[PATCH 08/10] mm: serialize access to min_free_kbytes

Peter Zijlstra
2007-08-06T10:48:18Z

[-- Attachment #1: mm-setup_per_zone_pages_min.patch --]
[-- Type: text/plain, Size: 1842 bytes --]

There is a small race between the procfs caller and the memory hotplug caller
of setup_per_zone_pages_min(). Not a big deal, but the next patch will add yet
another caller. Time to close the gap.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
mm/page_alloc.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

Index: linux-2.6-2/mm/page_alloc.c
===================================================================
--- linux-2.6-2.orig/mm/page_alloc.c
+++ linux-2.6-2/mm/page_alloc.c
@@ -101,6 +101,7 @@ static char * const zone_names[MAX_NR_ZO
"Movable",
};

+static DEFINE_SPINLOCK(min_free_lock);
int min_free_kbytes = 1024;

unsigned long __meminitdata nr_kernel_pages;
@@ -3634,12 +3635,12 @@ static void setup_per_zone_lowmem_reserv
}

/**
- * setup_per_zone_pages_min - called when min_free_kbytes changes.
+ * __setup_per_zone_pages_min - called when min_free_kbytes changes.
*
* Ensures that the pages_{min,low,high} values for each zone are set correctly
* with respect to min_free_kbytes.
*/
-void setup_per_zone_pages_min(void)
+static void __setup_per_zone_pages_min(void)
{
unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
unsigned long lowmem_pages = 0;
@@ -3693,6 +3694,15 @@ void setup_per_zone_pages_min(void)
calculate_totalreserve_pages();
}

+void setup_per_zone_pages_min(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&min_free_lock, flags);
+ __setup_per_zone_pages_min();
+ spin_unlock_irqrestore(&min_free_lock, flags);
+}
+
/*
* Initialise min_free_kbytes.
*
@@ -3728,7 +3738,7 @@ static int __init init_per_zone_pages_mi
min_free_kbytes = 128;
if (min_free_kbytes > 65536)
min_free_kbytes = 65536;
- setup_per_zone_pages_min();
+ __setup_per_zone_pages_min();
setup_per_zone_lowmem_reserve();
return 0;
}

--