Messages in this thread Patch in this message | | | From | Chris Metcalf <> | Subject | [PATCH v12 02/13] vmstat: add vmstat_idle function | Date | Tue, 5 Apr 2016 13:38:31 -0400 |
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This function checks to see if a vmstat worker is not running, and the vmstat diffs don't require an update. The function is called from the task-isolation code to see if we need to actually do some work to quiet vmstat.
Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> --- include/linux/vmstat.h | 2 ++ mm/vmstat.c | 12 ++++++++++++ 2 files changed, 14 insertions(+)
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 43b2f1c33266..504ebd1fdf33 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -191,6 +191,7 @@ extern void __dec_zone_state(struct zone *, enum zone_stat_item); void quiet_vmstat(void); void quiet_vmstat_sync(void); +bool vmstat_idle(void); void cpu_vm_stats_fold(int cpu); void refresh_zone_stat_thresholds(void); @@ -253,6 +254,7 @@ static inline void refresh_zone_stat_thresholds(void) { } static inline void cpu_vm_stats_fold(int cpu) { } static inline void quiet_vmstat(void) { } static inline void quiet_vmstat_sync(void) { } +static inline bool vmstat_idle(void) { return true; } static inline void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset) { } diff --git a/mm/vmstat.c b/mm/vmstat.c index 7a1cfe383349..fa34ea480ac0 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1469,6 +1469,18 @@ void quiet_vmstat_sync(void) } /* + * Report on whether vmstat processing is quiesced on the core currently: + * no vmstat worker running and no vmstat updates to perform. + */ +bool vmstat_idle(void) +{ + int cpu = smp_processor_id(); + return cpumask_test_cpu(cpu, cpu_stat_off) && + !delayed_work_pending(this_cpu_ptr(&vmstat_work)) && + !need_update(cpu); +} + +/* * Shepherd worker thread that checks the * differentials of processors that have their worker * threads for vm statistics updates disabled because of -- 2.7.2
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