1 From: Anton Blanchard <anton@samba.org>
2 Subject: powerpc/mm: Reduce hashtable size when using 64kB pages
3 Date: Fri Feb 13 11:57:30 2009 +0000
6 Git: 13870b657578bcce167978ee93dc02bf54e3beb0
8 powerpc/mm: Reduce hashtable size when using 64kB pages
10 At the moment we size the hashtable based on 4kB pages / 2, even on a
11 64kB kernel. This results in a hashtable that is much larger than it
14 Grab the real page size and size the hashtable based on that
16 Note: This only has effect on non hypervisor machines.
18 Signed-off-by: Anton Blanchard <anton@samba.org>
19 Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
20 Acked-by: Nick Piggin <npiggin@suse.de>
22 diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
23 index 8d5b475..f5bc1b2 100644
24 --- a/arch/powerpc/mm/hash_utils_64.c
25 +++ b/arch/powerpc/mm/hash_utils_64.c
26 @@ -516,7 +516,7 @@ static int __init htab_dt_scan_pftsize(unsigned long node,
28 static unsigned long __init htab_get_table_size(void)
30 - unsigned long mem_size, rnd_mem_size, pteg_count;
31 + unsigned long mem_size, rnd_mem_size, pteg_count, psize;
33 /* If hash size isn't already provided by the platform, we try to
34 * retrieve it from the device-tree. If it's not there neither, we
35 @@ -534,7 +534,8 @@ static unsigned long __init htab_get_table_size(void)
39 - pteg_count = max(rnd_mem_size >> (12 + 1), 1UL << 11);
40 + psize = mmu_psize_defs[mmu_virtual_psize].shift;
41 + pteg_count = max(rnd_mem_size >> (psize + 1), 1UL << 11);
43 return pteg_count << 7;