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