Peter Zijlstra
4cfafd3082
sched,perf: Fix periodic timers
...
In the below two commits (see Fixes) we have periodic timers that can
stop themselves when they're no longer required, but need to be
(re)-started when their idle condition changes.
Further complications is that we want the timer handler to always do
the forward such that it will always correctly deal with the overruns,
and we do not want to race such that the handler has already decided
to stop, but the (external) restart sees the timer still active and we
end up with a 'lost' timer.
The problem with the current code is that the re-start can come before
the callback does the forward, at which point the forward from the
callback will WARN about forwarding an enqueued timer.
Now, conceptually its easy to detect if you're before or after the fwd
by comparing the expiration time against the current time. Of course,
that's expensive (and racy) because we don't have the current time.
Alternatively one could cache this state inside the timer, but then
everybody pays the overhead of maintaining this extra state, and that
is undesired.
The only other option that I could see is the external timer_active
variable, which I tried to kill before. I would love a nicer interface
for this seemingly simple 'problem' but alas.
Fixes: 272325c482 ("perf: Fix mux_interval hrtimer wreckage")
Fixes: 77a4d1a1b9 ("sched: Cleanup bandwidth timers")
Cc: pjt@google.com
Cc: tglx@linutronix.de
Cc: klamm@yandex-team.ru
Cc: mingo@kernel.org
Cc: bsegall@google.com
Cc: hpa@zytor.com
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150514102311.GX21418@twins.programming.kicks-ass.net
2015-05-18 17:17:42 +02:00
..
bpf
bpf: fix two bugs in verification logic when accessing 'ctx' pointer
2015-04-16 14:08:49 -04:00
configs
debug
debug: prevent entering debug mode on panic/exception.
2015-02-19 12:39:03 -06:00
events
sched,perf: Fix periodic timers
2015-05-18 17:17:42 +02:00
gcov
gcov: fix softlockups
2015-04-17 09:04:08 -04:00
irq
irqchip core change for v4.1 (round 3)
2015-04-11 11:17:28 +02:00
livepatch
Merge branch 'for-4.1/core-noarch' into for-linus
2015-04-13 23:57:20 +02:00
locking
rtmutex: Remove bogus hrtimer_active() check
2015-04-22 17:06:51 +02:00
power
Merge back earlier suspend/hibernate material for v4.1.
2015-04-10 12:01:59 +02:00
printk
Merge branch 'iocb' into for-next
2015-04-11 22:24:41 -04:00
rcu
tick: Nohz: Rework next timer evaluation
2015-04-22 17:06:50 +02:00
sched
sched,perf: Fix periodic timers
2015-05-18 17:17:42 +02:00
time
nohz: Fix !HIGH_RES_TIMERS hang
2015-05-07 16:15:50 +02:00
trace
tracing: remove use of seq_printf return value
2015-04-15 16:35:25 -07:00
.gitignore
acct.c
acct: check FMODE_CAN_WRITE
2015-04-11 22:27:55 -04:00
async.c
audit.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
2014-12-30 10:45:47 -08:00
audit.h
audit: replace getname()/putname() hacks with reference counters
2015-01-23 00:23:58 -05:00
audit_tree.c
fsnotify: unify inode and mount marks handling
2014-12-13 12:42:53 -08:00
audit_watch.c
auditfilter.c
Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit
2015-02-11 20:07:47 -08:00
auditsc.c
Merge branch 'getname2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2015-02-17 15:27:47 -08:00
backtracetest.c
bounds.c
capability.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
cgroup.c
cgroup: remove use of seq_printf return value
2015-04-15 16:35:25 -07:00
cgroup_freezer.c
compat.c
all arches, signal: move restart_block to struct task_struct
2015-02-12 18:54:12 -08:00
configs.c
context_tracking.c
context_tracking: Export context_tracking_user_enter/exit
2015-03-09 15:43:00 +01:00
cpu.c
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-04-14 13:36:04 -07:00
cpu_pm.c
cpuset.c
kernel, cpuset: remove exception for __GFP_THISNODE
2015-04-14 16:49:03 -07:00
crash_dump.c
cred.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
Remove rest of exec domains.
2015-04-12 21:03:31 +02:00
exit.c
Remove execution domain support
2015-04-12 20:58:24 +02:00
extable.c
ftrace/x86/extable: Add is_ftrace_trampoline() function
2014-11-19 15:25:26 -05:00
fork.c
oprofile: reduce mmap_sem hold for mm->exe_file
2015-04-17 09:04:11 -04:00
freezer.c
futex.c
futex: Remove bogus hrtimer_active() check
2015-04-22 17:06:51 +02:00
futex_compat.c
groups.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
hung_task.c
kernel/hung_task.c: change hung_task.c to use for_each_process_thread()
2015-04-15 16:35:22 -07:00
irq_work.c
percpu: Convert remaining __get_cpu_var uses in 3.18-rcX
2014-10-29 11:18:18 -04:00
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
locking/mcs: Better differentiate between MCS variants
2015-01-14 15:07:32 +01:00
Kconfig.preempt
kexec.c
kexec: simplify conditional
2015-02-17 14:34:51 -08:00
kmod.c
usermodehelper: kill the kmod_thread_locker logic
2014-12-10 17:41:17 -08:00
kprobes.c
kprobes: makes kprobes/enabled works correctly for optimized kprobes.
2015-02-13 21:21:42 -08:00
ksysfs.c
kthread.c
latencytop.c
Makefile
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
module-internal.h
module.c
Some clean ups and small fixes, but the biggest change is the addition
2015-04-14 10:49:03 -07:00
module_signing.c
notifier.c
rcu: Make SRCU optional by using CONFIG_SRCU
2015-01-06 11:04:29 -08:00
nsproxy.c
bury struct proc_ns in fs/proc
2014-12-04 14:34:54 -05:00
padata.c
padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks
2015-02-13 21:21:38 -08:00
panic.c
livepatch: kernel: add TAINT_LIVEPATCH
2014-12-22 15:40:48 +01:00
params.c
param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC
2015-01-20 11:38:31 +10:30
pid.c
fork: report pid reservation failure properly
2015-04-17 09:04:06 -04:00
pid_namespace.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2014-12-16 15:53:03 -08:00
profile.c
profile: use %*pb[l] to print bitmaps including cpumasks and nodemasks
2015-02-13 21:21:38 -08:00
ptrace.c
ptrace: ptrace_detach() can no longer race with SIGKILL
2015-04-17 09:04:06 -04:00
range.c
kernel: avoid overflow in cmp_range
2015-01-17 10:02:23 +13:00
reboot.c
kernel/reboot.c: add orderly_reboot for graceful reboot
2015-04-15 16:35:23 -07:00
relay.c
resource.c
kernel/resource.c: remove deprecated __check_region() and friends
2015-04-15 16:35:22 -07:00
seccomp.c
seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO
2015-02-17 14:34:55 -08:00
signal.c
signal: remove warning about using SI_TKILL in rt_[tg]sigqueueinfo
2015-04-17 09:04:06 -04:00
smp.c
smp: Fix error case handling in smp_call_function_*()
2015-04-19 13:19:23 -07:00
smpboot.c
smpboot: Add common code for notification from dying CPU
2015-03-11 13:20:25 -07:00
smpboot.h
softirq.c
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-02-09 15:24:03 -08:00
stacktrace.c
stacktrace: introduce snprint_stack_trace for buffer output
2014-12-13 12:42:48 -08:00
stop_machine.c
sys.c
prctl: avoid using mmap_sem for exe_file serialization
2015-04-17 09:04:07 -04:00
sys_ni.c
kernel: conditionally support non-root users, groups and capabilities
2015-04-15 16:35:22 -07:00
sysctl.c
kernel/sysctl.c: detect overflows when converting to int
2015-04-17 09:04:08 -04:00
sysctl_binary.c
kernel: add panic_on_warn
2014-12-10 17:41:10 -08:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c
netlink: make nlmsg_end() and genlmsg_end() void
2015-01-18 01:03:45 -05:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c
groups: Consolidate the setgroups permission checks
2014-12-05 17:19:27 -06:00
up.c
user-return-notifier.c
user.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2014-12-17 12:31:40 -08:00
user_namespace.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2014-12-17 12:31:40 -08:00
utsname.c
copy address of proc_ns_ops into ns_common
2014-12-04 14:34:47 -05:00
utsname_sysctl.c
watchdog.c
Merge branch 'akpm' (patches from Andrew)
2015-04-14 16:49:17 -07:00
workqueue.c
workqueue: Reorder sysfs code
2015-04-06 11:16:04 -04:00
workqueue_internal.h