.c
resource.c resources: fix parameter name and kernel-doc 2009-01-15 16:39:38 -08:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
sched_clock.c Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
sched_cpupri.c
sched_cpupri.h cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sched_debug.c sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
sched_fair.c Merge branch 'sched/urgent'; commit 'v2.6.29-rc5' into sched/core 2009-02-15 21:15:16 +01:00
sched_features.h Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
sched_idletask.c
sched_rt.c Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2 2009-03-27 17:28:43 +01:00
sched_stats.h sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
seccomp.c x86-64: seccomp: fix 32/64 syscall hole 2009-03-02 15:41:30 -08:00
semaphore.c
signal.c signals: SI_USER: Masquerade si_pid when crossing pid ns boundary 2009-04-02 19:04:58 -07:00
slow-work.c Document the slow work thread pool 2009-04-03 16:42:35 +01:00
smp.c generic-ipi: eliminate WARN_ON()s during oops/panic 2009-03-13 10:47:34 +01:00
softirq.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
softlockup.c softlockup: decouple hung tasks check from softlockup detection 2009-01-16 14:06:04 +01:00
spinlock.c Allow rwlocks to re-enable interrupts 2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c
stop_machine.c cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sys.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-04-02 21:09:10 -07:00
sys_ni.c [CVE-2009-0029] Make sys_syslog a conditional system call 2009-01-14 14:15:16 +01:00
sysctl.c Merge branch 'core/softlockup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-07 14:11:07 -07:00
sysctl_check.c net: add ARP notify option for devices 2009-02-01 01:04:33 -08:00
taskstats.c
test_kprobes.c
time.c [CVE-2009-0029] System call wrappers part 01 2009-01-14 14:15:18 +01:00
timeconst.pl
timer.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
tracepoint.c tracepoints: dont update zero-sized tracepoint sections 2009-03-18 19:55:00 +01:00
tsacct.c Fix fixpoint divide exception in acct_update_integrals 2009-03-09 08:13:35 -07:00
uid16.c [CVE-2009-0029] System call wrappers part 19 2009-01-14 14:15:26 +01:00
up.c smp_call_function_single(): be slightly less stupid, fix #2 2009-01-12 16:04:37 +01:00
user.c Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
user_namespace.c Fix recursive lock in free_uid()/free_user_ns() 2009-02-27 16:26:21 -08:00
utsname.c
utsname_sysctl.c proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers 2009-04-02 19:05:01 -07:00
wait.c wait: prevent exclusive waiter starvation 2009-02-05 12:56:48 -08:00
workqueue.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00