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.
Signed-off-by: Chris Metcalf <cmetc...@ezchip.com> --- include/linux/vmstat.h | 2 ++ mm/vmstat.c | 10 ++++++++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index c013b8d8e434..34e3b768e432 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -212,6 +212,7 @@ extern void dec_zone_state(struct zone *, enum zone_stat_item); extern void __dec_zone_state(struct zone *, enum zone_stat_item); void quiet_vmstat(void); +bool vmstat_idle(void); void cpu_vm_stats_fold(int cpu); void refresh_zone_stat_thresholds(void); @@ -274,6 +275,7 @@ static inline void refresh_cpu_vm_stats(int cpu) { } 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 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 a9c446353c7e..05fa1f0eefc8 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1431,6 +1431,16 @@ static bool need_update(int cpu) return false; } +/* + * 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) && !need_update(cpu); +} + /* * Shepherd worker thread that checks the -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/