lkml.org 
[lkml]   [2016]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v13 01/12] 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 d2da8e053210..0d96b6b2079d 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -188,6 +188,7 @@ 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);

@@ -253,6 +254,7 @@ 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 cb2a67bb4158..945af7ab624e 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1483,6 +1483,15 @@ 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: 2016-07-14 23:21    [W:0.128 / U:1.492 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site