On Fri, 2014-10-24 at 19:38 -0700, H. Peter Anvin wrote:
> On 10/24/2014 05:22 PM, Andy Lutomirski wrote:
> > Is there any good reason not to use vmalloc for x86_64 stacks?
>
> Additional TLB pressure if anything else.
It seems TLB pressure gets less and less interest these days...
Is it still worth trying to reduce it ?
I was wondering for example why 'hashdist' is not cleared if current
host runs a NUMA enabled kernel, but has a single node.
Something like following maybe ?
diff --git a/Documentation/kernel-parameters.txt
b/Documentation/kernel-parameters.txt
index
7dbe5ec9d9cd08afac13797e2adac291fb703eec..0846ef054b0620a7be0c6f69b1a2f21c78d57d3b
100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1181,7 +1181,7 @@ bytes respectively. Such letter suffixes can also be
entirely omitted.
hashdist= [KNL,NUMA] Large hashes allocated during boot
are distributed across NUMA nodes. Defaults on
for 64-bit NUMA, off otherwise.
- Format: 0 | 1 (for off | on)
+ Format: 0 | 1 | 2 (for off | on if NUMA host | on)
hcl= [IA-64] SGI's Hardware Graph compatibility layer
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index
1a883705a12a8a12410914be93b2ee65807cc423..8aded4c11c8c1cc5778e9ae2b9cd5146070b5b03
100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -668,7 +668,8 @@ static int __init dummy_numa_init(void)
node_set(0, numa_nodes_parsed);
numa_add_memblk(0, 0, PFN_PHYS(max_pfn));
-
+ if (hashdist == HASHDIST_DEFAULT)
+ hashdist = 0;
return 0;
}
--
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