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Subject[PATCH -mmotm] mm: init_per_zone_pages_min - get rid of sqrt call on small machines
For small machines we may eliminate call for int_sqrt
by using precaulculated value.

CC: David Rientjes <rientjes@google.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
mm/page_alloc.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

Index: linux-2.6.git/mm/page_alloc.c
=====================================================================
--- linux-2.6.git.orig/mm/page_alloc.c
+++ linux-2.6.git/mm/page_alloc.c
@@ -4610,11 +4610,15 @@ static int __init init_per_zone_pages_mi

lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);

- min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
- if (min_free_kbytes < 128)
+ /* for small values we may eliminate sqrt operation completely */
+ if (lowmem_kbytes < 1024)
min_free_kbytes = 128;
- if (min_free_kbytes > 65536)
- min_free_kbytes = 65536;
+ else {
+ min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
+ if (min_free_kbytes > 65536)
+ min_free_kbytes = 65536;
+ }
+
setup_per_zone_pages_min();
setup_per_zone_lowmem_reserve();
setup_per_zone_inactive_ratio();


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