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1bd04bf6f6
linux/kernel
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Thomas Gleixner 1bd04bf6f6 timer: Remove FIFO "guarantee" 
The FIFO guarantee is only there if two timers are queued into the
same bucket at the same jiffie on the same cpu:

 - The slack value depends on the delta between expiry and enqueue
   time, so the resulting expiry time can be different for timers
   which are queued in different jiffies.

 - Timers which are queued into the secondary array end up after a
   later queued timer which was queued into the primary array due to
   cascading.

 - Timers can end up on different cpus due to the NOHZ target moving
   around. Obviously there is no guarantee of expiry ordering between
   cpus.

So anything which relies on FIFO behaviour of the timer wheel is
broken already.

This is a preparatory patch for converting the timer wheel to hlist
which reduces the memory foot print of the wheel by 50%.

It's a seperate patch so any (unlikely to happen) regression caused by
this can be identified clearly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Cc: George Spelvin <linux@horizon.com>
Link: http://lkml.kernel.org/r/20150526224511.757520403@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 15:18:27 +02:00
..
bpf bpf: fix 64-bit divide 2015-04-27 23:11:49 -04:00
configs x86: Add "make tinyconfig" to configure the tiniest possible kernel 2014-08-08 16:30:24 -07:00
debug debug: prevent entering debug mode on panic/exception. 2015-02-19 12:39:03 -06:00
events Merge branch 'linus' into timers/core 2015-05-19 16:12:32 +02:00
gcov gcov: fix softlockups 2015-04-17 09:04:08 -04:00
irq genirq: Set IRQCHIP_SKIP_SET_WAKE flag for dummy_irq_chip 2015-04-24 20:57:06 +02:00
livepatch Merge branch 'for-4.1/core-noarch' into for-linus 2015-04-13 23:57:20 +02:00
locking Merge branch 'linus' into timers/core 2015-05-19 16:12:32 +02:00
power Merge back earlier suspend/hibernate material for v4.1. 2015-04-10 12:01:59 +02:00
printk TTY/Serial patches for 4.1-rc1 2015-04-21 09:33:10 -07:00
rcu Merge branch 'linus' into timers/core 2015-05-19 16:12:32 +02:00
sched Merge branch 'linus' into timers/core 2015-05-19 16:12:32 +02:00
time timer: Remove FIFO "guarantee" 2015-06-19 15:18:27 +02:00
trace tracing: Make ftrace_print_array_seq compute buf_len 2015-05-06 23:03:23 -04:00
.gitignore
acct.c acct: check FMODE_CAN_WRITE 2015-04-11 22:27:55 -04:00
async.c kernel/async.c: switch to pr_foo() 2014-10-09 22:26:04 -04:00
audit_tree.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
audit_watch.c VFS: audit: d_backing_inode() annotations 2015-04-15 15:06:55 -04:00
audit.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
audit.h Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-04-22 14:49:23 -07:00
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 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
backtracetest.c
bounds.c page-cgroup: get rid of NR_PCG_FLAGS 2014-08-08 15:57:18 -07:00
capability.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
cgroup_freezer.c
cgroup.c cgroup: remove use of seq_printf return value 2015-04-15 16:35:25 -07:00
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_pm.c
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
cpuset.c kernel, cpuset: remove exception for __GFP_THISNODE 2015-04-14 16:49:03 -07:00
crash_dump.c crash_dump: Make is_kdump_kernel() accessible from modules 2014-08-25 15:42:19 -07:00
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 freezer: remove obsolete comments in __thaw_task() 2014-10-21 23:44:20 +02:00
futex_compat.c
futex.c futex: Remove bogus hrtimer_active() check 2015-04-22 17:06:51 +02:00
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 kernel/kallsyms.c: use __seq_open_private() 2014-10-14 02:18:16 +02:00
kcmp.c kcmp: fix standard comparison bug 2014-09-10 15:42:12 -07:00
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: allocate the kexec control page with KEXEC_CONTROL_MEMORY_GFP 2015-04-23 16:52:01 +02:00
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 kernel/kthread.c: partial revert of 81c98869fa ("kthread: ensure locality of task_struct allocations") 2014-10-09 22:25:51 -04:00
latencytop.c
Makefile modsign: change default key details 2015-04-30 09:35:41 -07:00
module_signing.c
module-internal.h
module.c Quentin opened a can of worms by adding extable entry checking to modpost, 2015-04-22 09:49:24 -07:00
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 params: handle quotes properly for values not of form foo="bar". 2015-04-15 13:31:23 +09:30
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
pid.c fork: report pid reservation failure properly 2015-04-17 09:04:06 -04:00
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 VFS: kernel/: d_inode() annotations 2015-04-15 15:06:55 -04:00
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_ni.c kernel: conditionally support non-root users, groups and capabilities 2015-04-15 16:35:22 -07:00
sys.c prctl: avoid using mmap_sem for exe_file serialization 2015-04-17 09:04:07 -04:00
sysctl_binary.c kernel: add panic_on_warn 2014-12-10 17:41:10 -08:00
sysctl.c kernel/sysctl.c: detect overflows when converting to int 2015-04-17 09:04:08 -04:00
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 kernel/test_kprobes.c: use current logging functions 2014-08-08 15:57:18 -07:00
torture.c torture: Address race in module cleanup 2014-09-16 13:41:06 -07:00
tracepoint.c
tsacct.c
uid16.c groups: Consolidate the setgroups permission checks 2014-12-05 17:19:27 -06:00
up.c
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
user-return-notifier.c scheduler: Replace __get_cpu_var with this_cpu_ptr 2014-08-26 13:45:45 -04:00
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
utsname_sysctl.c
utsname.c copy address of proc_ns_ops into ns_common 2014-12-04 14:34:47 -05:00
watchdog.c watchdog: Fix merge 'conflict' 2015-05-18 10:08:29 -07:00
workqueue_internal.h
workqueue.c workqueue: Reorder sysfs code 2015-04-06 11:16:04 -04:00