On 07.09.22 01:43, Rebecca Mckeever wrote:
On Tue, Sep 06, 2022 at 03:17:46PM +0200, David Hildenbrand wrote:
On 04.09.22 06:21, Rebecca Mckeever wrote:
Add function setup_numa_memblock() for setting up a memory layout with
multiple NUMA nodes in a previously allocated dummy physical memory.
This function can be used in place of setup_memblock() in tests that need
to simulate a NUMA system.
setup_numa_memblock():
- allows for setting up a memory layout by specifying the fraction of
MEM_SIZE in each node
Set CONFIG_NODES_SHIFT to 4 when building with NUMA=1 to allow for up to
16 NUMA nodes.
Signed-off-by: Rebecca Mckeever <remckee0@xxxxxxxxx>
---
.../testing/memblock/scripts/Makefile.include | 2 +-
tools/testing/memblock/tests/common.c | 29 +++++++++++++++++++
tools/testing/memblock/tests/common.h | 4 ++-
3 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/tools/testing/memblock/scripts/Makefile.include b/tools/testing/memblock/scripts/Makefile.include
index aa6d82d56a23..998281723590 100644
--- a/tools/testing/memblock/scripts/Makefile.include
+++ b/tools/testing/memblock/scripts/Makefile.include
@@ -3,7 +3,7 @@
# Simulate CONFIG_NUMA=y
ifeq ($(NUMA), 1)
- CFLAGS += -D CONFIG_NUMA
+ CFLAGS += -D CONFIG_NUMA -D CONFIG_NODES_SHIFT=4
endif
# Use 32 bit physical addresses.
diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
index eec6901081af..b6110df21b2a 100644
--- a/tools/testing/memblock/tests/common.c
+++ b/tools/testing/memblock/tests/common.c
@@ -72,6 +72,35 @@ void setup_memblock(void)
fill_memblock();
}
+/**
+ * setup_numa_memblock:
+ * Set up a memory layout with multiple NUMA nodes in a previously allocated
+ * dummy physical memory.
+ * @nodes: an array containing the denominators of the fractions of MEM_SIZE
+ * contained in each node (e.g., if nodes[0] = SZ_8, node 0 will
+ * contain 1/8th of MEM_SIZE)
+ *
+ * The nids will be set to 0 through NUMA_NODES - 1.
+ */
+void setup_numa_memblock(const phys_addr_t nodes[])
+{
+ phys_addr_t base;
+ int flags;
+
+ reset_memblock_regions();
+ base = (phys_addr_t)memory_block.base;
+ flags = (movable_node_is_enabled()) ? MEMBLOCK_NONE : MEMBLOCK_HOTPLUG;
+
+ for (int i = 0; i < NUMA_NODES; i++) {
+ assert(nodes[i] <= MEM_SIZE && nodes[i] > 0);
I think it would be even easier to get if this would just be a fraction.
E.g., instead of "1/8 * MEM_SIZE" just "1/8". All values have to add up to
1.
... but then we'd have to mess with floats eventually, so I guess this makes
it easier to handle these fractions.
We could use "int" and simply specify the fraction in percent, like
nodes[0] = 50;
nodes[1] = 25;
nodes[2] = 25;
and everything has to add up to 100.
This would still be a float for 1/8th (12.5) and 1/16th (6.25). What if
it was the "percent" of 256 (i.e., 0x100)?
Right, or in something "smaller" like 1/32 th. I don't think we go below
that?
If we don't need more digits, why not in "basis points" (per ten thousand)
-> https://en.wikipedia.org/wiki/Basis_point
nodes[0] = 5000; /* 1/2 */
nodes[1] = 2500; /* 1/4 */
nodes[2] = 1250; /* 1/8 */
nodes[4] = 0625; /* 1/32 */
nodes[5] = 0625;
+ phys_addr_t size = MEM_SIZE / nodes[i];
Hmmm, assuming a single node with "MEM_SIZE", we would get size=1.
For a single node of MEM_SIZE, nodes[0] would be 1.
Shouldn't this be "size = nodes[i]"
?
No, not with the current implementation. The nodes array stores the
denominator of the fraction that will be multiplied by MEM_SIZE to
determine the size of that node (the numerator is always 1). So if the
size of the node should be 1/8 * MEM_SIZE, the nodes array just stores
the 8. I think the name of the array is misleading. Do you have any
suggestions for a better name?
Then I am confused about the
assert(nodes[i] <= MEM_SIZE && nodes[i] > 0);
assertion :)
I think it would really be best to just store the actual fraction
somehow. But maybe just I am confused :)
--
Thanks,
David / dhildenb
