In commit f01f17d3705b ("mm, vmstat: make quiet_vmstat lighter") the quiet_vmstat() function became asynchronous, in the sense that the vmstat work was still scheduled to run on the core when the function returned. For task isolation, we need a synchronous version of the function that guarantees that the vmstat worker will not run on the core on return from the function. Add a quiet_vmstat_sync() function with that semantic.
Signed-off-by: Chris Metcalf <cmetc...@ezchip.com> --- include/linux/vmstat.h | 2 ++ mm/vmstat.c | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 73fae8c4a5fb..43b2f1c33266 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -190,6 +190,7 @@ 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); +void quiet_vmstat_sync(void); void cpu_vm_stats_fold(int cpu); void refresh_zone_stat_thresholds(void); @@ -251,6 +252,7 @@ static inline void __dec_zone_page_state(struct page *page, 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 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset) { } diff --git a/mm/vmstat.c b/mm/vmstat.c index 084c6725b373..ff569246fcb5 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1469,6 +1469,15 @@ void quiet_vmstat(void) refresh_cpu_vm_stats(false); } +/* + * Synchronously quiet vmstat so the work is guaranteed not to run on return. + */ +void quiet_vmstat_sync(void) +{ + cpumask_set_cpu(smp_processor_id(), cpu_stat_off); + cancel_delayed_work_sync(this_cpu_ptr(&vmstat_work)); + refresh_cpu_vm_stats(false); +} /* * Shepherd worker thread that checks the -- 2.1.2