[PATCH V3 0/2] pseries/nodes: Fix issues with memoryless nodes

[PATCH V3 0/2] pseries/nodes: Fix issues with memoryless nodes

[Michael Bringmann]

pseries/nodes: Ensure enough nodes avail for operations

pseries/initnodes: Ensure nodes initialized for hotplug

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>

Michael Bringmann (2):
  pseries/nodes: Ensure enough nodes avail for operations
  pseries/initnodes: Ensure nodes initialized for hotplug

[PATCH V3 1/2] pseries/nodes: Ensure enough nodes avail for operations

[Michael Bringmann]

pseries/nodes: On pseries systems which allow 'hot-add' of CPU or
memory resources, it may occur that the new resources are to be
inserted into nodes that were not used for these resources at bootup.
In the kernel, any node that is used must be defined and initialized.
This patch ensures that sufficient nodes are defined to support
configuration requirements after boot, as well as at boot.

This patch extracts the value of the lowest domain level (number
of allocable resources) from the device tree property
"ibm,max-associativity-domains" to use as the maximum number of nodes
to setup as possibly available in the system.  This new setting will
override the instruction,

    nodes_and(node_possible_map, node_possible_map, node_online_map);

presently seen in the function arch/powerpc/mm/numa.c:initmem_init().

If the property is not present at boot, no operation will be performed
to define or enable additional nodes.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
---
 arch/powerpc/mm/numa.c |   39 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index ec098b3..f885ab7 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -892,6 +892,36 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
 	NODE_DATA(nid)->node_spanned_pages = spanned_pages;
 }
 
+static void __init find_possible_nodes(void)
+{
+	struct device_node *rtas;
+	u32 numnodes, i;
+
+	if (min_common_depth <= 0)
+		return;
+
+	rtas = of_find_node_by_path("/rtas");
+	if (!rtas)
+		return;
+
+	if (of_property_read_u32_index(rtas,
+				"ibm,max-associativity-domains",
+				min_common_depth, &numnodes))
+		goto out;
+
+	pr_info("numa: Nodes = %d (mcd = %d)\n", numnodes,
+		min_common_depth);
+
+	for (i = 0; i < numnodes; i++) {
+		if (!node_possible(i))
+			node_set(i, node_possible_map);
+	}
+
+out:
+	if (rtas)
+		of_node_put(rtas);
+}
+
 void __init initmem_init(void)
 {
 	int nid, cpu;
@@ -905,12 +935,15 @@ void __init initmem_init(void)
 	memblock_dump_all();
 
 	/*
-	 * Reduce the possible NUMA nodes to the online NUMA nodes,
-	 * since we do not support node hotplug. This ensures that  we
-	 * lower the maximum NUMA node ID to what is actually present.
+	 * Modify the set of possible NUMA nodes to reflect information
+	 * available about the set of online nodes, and the set of nodes
+	 * that we expect to make use of for this platform's affinity
+	 * calculations.
 	 */
 	nodes_and(node_possible_map, node_possible_map, node_online_map);
 
+	find_possible_nodes();
+
 	for_each_online_node(nid) {
 		unsigned long start_pfn, end_pfn;
 

[PATCH V3 2/2] pseries/initnodes: Ensure nodes initialized for hotplug

[Michael Bringmann]

To: linuxppc-dev@lists.ozlabs.org
To: linux-kernel@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Subject: [PATCH V3 2/2] pseries/initnodes: Ensure nodes initialized for hotplug

pseries/nodes: On pseries systems which allow 'hot-add' of CPU,
it may occur that the new resources are to be inserted into nodes
that were not used for memory resources at bootup.  Many different
configurations of PowerPC resources may need to be supported depending
upon the environment.  This patch fixes some problems encountered at
runtime with configurations that support memory-less nodes, or that
hot-add resources during system execution after boot.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
---
 arch/powerpc/mm/numa.c |   35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index f885ab7..37f697dc1 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -551,7 +551,7 @@ static int numa_setup_cpu(unsigned long lcpu)
 	nid = of_node_to_nid_single(cpu);
 
 out_present:
-	if (nid < 0 || !node_online(nid))
+	if (nid < 0 || !node_possible(nid))
 		nid = first_online_node;
 
 	map_cpu_to_node(lcpu, nid);
@@ -1311,6 +1311,35 @@ static long vphn_get_associativity(unsigned long cpu,
 	return rc;
 }
 
+static int verify_node_preparation(int nid)
+{
+	/*
+	 * Need to allocate/initialize NODE_DATA from a node with
+	 * memory (see memblock_alloc_try_nid).  Code executed after
+	 * boot (like local_memory_node) often does not know enough
+	 * to recover fully for memoryless nodes. 
+	 */
+	if (NODE_DATA(nid) == NULL) {
+		int ret;
+		printk(KERN_INFO "%s:%d node %d (%d)\n", __FUNCTION__, __LINE__, nid, first_online_node);
+		setup_node_data(nid, 0, 0);
+		printk(KERN_INFO "%s:%d node %d (%d)\n", __FUNCTION__, __LINE__, nid, first_online_node);
+		ret = try_online_node(nid);
+		printk(KERN_INFO "%s:%d node %d (%d) %d %p\n", __FUNCTION__, __LINE__, nid, first_online_node, ret, NODE_DATA(nid));
+
+		/*
+		 * Node structures successfully initialized, but
+		 * we still need the node to be offline.
+		 */
+		node_set_offline(nid);
+	}
+
+	if (NODE_DATA(nid)->node_spanned_pages == 0)
+		return first_online_node;
+
+	return nid;
+}
+
 /*
  * Update the CPU maps and sysfs entries for a single CPU when its NUMA
  * characteristics change. This function doesn't perform any locking and is
@@ -1419,9 +1448,11 @@ int numa_update_cpu_topology(bool cpus_locked)
 		/* Use associativity from first thread for all siblings */
 		vphn_get_associativity(cpu, associativity);
 		new_nid = associativity_to_nid(associativity);
-		if (new_nid < 0 || !node_online(new_nid))
+		if (new_nid < 0 || !node_possible(new_nid))
 			new_nid = first_online_node;
 
+		new_nid = verify_node_preparation(new_nid);
+
 		if (new_nid == numa_cpu_lookup_table[cpu]) {
 			cpumask_andnot(&cpu_associativity_changes_mask,
 					&cpu_associativity_changes_mask,

Re: [PATCH V3 2/2] pseries/initnodes: Ensure nodes initialized for hotplug

[kbuild test robot]

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Hi Michael,

[auto build test WARNING on powerpc/next]
[also build test WARNING on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Michael-Bringmann/pseries-nodes-Ensure-enough-nodes-avail-for-operations/20171024-021023
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc 

All warnings (new ones prefixed by >>):

>> WARNING: vmlinux.o(.text+0x820e0): Section mismatch in reference from the function .numa_update_cpu_topology() to the function .init.text:.setup_node_data()
   The function .numa_update_cpu_topology() references
   the function __init .setup_node_data().
   This is often because .numa_update_cpu_topology lacks a __init
   annotation or the annotation of .setup_node_data is wrong.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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