qubes-linux-kernel/patches.suse/SoN-01-mm-setup_per_zone_wmarks.patch

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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH 01/31] mm: serialize access to min_free_kbytes
Patch-mainline: not yet
There is a small race between the procfs caller and the memory hotplug caller
of setup_per_zone_wmarks(). 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>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
---
mm/page_alloc.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -148,6 +148,7 @@ static char * const zone_names[MAX_NR_ZO
"Movable",
};
+static DEFINE_SPINLOCK(min_free_lock);
int min_free_kbytes = 1024;
static unsigned long __meminitdata nr_kernel_pages;
@@ -4609,13 +4610,13 @@ static void setup_per_zone_lowmem_reserv
}
/**
- * setup_per_zone_wmarks - called when min_free_kbytes changes
+ * __setup_per_zone_wmarks - called when min_free_kbytes changes
* or when memory is hot-{added|removed}
*
* Ensures that the watermark[min,low,high] values for each zone are set
* correctly with respect to min_free_kbytes.
*/
-void setup_per_zone_wmarks(void)
+static void __setup_per_zone_wmarks(void)
{
unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
unsigned long lowmem_pages = 0;
@@ -4713,6 +4714,15 @@ static void __init setup_per_zone_inacti
calculate_zone_inactive_ratio(zone);
}
+void setup_per_zone_wmarks(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&min_free_lock, flags);
+ __setup_per_zone_wmarks();
+ spin_unlock_irqrestore(&min_free_lock, flags);
+}
+
/*
* Initialise min_free_kbytes.
*
@@ -4748,7 +4758,7 @@ static int __init init_per_zone_wmark_mi
min_free_kbytes = 128;
if (min_free_kbytes > 65536)
min_free_kbytes = 65536;
- setup_per_zone_wmarks();
+ __setup_per_zone_wmarks();
setup_per_zone_lowmem_reserve();
setup_per_zone_inactive_ratio();
return 0;