[Linux-ia64] Re: [PATCH] topology for ia64

Erich Focht
2002-10-22T09:23:37Z

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On Tuesday 22 October 2002 02:07, David Mosberger wrote:
> Why does the cpu_to_node_map[] exist for non-NUMA configurations? It
> seems to me that it would be better to make cpu_to_node_map a macro
> that uses an array-check for NUMA configurations and a simple test
> against phys_cpu_present_map() for non-NUMA.

Attached is a modified patch for implementing the topology stuff on ia64.
It's on top of your 2.5.39 tree including acpi_numa and the acpi_numa fix
which I've sent you separately.

I dropped the cpu_to_node_map array for the non-NUMA case. The macro
__cpu_to_node() returns 0 in this case. In the places where it is used
(e.g. in the NUMA scheduler) we either run on a valid CPU or have
cpu_online() checks before using it, therefore I also removed the
phys_cpu_present_map check when building the cpu to node map.

Hope this can be included now...

Regards,
Erich

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diff -urNp 2.5.39-ia64-acpi-dmf/arch/ia64/kernel/acpi.c 2.5.39-ia64-acpi-dmf-top/arch/ia64/kernel/acpi.c
--- 2.5.39-ia64-acpi-dmf/arch/ia64/kernel/acpi.c Mon Oct 14 15:34:40 2002
+++ 2.5.39-ia64-acpi-dmf-top/arch/ia64/kernel/acpi.c Tue Oct 22 10:44:26 2002
@@ -784,6 +784,9 @@ acpi_boot_init (char *cmdline)
smp_boot_data.cpu_count = total_cpus;

smp_build_cpu_map();
+#ifdef CONFIG_NUMA
+ build_cpu_to_node_map();
+#endif
#endif
/* Make boot-up look pretty */
printk("%d CPUs available, %d CPUs total\n", available_cpus, total_cpus);
diff -urNp 2.5.39-ia64-acpi-dmf/arch/ia64/kernel/smpboot.c 2.5.39-ia64-acpi-dmf-top/arch/ia64/kernel/smpboot.c
--- 2.5.39-ia64-acpi-dmf/arch/ia64/kernel/smpboot.c Fri Sep 27 23:49:16 2002
+++ 2.5.39-ia64-acpi-dmf-top/arch/ia64/kernel/smpboot.c Tue Oct 22 10:57:22 2002
@@ -16,6 +16,7 @@

#include <linux/config.h>

+#include <linux/acpi.h>
#include <linux/bootmem.h>
#include <linux/delay.h>
#include <linux/init.h>
@@ -427,6 +428,32 @@ smp_build_cpu_map (void)
}
}

+#ifdef CONFIG_NUMA
+char cpu_to_node_map[NR_CPUS] __cacheline_aligned;
+/*
+ * Build cpu to node mapping.
+ */
+void __init
+build_cpu_to_node_map(void)
+{
+ int cpu, i;
+
+ for(cpu=0; cpu<NR_CPUS; cpu++) {
+ /*
+ * All Itanium NUMA platforms I know use ACPI, so maybe we
+ * can drop this ifdef completely. [EF]
+ */
+#ifdef CONFIG_ACPI_NUMA
+ for(i=0; i<NR_CPUS; i++)
+ if (cpu_physical_id(cpu) == node_cpuid[i].phys_id) {
+ cpu_to_node_map[cpu]=node_cpuid[i].nid;
+ break;
+ }
+#endif
+ }
+}
+#endif
+
/*
* Cycle through the APs sending Wakeup IPIs to boot each.
*/
diff -urNp 2.5.39-ia64-acpi-dmf/include/asm-ia64/numa.h 2.5.39-ia64-acpi-dmf-top/include/asm-ia64/numa.h
--- 2.5.39-ia64-acpi-dmf/include/asm-ia64/numa.h Mon Oct 14 15:34:14 2002
+++ 2.5.39-ia64-acpi-dmf-top/include/asm-ia64/numa.h Tue Oct 22 11:04:05 2002
@@ -22,6 +22,8 @@
# define NR_MEMBLKS (NR_NODES * 8)
#endif

+extern char cpu_to_node_map[NR_CPUS] __cacheline_aligned;
+
/* Stuff below this line could be architecture independent */

extern int num_memblks; /* total number of memory chunks */
diff -urNp 2.5.39-ia64-acpi-dmf/include/asm-ia64/topology.h 2.5.39-ia64-acpi-dmf-top/include/asm-ia64/topology.h
--- 2.5.39-ia64-acpi-dmf/include/asm-ia64/topology.h Thu Jan 1 01:00:00 1970
+++ 2.5.39-ia64-acpi-dmf-top/include/asm-ia64/topology.h Tue Oct 22 10:43:06 2002
@@ -0,0 +1,79 @@
+/*
+ * linux/include/asm-ia64/topology.h
+ *
+ * Copyright (C) 2002, Erich Focht, NEC
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#ifndef _ASM_IA64_TOPOLOGY_H
+#define _ASM_IA64_TOPOLOGY_H
+
+#include <asm/acpi.h>
+#include <asm/numa.h>
+
+/* Returns the number of the node containing CPU 'cpu' */
+#ifdef CONFIG_NUMA
+#define __cpu_to_node(cpu) cpu_to_node_map[cpu]
+#else
+#define __cpu_to_node(cpu) (0)
+#endif
+
+/*
+ * Returns the number of the node containing MemBlk 'memblk'
+ */
+#ifdef CONFIG_ACPI_NUMA
+#define __memblk_to_node(memblk) (node_memblk[memblk].nid)
+#else
+#define __memblk_to_node(memblk) (memblk)
+#endif
+
+/*
+ * Returns the number of the node containing Node 'nid'.
+ * Not implemented here. Multi-level hierarchies detected with
+ * the help of node_distance().
+ */
+#define __parent_node(nid) (nid)
+
+/*
+ * Returns the number of the first CPU on Node 'node'.
+ * Slow in the current implementation.
+ * Who needs this?
+ */
+/* #define __node_to_first_cpu(node) pool_cpus[pool_ptr[node]] */
+static inline int __node_to_first_cpu(int node)
+{
+ int i, cpu;
+
+ for (i=0; i<NR_CPUS; i++)
+ if (__cpu_to_node(i)==node)
+ return i;
+ BUG(); /* couldn't find a cpu on given node */
+ return -1;
+}
+
+/*
+ * Returns a bitmask of CPUs on Node 'node'.
+ */
+static inline unsigned long __node_to_cpu_mask(int node)
+{
+ int cpu;
+ unsigned long mask = 0UL;
+
+ for(cpu=0; cpu<NR_CPUS; cpu++)
+ if (__cpu_to_node(cpu) == node)
+ mask |= 1UL << cpu;
+ return mask;
+}
+
+/*
+ * Returns the number of the first MemBlk on Node 'node'
+ * Should be fixed when IA64 discontigmem goes in.
+ */
+#define __node_to_memblk(node) (node)
+
+#endif /* _ASM_IA64_TOPOLOGY_H */