tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too
Subsystems (2)
RFC PATCH v2 1/1 tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too
Hi Frederic and Marcelo,
The only change since RFC v1 [1] is an alternative approach to hopefully resolve the second scenario [2] without disturbing the workload via an interrupt. Any feedback/or testing would be appreciated. Thanks!
[1]: https://lore.kernel.org/lkml/[email protected]/
[2]: https://lore.kernel.org/lkml/20220217163205.GA748087@lothringen/
In the context of the idle task and an adaptive-tick mode/or a nohz_full CPU, quiet_vmstat() can be called: before stopping the idle tick, entering an idle state and on exit. In particular, for the latter case, when the idle task is required to reschedule, the idle tick can remain stopped and the timer expiration time endless i.e., KTIME_MAX. Now, indeed before a nohz_full CPU enters an idle state, CPU-specific vmstat counters should be processed to ensure the respective values have been reset and folded into the zone specific 'vm_stat[]'. That being said, it can only occur when: the idle tick was previously stopped, and reprogramming of the timer is not required.
A customer provided some evidence which indicates that the idle tick was stopped; albeit, CPU-specific vmstat counters still remained populated. Thus one can only assume quiet_vmstat() was not invoked on return to the idle loop.
If I understand correctly, I suspect this divergence might erroneously prevent a reclaim attempt by kswapd. If the number of zone specific free pages are below their per-cpu drift value then zone_page_state_snapshot() is used to compute a more accurate view of the aforementioned statistic. Thus any task blocked on the NUMA node specific pfmemalloc_wait queue will be unable to make significant progress via direct reclaim unless it is killed after being woken up by kswapd (see throttle_direct_reclaim()).
Consider the following theoretical scenario:
1. CPU Y migrated running task A to CPU X that was
in an idle state i.e. waiting for an IRQ - not polling; marked the current task on CPU X to need/or require a reschedule i.e., set TIF_NEED_RESCHED and invoked a reschedule IPI to CPU X (see sched_move_task())
2. CPU X acknowledged the reschedule IPI from CPU Y;
generic idle loop code noticed the TIF_NEED_RESCHED flag against the idle task and attempts to exit of the loop and calls the main scheduler function i.e. __schedule().
Since the idle tick was previously stopped no scheduling-clock tick would occur. So, no deferred timers would be handled
3. Post transition to kernel execution Task A
running on CPU Y, indirectly released a few pages (e.g. see __free_one_page()); CPU Y's 'vm_stat_diff[NR_FREE_PAGES]' was updated and zone specific 'vm_stat[]' update was deferred as per the CPU-specific stat threshold
4. Task A does invoke exit(2) and the kernel does
remove the task from the run-queue; the idle task was selected to execute next since there are no other runnable tasks assigned to the given CPU (see pick_next_task() and pick_next_task_idle())
5. On return to the idle loop since the idle tick
was already stopped and can remain so (see [1] below) e.g. no pending soft IRQs, no attempt is made to zero and fold CPU Y's vmstat counters since reprogramming of the scheduling-clock tick is not required/or needed (see [2])
...
do_idle
{
__current_set_polling()
tick_nohz_idle_enter()
while (!need_resched()) {
local_irq_disable()
...
/* No polling or broadcast event */ cpuidle_idle_call()
{
if (cpuidle_not_available(drv, dev)) {
tick_nohz_idle_stop_tick()
__tick_nohz_idle_stop_tick(this_cpu_ptr(&tick_cpu_sched)) {
int cpu = smp_processor_id()
if (ts->timer_expires_base)
expires = ts->timer_expires
else if (can_stop_idle_tick(cpu, ts))
(1) -------> expires = tick_nohz_next_event(ts, cpu)
else
return
ts->idle_calls++
if (expires > 0LL) {
tick_nohz_stop_tick(ts, cpu) {
if (ts->tick_stopped && (expires == ts->next_tick)) {
(2) -------> if (tick == KTIME_MAX || ts->next_tick ==
hrtimer_get_expires(&ts->sched_timer)) return
}
...
}
So the idea of this patch is to ensure refresh_cpu_vm_stats(false) is called (when it is appropriate) on return to the idle loop when the idle tick was previously stopped too. Additionally, when the scheduling-tick is stopped and a task in kernel-mode, modifies the CPU-specific 'vm_stat_diff[]' and goes to user-mode for a long time.
--- include/linux/tick.h | 9 ++++++++- kernel/time/tick-sched.c | 4 +++- 2 files changed, 11 insertions(+), 2 deletions(-)
include/linux/tick.h +8 -1
@@ -307,8 +307,15 @@ static inline void tick_nohz_task_switch(void)static inline void tick_nohz_user_enter_prepare (void ) { -if (tick_nohz_full_cpu (smp_processor_id ())) +struct tick_sched *ts; + +if (tick_nohz_full_cpu (smp_processor_id ())) { + ts =this_cpu_ptr (&tick_cpu_sched); + +if (ts->tick_stopped) +quiet_vmstat ();rcu_nocb_flush_deferred_wakeup (); + } }#endif
kernel/time/tick-sched.c +3 -1
@@ -891,6 +891,9 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu) ts->do_timer_last =0 ; } +/* Attempt to fold when the idle tick is stopped or not */ +quiet_vmstat (); +/* Skip reprogram of event if its not changed */ if (ts->tick_stopped && (expires == ts->next_tick)) {/* Sanity check: make sure clockevent is actually programmed */
@@ -912,7 +915,6 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)*/ if (!ts->tick_stopped) {calc_load_nohz_start (); -quiet_vmstat (); ts->last_tick =hrtimer_get_expires (&ts->sched_timer); ts->tick_stopped =1 ;
Signature · 1 line
2.34.1
kernel test robot
build bot[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch]
Hi Aaron,
[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on v5.18-rc3]
[also build test ERROR on next-20220422]
[cannot apply to tip/timers/nohz]
[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Aaron-Tomlin/tick-sched-Ensure-quiet_vmstat-is-called-when-the-idle-tick-was-stopped-too/20220422-192320 base: b2d229d4ddb17db541098b83524d901257e93845 config: x86_64-randconfig-a016 (https://download.01.org/0day-ci/archive/20220423/[email protected]/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 5bd87350a5ae429baf8f373cb226a57b62f87280)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/0be2b64445273bddc478567c0846c1046f28995a
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Aaron-Tomlin/tick-sched-Ensure-quiet_vmstat-is-called-when-the-idle-tick-was-stopped-too/20220422-192320 git checkout 0be2b64445273bddc478567c0846c1046f28995a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/media/i2c/ kernel/
If you fix the issue, kindly add following tag as appropriate
All errors (new ones prefixed by >>):
In file included from kernel/cpu.c:13:
In file included from include/linux/sched/isolation.h:6:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
>> include/linux/tick.h:316:4: error: call to undeclared function 'quiet_vmstat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
quiet_vmstat();
^
In file included from kernel/cpu.c:18:
In file included from include/linux/oom.h:11:
In file included from include/linux/mm.h:1719:
>> include/linux/vmstat.h:299:6: error: conflicting types for 'quiet_vmstat'
void quiet_vmstat(void);
^
include/linux/tick.h:316:4: note: previous implicit declaration is here
quiet_vmstat();
^
7 errors generated.
--
In file included from kernel/softirq.c:27:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
5 errors generated.
--
In file included from kernel/irq_work.c:17:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
>> include/linux/tick.h:316:4: error: call to undeclared function 'quiet_vmstat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
quiet_vmstat();
^ 6 errors generated.
--
In file included from kernel/sched/core.c:30:
In file included from include/linux/sched/isolation.h:6:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
kernel/sched/core.c:3518:6: warning: no previous prototype for function 'sched_set_stop_task' [-Wmissing-prototypes]
void sched_set_stop_task(int cpu, struct task_struct *stop)
^
kernel/sched/core.c:3518:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void sched_set_stop_task(int cpu, struct task_struct *stop)
^
static
kernel/sched/core.c:5235:20: warning: no previous prototype for function 'task_sched_runtime' [-Wmissing-prototypes]
unsigned long long task_sched_runtime(struct task_struct *p)
^
kernel/sched/core.c:5235:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
unsigned long long task_sched_runtime(struct task_struct *p)
^
static
kernel/sched/core.c:8952:6: warning: no previous prototype for function 'idle_task_exit' [-Wmissing-prototypes]
void idle_task_exit(void)
^
kernel/sched/core.c:8952:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void idle_task_exit(void)
^
static
kernel/sched/core.c:9187:5: warning: no previous prototype for function 'sched_cpu_activate' [-Wmissing-prototypes]
int sched_cpu_activate(unsigned int cpu)
^
kernel/sched/core.c:9187:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int sched_cpu_activate(unsigned int cpu)
^
static
kernel/sched/core.c:9232:5: warning: no previous prototype for function 'sched_cpu_deactivate' [-Wmissing-prototypes]
int sched_cpu_deactivate(unsigned int cpu)
^
kernel/sched/core.c:9232:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int sched_cpu_deactivate(unsigned int cpu)
^
static
kernel/sched/core.c:9307:5: warning: no previous prototype for function 'sched_cpu_starting' [-Wmissing-prototypes]
int sched_cpu_starting(unsigned int cpu)
^
kernel/sched/core.c:9307:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int sched_cpu_starting(unsigned int cpu)
^
static
kernel/sched/core.c:9328:5: warning: no previous prototype for function 'sched_cpu_wait_empty' [-Wmissing-prototypes]
int sched_cpu_wait_empty(unsigned int cpu)
^
kernel/sched/core.c:9328:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int sched_cpu_wait_empty(unsigned int cpu)
^
static
kernel/sched/core.c:9370:5: warning: no previous prototype for function 'sched_cpu_dying' [-Wmissing-prototypes]
int sched_cpu_dying(unsigned int cpu)
^
kernel/sched/core.c:9370:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int sched_cpu_dying(unsigned int cpu)
^
static
kernel/sched/core.c:9393:13: warning: no previous prototype for function 'sched_init_smp' [-Wmissing-prototypes]
void __init sched_init_smp(void)
^
kernel/sched/core.c:9393:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void __init sched_init_smp(void)
^
static
kernel/sched/core.c:9454:13: warning: no previous prototype for function 'sched_init' [-Wmissing-prototypes]
void __init sched_init(void)
^ kernel/sched/core.c:9454:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init sched_init(void)
^
static
10 warnings and 5 errors generated.
--
In file included from kernel/sched/fair.c:38:
In file included from include/linux/sched/isolation.h:6:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
kernel/sched/fair.c:11137:6: warning: no previous prototype for function 'task_vruntime_update' [-Wmissing-prototypes]
void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
^ kernel/sched/fair.c:11137:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi)
^
static
1 warning and 5 errors generated.
--
In file included from kernel/sched/build_policy.c:33:
In file included from kernel/sched/sched.h:62:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
In file included from kernel/sched/build_policy.c:43:
kernel/sched/rt.c:666:6: warning: no previous prototype for function 'sched_rt_bandwidth_account' [-Wmissing-prototypes]
bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
^ kernel/sched/rt.c:666:1: note: declare 'static' if the function is not intended to be used outside of this translation unit bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
^
static
1 warning and 5 errors generated.
--
In file included from kernel/irq/manage.c:21:
In file included from include/linux/sched/isolation.h:6:
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
ts = this_cpu_ptr(&tick_cpu_sched);
^
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:22: error: use of undeclared identifier 'tick_cpu_sched'
>> include/linux/tick.h:313:6: error: assigning to 'struct tick_sched *' from incompatible type 'void'
ts = this_cpu_ptr(&tick_cpu_sched);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/tick.h:315:9: error: incomplete definition of type 'struct tick_sched'
if (ts->tick_stopped)
~~^
include/linux/tick.h:310:9: note: forward declaration of 'struct tick_sched'
struct tick_sched *ts;
^
>> include/linux/tick.h:316:4: error: call to undeclared function 'quiet_vmstat'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
quiet_vmstat();
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:97:11: warning: array index 3 is past the end of the array (which contains 1 element) [-Warray-bounds]
return (set->sig[3] | set->sig[2] |
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:97:25: warning: array index 2 is past the end of the array (which contains 1 element) [-Warray-bounds]
return (set->sig[3] | set->sig[2] |
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:98:4: warning: array index 1 is past the end of the array (which contains 1 element) [-Warray-bounds]
set->sig[1] | set->sig[0]) == 0;
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:100:11: warning: array index 1 is past the end of the array (which contains 1 element) [-Warray-bounds]
return (set->sig[1] | set->sig[0]) == 0;
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:113:11: warning: array index 3 is past the end of the array (which contains 1 element) [-Warray-bounds]
return (set1->sig[3] == set2->sig[3]) &&
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:113:27: warning: array index 3 is past the end of the array (which contains 1 element) [-Warray-bounds]
return (set1->sig[3] == set2->sig[3]) &&
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^
In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
include/linux/signal.h:114:5: warning: array index 2 is past the end of the array (which contains 1 element) [-Warray-bounds]
(set1->sig[2] == set2->sig[2]) &&
^ ~
arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
unsigned long sig[_NSIG_WORDS];
^ In file included from kernel/irq/manage.c:25:
In file included from kernel/irq/internals.h:486:
In file included from include/linux/debugfs.h:15:
In file included from include/linux/fs.h:33:
In file included from include/linux/percpu-rwsem.h:7:
In file included from include/linux/rcuwait.h:6:
In file included from include/linux/sched/signal.h:6:
..
vim +/tick_cpu_sched +313 include/linux/tick.h
307
308 static inline void tick_nohz_user_enter_prepare(void)
309 {
310 struct tick_sched *ts;
311
312 if (tick_nohz_full_cpu(smp_processor_id())) {
> 313 ts = this_cpu_ptr(&tick_cpu_sched); 314 > 315 if (ts->tick_stopped) > 316 quiet_vmstat();
317 rcu_nocb_flush_deferred_wakeup();
318 }
319 }
320
Signature · 2 lines
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