[patch v2] x86: reduce srat verbosity in the kernel log

[David Rientjes]

On Wed, 28 Oct 2009, Andi Kleen wrote:

> For now at least seems reasonable to limit to 128 or so yes (and go
> back to the stack). if we ever have sparse apic ids for nodes 
> then that might change; but in this case could still just do
> a acpidump or teach the printer to be more clever and support
> strides.
> 

It'll support sparse apicids, which was shown in Mike's example, although 
it only becomes a problem when they cannot be represented in a 128 
character buffer.  I doubt there are many machines where that happens 
given the way they are formed.

> It would be just good to have some indication in the output
> if there was a overflow.
> 

Agreed, a trailing "..." would be appropriate.



x86: reduce srat verbosity in the kernel log

It's possible to reduce the number of SRAT messages emitted to the kernel
log by printing each valid pxm once and then creating bitmaps to represent
the apic ids that map to the same node.

This reduces lines such as

	SRAT: PXM 0 -> APIC 0 -> Node 0
	SRAT: PXM 0 -> APIC 1 -> Node 0
	SRAT: PXM 1 -> APIC 2 -> Node 1
	SRAT: PXM 1 -> APIC 3 -> Node 1

to

	SRAT: PXM 0 -> APIC {0-1} -> Node 0
	SRAT: PXM 1 -> APIC {2-3} -> Node 1

The buffer used to store the apic id list is 128 characters in length.
If that is too small to represent all the apic id ranges that are bound
to a single pxm, a trailing "..." is added.  APICID_LIST_LEN should be
manually increased for such configurations.

Acked-by: Mike Travis <travis@xxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
 arch/x86/mm/srat_64.c |   41 +++++++++++++++++++++++++++++++++++++----
 drivers/acpi/numa.c   |    5 +++++
 include/linux/acpi.h  |    3 ++-
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c
--- a/arch/x86/mm/srat_64.c
+++ b/arch/x86/mm/srat_64.c
@@ -36,6 +36,9 @@ static int num_node_memblks __initdata;
 static struct bootnode node_memblk_range[NR_NODE_MEMBLKS] __initdata;
 static int memblk_nodeid[NR_NODE_MEMBLKS] __initdata;
 
+static DECLARE_BITMAP(apicid_map, MAX_LOCAL_APIC) __initdata;
+#define APICID_LIST_LEN	(128)
+
 static __init int setup_node(int pxm)
 {
 	return acpi_map_pxm_to_node(pxm);
@@ -136,8 +139,6 @@ acpi_numa_x2apic_affinity_init(struct acpi_srat_x2apic_cpu_affinity *pa)
 	apicid_to_node[apic_id] = node;
 	node_set(node, cpu_nodes_parsed);
 	acpi_numa = 1;
-	printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
-	       pxm, apic_id, node);
 }
 
 /* Callback for Proximity Domain -> LAPIC mapping */
@@ -170,8 +171,40 @@ acpi_numa_processor_affinity_init(struct acpi_srat_cpu_affinity *pa)
 	apicid_to_node[apic_id] = node;
 	node_set(node, cpu_nodes_parsed);
 	acpi_numa = 1;
-	printk(KERN_INFO "SRAT: PXM %u -> APIC %u -> Node %u\n",
-	       pxm, apic_id, node);
+}
+
+void __init acpi_numa_print_srat_mapping(void)
+{
+	char apicid_list[APICID_LIST_LEN];
+	int i, j;
+
+	for (i = 0; i < MAX_PXM_DOMAINS; i++) {
+		int len;
+		int nid;
+
+		nid = pxm_to_node(i);
+		if (nid == NUMA_NO_NODE)
+			continue;
+
+		bitmap_zero(apicid_map, MAX_LOCAL_APIC);
+		for (j = 0; j < MAX_LOCAL_APIC; j++)
+			if (apicid_to_node[j] == nid)
+				set_bit(j, apicid_map);
+
+		if (bitmap_empty(apicid_map, MAX_LOCAL_APIC))
+			continue;
+
+		/*
+		 * If the bitmap cannot be listed in a buffer of length
+		 * APICID_LIST_LEN, then it is suffixed with "...".
+		 */
+		len = bitmap_scnlistprintf(apicid_list, APICID_LIST_LEN,
+					   apicid_map, MAX_LOCAL_APIC);
+		pr_info("SRAT: PXM %u -> APIC {%s%s} -> Node %u\n",
+			i, apicid_list,
+			(len == APICID_LIST_LEN - 1) ? "..." : "",
+			nid);
+	}
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -281,6 +281,10 @@ acpi_table_parse_srat(enum acpi_srat_type id,
 					    handler, max_entries);
 }
 
+void __init __attribute__((weak)) acpi_numa_print_srat_mapping(void)
+{
+}
+
 int __init acpi_numa_init(void)
 {
 	/* SRAT: Static Resource Affinity Table */
@@ -292,6 +296,7 @@ int __init acpi_numa_init(void)
 		acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
 				      acpi_parse_memory_affinity,
 				      NR_NODE_MEMBLKS);
+		acpi_numa_print_srat_mapping();
 	}
 
 	/* SLIT: System Locality Information Table */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -92,12 +92,13 @@ int acpi_table_parse_madt (enum acpi_madt_type id, acpi_table_entry_handler hand
 int acpi_parse_mcfg (struct acpi_table_header *header);
 void acpi_table_print_madt_entry (struct acpi_subtable_header *madt);
 
-/* the following four functions are architecture-dependent */
+/* the following six functions are architecture-dependent */
 void acpi_numa_slit_init (struct acpi_table_slit *slit);
 void acpi_numa_processor_affinity_init (struct acpi_srat_cpu_affinity *pa);
 void acpi_numa_x2apic_affinity_init(struct acpi_srat_x2apic_cpu_affinity *pa);
 void acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity *ma);
 void acpi_numa_arch_fixup(void);
+void acpi_numa_print_srat_mapping(void);
 
 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 /* Arch dependent functions for cpu hotplug support */
--
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