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authorDavid Rientjes <rientjes@google.com>2010-02-15 13:43:30 -0800
committerH. Peter Anvin <hpa@zytor.com>2010-02-15 14:34:10 -0800
commit8df5bb34defd685fe86f60746bbf3d47d1c6f033 (patch)
treef2561781a9e493b297a3872b03ff6e4a23a5576c /arch/x86/mm
parent68fd111e02b979876359c7b471a8bcbca0628b75 (diff)
downloadop-kernel-dev-8df5bb34defd685fe86f60746bbf3d47d1c6f033.zip
op-kernel-dev-8df5bb34defd685fe86f60746bbf3d47d1c6f033.tar.gz
x86, numa: Add fixed node size option for numa emulation
numa=fake=N specifies the number of fake nodes, N, to partition the system into and then allocates them by interleaving over physical nodes. This requires knowledge of the system capacity when attempting to allocate nodes of a certain size: either very large nodes to benchmark scalability of code that operates on individual nodes, or very small nodes to find bugs in the VM. This patch introduces numa=fake=<size>[MG] so it is possible to specify the size of each node to allocate. When used, nodes of the size specified will be allocated and interleaved over the set of physical nodes. FAKE_NODE_MIN_SIZE was also moved to the more-appropriate include/asm/numa_64.h. Signed-off-by: David Rientjes <rientjes@google.com> LKML-Reference: <alpine.DEB.2.00.1002151342510.26927@chino.kir.corp.google.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/numa_64.c117
1 files changed, 109 insertions, 8 deletions
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 2ecbe0c..c47c78b 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -502,6 +502,102 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
}
/*
+ * Returns the end address of a node so that there is at least `size' amount of
+ * non-reserved memory or `max_addr' is reached.
+ */
+static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
+{
+ u64 end = start + size;
+
+ while (end - start - e820_hole_size(start, end) < size) {
+ end += FAKE_NODE_MIN_SIZE;
+ if (end > max_addr) {
+ end = max_addr;
+ break;
+ }
+ }
+ return end;
+}
+
+/*
+ * Sets up fake nodes of `size' interleaved over physical nodes ranging from
+ * `addr' to `max_addr'. The return value is the number of nodes allocated.
+ */
+static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
+{
+ nodemask_t physnode_mask = NODE_MASK_NONE;
+ u64 min_size;
+ int ret = 0;
+ int i;
+
+ if (!size)
+ return -1;
+ /*
+ * The limit on emulated nodes is MAX_NUMNODES, so the size per node is
+ * increased accordingly if the requested size is too small. This
+ * creates a uniform distribution of node sizes across the entire
+ * machine (but not necessarily over physical nodes).
+ */
+ min_size = (max_addr - addr - e820_hole_size(addr, max_addr)) /
+ MAX_NUMNODES;
+ min_size = max(min_size, FAKE_NODE_MIN_SIZE);
+ if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
+ min_size = (min_size + FAKE_NODE_MIN_SIZE) &
+ FAKE_NODE_MIN_HASH_MASK;
+ if (size < min_size) {
+ pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
+ size >> 20, min_size >> 20);
+ size = min_size;
+ }
+ size &= FAKE_NODE_MIN_HASH_MASK;
+
+ for (i = 0; i < MAX_NUMNODES; i++)
+ if (physnodes[i].start != physnodes[i].end)
+ node_set(i, physnode_mask);
+ /*
+ * Fill physical nodes with fake nodes of size until there is no memory
+ * left on any of them.
+ */
+ while (nodes_weight(physnode_mask)) {
+ for_each_node_mask(i, physnode_mask) {
+ u64 dma32_end = MAX_DMA32_PFN << PAGE_SHIFT;
+ u64 end;
+
+ end = find_end_of_node(physnodes[i].start,
+ physnodes[i].end, size);
+ /*
+ * If there won't be at least FAKE_NODE_MIN_SIZE of
+ * non-reserved memory in ZONE_DMA32 for the next node,
+ * this one must extend to the boundary.
+ */
+ if (end < dma32_end && dma32_end - end -
+ e820_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
+ end = dma32_end;
+
+ /*
+ * If there won't be enough non-reserved memory for the
+ * next node, this one must extend to the end of the
+ * physical node.
+ */
+ if (physnodes[i].end - end -
+ e820_hole_size(end, physnodes[i].end) < size)
+ end = physnodes[i].end;
+
+ /*
+ * Setup the fake node that will be allocated as bootmem
+ * later. If setup_node_range() returns non-zero, there
+ * is no more memory available on this physical node.
+ */
+ if (setup_node_range(ret++, &physnodes[i].start,
+ end - physnodes[i].start,
+ physnodes[i].end) < 0)
+ node_clear(i, physnode_mask);
+ }
+ }
+ return ret;
+}
+
+/*
* Splits num_nodes nodes up equally starting at node_start. The return value
* is the number of nodes split up and addr is adjusted to be at the end of the
* last node allocated.
@@ -546,14 +642,7 @@ static int __init split_nodes_equally(u64 *addr, u64 max_addr, int node_start,
if (i == num_nodes + node_start - 1)
end = max_addr;
else
- while (end - *addr - e820_hole_size(*addr, end) <
- size) {
- end += FAKE_NODE_MIN_SIZE;
- if (end > max_addr) {
- end = max_addr;
- break;
- }
- }
+ end = find_end_of_node(*addr, max_addr, size);
if (setup_node_range(i, addr, end - *addr, max_addr) < 0)
break;
}
@@ -589,6 +678,18 @@ static int __init numa_emulation(unsigned long start_pfn,
num_phys_nodes = setup_physnodes(addr, max_addr, acpi, k8);
/*
+ * If the numa=fake command-line contains a 'M' or 'G', it represents
+ * the fixed node size.
+ */
+ if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+ size = memparse(cmdline, &cmdline);
+ num_nodes = split_nodes_size_interleave(addr, max_addr, size);
+ if (num_nodes < 0)
+ return num_nodes;
+ goto out;
+ }
+
+ /*
* If the numa=fake command-line is just a single number N, split the
* system RAM into N fake nodes.
*/
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