linux/kernel
Linus Torvalds 11d4616bd0 futex: revert back to the explicit waiter counting code
Srikar Dronamraju reports that commit b0c29f79ec ("futexes: Avoid
taking the hb->lock if there's nothing to wake up") causes java threads
getting stuck on futexes when runing specjbb on a power7 numa box.

The cause appears to be that the powerpc spinlocks aren't using the same
ticket lock model that we use on x86 (and other) architectures, which in
turn result in the "spin_is_locked()" test in hb_waiters_pending()
occasionally reporting an unlocked spinlock even when there are pending
waiters.

So this reinstates Davidlohr Bueso's original explicit waiter counting
code, which I had convinced Davidlohr to drop in favor of figuring out
the pending waiters by just using the existing state of the spinlock and
the wait queue.

Reported-and-tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Original-code-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-20 22:11:17 -07:00
..
cpu
debug
events perf: Fix hotplug splat 2014-02-27 12:38:03 +01:00
gcov
irq genirq: Include missing header file in irqdomain.c 2014-02-27 13:29:35 +01:00
locking
power
printk printk: fix syslog() overflowing user buffer 2014-02-17 12:24:45 -08:00
rcu
sched sched/clock: Prevent tracing recursion in sched_clock_cpu() 2014-03-11 11:33:48 +01:00
time sched_clock: Prevent callers from seeing half-updated data 2014-02-19 17:07:22 +01:00
trace tracing: Fix array size mismatch in format string 2014-03-20 13:21:05 -04:00
.gitignore
acct.c
async.c
audit_tree.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
audit_watch.c inotify: Fix reporting of cookies for inotify events 2014-02-18 11:17:17 +01:00
audit.c audit: Update kdoc for audit_send_reply and audit_list_rules_send 2014-03-08 15:31:54 -08:00
audit.h audit: Use struct net not pid_t to remember the network namespce to reply in 2014-02-28 04:04:33 -08:00
auditfilter.c audit: Update kdoc for audit_send_reply and audit_list_rules_send 2014-03-08 15:31:54 -08:00
auditsc.c execve: use 'struct filename *' for executable name passing 2014-02-05 12:54:53 -08:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c cgroup: fix a failure path in create_css() 2014-03-18 17:15:36 -04:00
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c
cpuset.c cpuset: fix a race condition in __cpuset_node_allowed_softwall() 2014-02-27 09:39:54 -05:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c
extable.c
fork.c
freezer.c
futex_compat.c
futex.c futex: revert back to the explicit waiter counting code 2014-03-20 22:11:17 -07:00
groups.c
hrtimer.c
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kmod.c execve: use 'struct filename *' for executable name passing 2014-02-05 12:54:53 -08:00
kprobes.c
ksysfs.c
kthread.c
latencytop.c
Makefile
module_signing.c
module-internal.h
module.c
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c
pid.c
posix-cpu-timers.c
posix-timers.c
profile.c mm: fix GFP_THISNODE callers and clarify 2014-03-10 17:26:19 -07:00
ptrace.c
range.c
reboot.c
relay.c
res_counter.c
resource.c
seccomp.c
signal.c
smp.c
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus() 2014-03-11 11:33:47 +01:00
sys_ni.c
sys.c
sysctl_binary.c
sysctl.c
system_certificates.S
system_keyring.c
task_work.c
taskstats.c
test_kprobes.c
time.c
timeconst.bc
timer.c
tracepoint.c tracing: Do not add event files for modules that fail tracepoints 2014-03-03 21:11:05 -05:00
tsacct.c
uid16.c
up.c
user_namespace.c user_namespace.c: Remove duplicated word in comment 2014-02-20 11:58:35 -08:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c
workqueue_internal.h
workqueue.c workqueue: ensure @task is valid across kthread_stop() 2014-02-18 16:35:20 -05:00