From: Cyrill Gorcunov <gorcunov@openvz.org>
To: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>
Cc: LMMML <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH -mmotm] mm: init_per_zone_pages_min - get rid of sqrt call on small machines
Date: Wed, 6 May 2009 10:19:53 +0400 [thread overview]
Message-ID: <20090506061953.GA16057@lenovo> (raw)
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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next reply other threads:[~2009-05-06 6:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-06 6:19 Cyrill Gorcunov [this message]
2009-05-06 6:36 ` [PATCH -mmotm] mm: init_per_zone_pages_min - get rid of sqrt call on small machines David Rientjes
2009-05-06 6:44 ` Cyrill Gorcunov
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