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James Hogan 3a90368866 clockevents: Retry programming min delta up to 10 times 
When CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=n, the call path
hrtimer_reprogram -> clockevents_program_event ->
clockevents_program_min_delta will not retry if the clock event driver
returns -ETIME.

If the driver could not satisfy the program_min_delta for any reason, the
lack of a retry means the CPU may not receive a tick interrupt, potentially
until the counter does a full period. This leads to rcu_sched timeout
messages as the stalled CPU is detected by other CPUs, and other issues if
the CPU is holding locks or other resources at the point at which it
stalls.

There have been a couple of observed mechanisms through which a clock event
driver could not satisfy the requested min_delta and return -ETIME.

With the MIPS GIC driver, the shared execution resource within MT cores
means inconventient latency due to execution of instructions from other
hardware threads in the core, within gic_next_event, can result in an event
being set in the past.

Additionally under virtualisation it is possible to get unexpected latency
during a clockevent device's set_next_event() callback which can make it
return -ETIME even for a delta based on min_delta_ns.

It isn't appropriate to use MIN_ADJUST in the virtualisation case as
occasional hypervisor induced high latency will cause min_delta_ns to
quickly increase to the maximum.

Instead, borrow the retry pattern from the MIN_ADJUST case, but without
making adjustments. Retry up to 10 times, each time increasing the
attempted delta by min_delta, before giving up.

[ Matt: Reworked the loop and made retry increase the delta. ]

Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Martin Schwidefsky" <schwidefsky@de.ibm.com>
Cc: James Hogan <james.hogan@mips.com>
Link: https://lkml.kernel.org/r/1508422643-6075-1-git-send-email-matt.redfearn@mips.com
 		2018-10-29 11:10:38 +08:00
..
bpf bpf: 32-bit RSH verification must truncate input before the ALU op 2018-10-10 08:54:22 +02:00
cgroup cgroup: Fix dom_cgrp propagation when enabling threaded mode 2018-10-18 09:16:24 +02:00
configs ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES. 2017-08-22 18:43:23 -07:00
debug kdb: make "mdr" command repeat 2018-05-30 07:52:41 +02:00
events perf/core: Add sanity check to deal with pinned event failure 2018-10-13 09:27:21 +02:00
gcov License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq genirq: Make force irq threading setup more robust 2018-08-09 12:16:38 +02:00
livepatch livepatch: Validate module/old func name length 2018-09-09 19:55:58 +02:00
locking locking/rtmutex: Allow specifying a subclass for nested locking 2018-09-05 09:26:29 +02:00
power PM / sleep: wakeup: Fix build error caused by missing SRCU support 2018-09-09 19:55:58 +02:00
printk printk/tracing: Do not trace printk_nmi_enter() 2018-09-09 19:55:57 +02:00
rcu rcu: Call touch_nmi_watchdog() while printing stall warnings 2018-05-30 07:52:39 +02:00
sched cpufreq: Move gov_attr_* macros to cpufreq.h 2018-10-29 11:10:38 +08:00
time clockevents: Retry programming min delta up to 10 times 2018-10-29 11:10:38 +08:00
trace ring-buffer: Allow for rescheduling when removing pages 2018-09-29 03:06:04 -07:00
.gitignore
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Kconfig.freezer
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Kconfig.hz
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Kconfig.locks
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Kconfig.preempt
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Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
acct.c kernel/acct.c: fix the acct->needcheck check in check_free_space() 2018-01-10 09:31:17 +01:00
async.c kernel/async.c: revert "async: simplify lowest_in_progress()" 2018-02-16 20:23:05 +01:00
audit.c audit: return on memory error to avoid null pointer dereference 2018-05-30 07:52:39 +02:00
audit.h ipc: mqueue: Replace timespec with timespec64 2017-09-03 20:21:24 -04:00
audit_fsnotify.c Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2017-05-03 11:05:15 -07:00
audit_tree.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_watch.c audit: fix use-after-free in audit_add_watch 2018-09-26 08:38:09 +02:00
auditfilter.c audit: allow not equal op for audit by executable 2018-08-03 07:50:39 +02:00
auditsc.c audit: fix potential null dereference 'context->module.name' 2018-08-06 16:20:49 +02:00
backtracetest.c
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bounds.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
capability.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.c compat: fix 4-byte infoleak via uninitialized struct field 2018-05-16 10:10:26 +02:00
configs.c
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context_tracking.c
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cpu.c cpu/hotplug: Prevent state corruption on error rollback 2018-09-19 22:43:36 +02:00
cpu_pm.c PM / CPU: replace raw_notifier with atomic_notifier 2017-07-31 13:09:49 +02:00
crash_core.c kdump: write correct address of mem_section into vmcoreinfo 2018-01-17 09:45:27 +01:00
crash_dump.c
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cred.c doc: ReSTify credentials.txt 2017-05-18 10:30:19 -06:00
delayacct.c delayacct: Use raw_spinlocks 2018-08-03 07:50:38 +02:00
dma.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
elfcore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exec_domain.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exit.c kernel/exit.c: export abort() to modules 2018-02-13 10:19:49 +01:00
extable.c extable: Enable RCU if it is not watching in kernel_text_address() 2017-09-23 16:50:20 -04:00
fork.c fork: don't copy inconsistent signal handler state to child 2018-09-15 09:45:27 +02:00
freezer.c
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futex.c futex: Fix OWNER_DEAD fixup 2018-02-03 17:38:47 +01:00
futex_compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
groups.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-20 10:10:18 +01:00
hung_task.c kernel/hung_task.c: show all hung tasks before panic 2018-08-03 07:50:23 +02:00
irq_work.c
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jump_label.c jump_label: Invoke jump_label_test() via early_initcall() 2017-12-14 09:53:13 +01:00
kallsyms.c kernel/kallsyms.c: replace all_var with IS_ENABLED(CONFIG_KALLSYMS_ALL) 2017-07-10 16:32:34 -07:00
kcmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kcov.c kcov: ensure irq code sees a valid area 2018-08-03 07:50:22 +02:00
kexec.c kdump: protect vmcoreinfo data under the crash memory 2017-07-12 16:26:00 -07:00
kexec_core.c x86/mm, kexec: Allow kexec to be used with SME 2017-07-18 11:38:04 +02:00
kexec_file.c kexec_file: adjust declaration of kexec_purgatory 2017-07-12 16:26:02 -07:00
kexec_internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmod.c kmod: move #ifdef CONFIG_MODULES wrapper to Makefile 2017-09-08 18:26:51 -07:00
kprobes.c kprobes: Make list and blacklist root user read only 2018-09-05 09:26:41 +02:00
ksysfs.c kexec: move vmcoreinfo out of the kernel's .bss section 2017-07-12 16:25:59 -07:00
kthread.c kthread, tracing: Don't expose half-written comm when creating kthreads 2018-08-03 07:50:21 +02:00
latencytop.c sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h> 2017-03-02 08:42:39 +01:00
memremap.c mm: disallow mappings that conflict for devm_memremap_pages() 2018-10-20 09:48:53 +02:00
module-internal.h
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module.c module: exclude SHN_UNDEF symbols from kallsyms api 2018-10-03 17:00:53 -07:00
module_signing.c
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notifier.c kernel/notifier.c: simplify expression 2017-02-24 17:46:56 -08:00
nsproxy.c perf: Add PERF_RECORD_NAMESPACES to include namespaces related info 2017-03-13 15:57:41 -03:00
padata.c padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata() 2017-05-26 10:10:37 +02:00
panic.c locking/refcounts, x86/asm: Implement fast refcount overflow protection 2017-08-17 10:40:26 +02:00
params.c kernel/params.c: improve STANDARD_PARAM_DEF readability 2017-10-03 17:54:26 -07:00
pid.c pids: make task_tgid_nr_ns() safe 2017-08-21 12:47:31 -07:00
pid_namespace.c userns,pidns: Verify the userns for new pid namespaces 2017-07-20 07:43:58 -05:00
profile.c sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h> 2017-03-02 08:42:39 +01:00
ptrace.c signal: Remove kernel interal si_code magic 2017-07-24 14:30:28 -05:00
range.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot.c
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relay.c kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE 2018-05-30 07:52:00 +02:00
resource.c resource: fix integer overflow at reallocation 2018-04-24 09:36:22 +02:00
seccomp.c seccomp: Move speculation migitation control to arch code 2018-05-22 18:54:04 +02:00
signal.c sched/core: Introduce set_special_state() 2018-06-21 04:02:54 +09:00
smp.c cpu/hotplug: Fix SMT supported evaluation 2018-08-15 18:13:00 +02:00
smpboot.c watchdog/core, powerpc: Lock cpus across reconfiguration 2017-10-04 10:53:54 +02:00
smpboot.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
softirq.c Mark HI and TASKLET softirq synchronous 2018-08-15 18:12:47 +02:00
stacktrace.c stacktrace/x86: add function for detecting reliable stack traces 2017-03-08 09:18:02 +01:00
stop_machine.c stop_machine: Atomically queue and wake stopper threads 2018-09-05 09:26:36 +02:00
sys.c sys: don't hold uts_sem while accessing userspace memory 2018-09-09 19:56:00 +02:00
sys_ni.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sysctl.c kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
sysctl_binary.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
task_work.c locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-25 14:26:21 +01:00
taskstats.c taskstats: add e/u/stime for TGID command 2017-05-08 17:15:12 -07:00
test_kprobes.c
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torture.c torture: Fix typo suppressing CPU-hotplug statistics 2017-07-25 13:04:45 -07:00
tracepoint.c tracepoint: Do not warn on ENOMEM 2018-05-09 09:51:50 +02:00
tsacct.c sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h> 2017-03-02 08:42:39 +01:00
ucount.c ucount: Remove the atomicity from ucount->count 2017-03-06 15:26:37 -06:00
uid16.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-20 10:10:18 +01:00
umh.c kmod: split out umh code into its own file 2017-09-08 18:26:50 -07:00
up.c smp: Avoid using two cache lines for struct call_single_data 2017-08-29 15:14:38 +02:00
user-return-notifier.c
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user.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h> 2017-03-02 08:42:29 +01:00
user_namespace.c userns: move user access out of the mutex 2018-09-09 19:56:00 +02:00
utsname.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
utsname_sysctl.c sys: don't hold uts_sem while accessing userspace memory 2018-09-09 19:56:00 +02:00
watchdog.c watchdog: Mark watchdog touch functions as notrace 2018-09-05 09:26:42 +02:00
watchdog_hld.c watchdog: Mark watchdog touch functions as notrace 2018-09-05 09:26:42 +02:00
workqueue.c watchdog: Mark watchdog touch functions as notrace 2018-09-05 09:26:42 +02:00
workqueue_internal.h Merge branch 'for-4.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2017-11-06 12:26:49 -08:00