lkml.org 
[lkml]   [2016]   [Aug]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v15 01/13] vmstat: add quiet_vmstat_sync function
    Date
    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 <cmetcalf@mellanox.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 613771909b6e..fab62aa74079 100644
    --- a/include/linux/vmstat.h
    +++ b/include/linux/vmstat.h
    @@ -234,6 +234,7 @@ extern void __dec_zone_state(struct zone *, enum zone_stat_item);
    extern void __dec_node_state(struct pglist_data *, enum node_stat_item);

    void quiet_vmstat(void);
    +void quiet_vmstat_sync(void);
    void cpu_vm_stats_fold(int cpu);
    void refresh_zone_stat_thresholds(void);

    @@ -336,6 +337,7 @@ static inline void __dec_node_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 89cec42d19ff..57fc29750da6 100644
    --- a/mm/vmstat.c
    +++ b/mm/vmstat.c
    @@ -1754,6 +1754,15 @@ void quiet_vmstat(void)
    }

    /*
    + * Synchronously quiet vmstat so the work is guaranteed not to run on return.
    + */
    +void quiet_vmstat_sync(void)
    +{
    + cancel_delayed_work_sync(this_cpu_ptr(&vmstat_work));
    + refresh_cpu_vm_stats(false);
    +}
    +
    +/*
    * Shepherd worker thread that checks the
    * differentials of processors that have their worker
    * threads for vm statistics updates disabled because of
    --
    2.7.2
    \
     
     \ /
      Last update: 2016-09-17 09:57    [W:4.080 / U:0.180 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site