[patch -mm 2/7] x86_64: split remaining fake nodes equally

From: David Rientjes
Date: Wed Jan 31 2007 - 10:18:52 EST


Extends the numa=fake x86_64 command-line option to split the remaining
system memory into equal-sized nodes.

For example:
numa=fake=2*512,4* gives two 512M nodes and the remaining system
memory is split into four approximately equal
chunks.

This is beneficial for systems where the exact size of RAM is unknown or
not necessarily relevant, but the granularity with which nodes shall be
allocated is known.

Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
Documentation/x86_64/boot-options.txt | 4 +++-
arch/x86_64/mm/numa.c | 22 ++++++++++++++++++----
2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index 87f4279..01dfec9 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -155,7 +155,9 @@ NUMA
depending on the sizes and coefficients listed. For example:
numa=fake=2*512,1024,4*256
gives two 512M nodes, a 1024M node, and four 256M nodes. The
- remaining system RAM is allocated to an additional node.
+ remaining system RAM is allocated to an additional node. If
+ the last character of CMDLINE is a *, the remaining system RAM
+ is instead divided up equally among its coefficient.

numa=hotadd=percent
Only allow hotadd memory to preallocate page structures upto
diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index a5bda07..6c4b45f 100644
--- a/arch/x86_64/mm/numa.c
+++ b/arch/x86_64/mm/numa.c
@@ -421,11 +421,25 @@ static int __init numa_emulation(unsigned long start_pfn, unsigned long end_pfn)
done:
if (!num_nodes)
return -1;
- /* Fill remainder of system RAM with a final node, if appropriate. */
+ /* Fill remainder of system RAM, if appropriate. */
if (addr < max_addr) {
- setup_node_range(num_nodes, nodes, &addr, max_addr - addr,
- max_addr);
- num_nodes++;
+ switch (*(cmdline - 1)) {
+ case '*':
+ /* Split remaining nodes into coeff chunks */
+ if (coeff <= 0)
+ break;
+ num_nodes += split_nodes_equally(nodes, &addr, max_addr,
+ num_nodes, coeff);
+ break;
+ case ',':
+ /* Do not allocate remaining system RAM */
+ break;
+ default:
+ /* Give one final node */
+ setup_node_range(num_nodes, nodes, &addr,
+ max_addr - addr, max_addr);
+ num_nodes++;
+ }
}
out:
memnode_shift = compute_hash_shift(nodes, num_nodes);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/