[PATCH 07/33] mm: serialize access to min_free_kbytes
From: Peter Zijlstra <hidden>
Date: 2007-10-30 16:22:28
Also in:
linux-mm, lkml
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 <redacted> --- mm/page_alloc.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) Index: linux-2.6/mm/page_alloc.c ===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c@@ -116,6 +116,7 @@ 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;
@@ -4162,12 +4163,12 @@ 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;
@@ -4222,6 +4223,15 @@ 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. *
@@ -4257,7 +4267,7 @@ 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; } --