[PATCH] in-kernel topology API

From Matthew Dobson <colpatch@us.ibm.com>

"This patch adds a 'simple' in-kernel topology API.  This API allows
 for three primary topology elements: CPUs, memory blocks, and nodes.
 The API allows for the discovery of which CPUs/Memory Blocks reside on
 which nodes, and vice versa.  Also implemented is a macro to get a
 bitmask of CPUs on a particular node.  This API is platform neutral."

We need this API for per-node-kswapd - without it there is no means by
which each kswapd can be bound to its node's CPUs.  And we rather need
per-node-kswapd...

The patch also uses the new API to bind each kswapd instance to its
node's CPUs

include/asm-alpha/mmzone.h

@@ -107,15 +107,6 @@ PLAT_NODE_DATA_LOCALNR(unsigned long p, int n)
 #ifdef CONFIG_NUMA_SCHED
 #define NODE_SCHEDULE_DATA(nid)	(&((PLAT_NODE_DATA(nid))->schedule_data))
 #endif
-
-#ifdef CONFIG_ALPHA_WILDFIRE
-/* With wildfire assume 4 CPUs per node */
-#define cputonode(cpu)	((cpu) >> 2)
-#else
-#define cputonode(cpu)	0
-#endif /* CONFIG_ALPHA_WILDFIRE */
-
-#define numa_node_id()	cputonode(smp_processor_id())
 #endif /* CONFIG_NUMA */
 
 #endif /* CONFIG_DISCONTIGMEM */

include/asm-alpha/topology.h

+#ifndef _ASM_ALPHA_TOPOLOGY_H
+#define _ASM_ALPHA_TOPOLOGY_H
+
+#ifdef CONFIG_NUMA
+#ifdef CONFIG_ALPHA_WILDFIRE
+/* With wildfire assume 4 CPUs per node */
+#define __cpu_to_node(cpu)	((cpu) >> 2)
+#endif /* CONFIG_ALPHA_WILDFIRE */
+#endif /* CONFIG_NUMA */
+
+/* Get the rest of the topology definitions */
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_ALPHA_TOPOLOGY_H */

include/asm-arm/topology.h

+#ifndef _ASM_ARM_TOPOLOGY_H
+#define _ASM_ARM_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_ARM_TOPOLOGY_H */

include/asm-cris/topology.h

+#ifndef _ASM_CRIS_TOPOLOGY_H
+#define _ASM_CRIS_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_CRIS_TOPOLOGY_H */

include/asm-generic/topology.h

+/*
+ * linux/include/asm-generic/topology.h
+ *
+ * Written by: Matthew Dobson, IBM Corporation
+ *
+ * Copyright (C) 2002, IBM Corp.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to <colpatch@us.ibm.com>
+ */
+#ifndef _ASM_GENERIC_TOPOLOGY_H
+#define _ASM_GENERIC_TOPOLOGY_H
+
+/* Other architectures wishing to use this simple topology API should fill
+   in the below functions as appropriate in their own <asm/topology.h> file. */
+#ifndef __cpu_to_node
+#define __cpu_to_node(cpu)		(0)
+#endif
+#ifndef __memblk_to_node
+#define __memblk_to_node(memblk)		(0)
+#endif
+#ifndef __parent_node
+#define __parent_node(nid)		(0)
+#endif
+#ifndef __node_to_first_cpu
+#define __node_to_first_cpu(node)	(0)
+#endif
+#ifndef __node_to_cpu_mask
+#define __node_to_cpu_mask(node)		(cpu_online_map)
+#endif
+#ifndef __node_to_memblk
+#define __node_to_memblk(node)		(0)
+#endif
+
+#endif /* _ASM_GENERIC_TOPOLOGY_H */

include/asm-i386/mmzone.h

@@ -19,10 +19,6 @@
 #endif /* CONFIG_NUMA */
 #endif /* CONFIG_X86_NUMAQ */
 
-#ifdef CONFIG_NUMA
-#define numa_node_id() _cpu_to_node(smp_processor_id())
-#endif /* CONFIG_NUMA */
-
 extern struct pglist_data *node_data[];
 
 /*

include/asm-i386/topology.h

+/*
+ * linux/include/asm-i386/topology.h
+ *
+ * Written by: Matthew Dobson, IBM Corporation
+ *
+ * Copyright (C) 2002, IBM Corp.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to <colpatch@us.ibm.com>
+ */
+#ifndef _ASM_I386_TOPOLOGY_H
+#define _ASM_I386_TOPOLOGY_H
+
+#ifdef CONFIG_X86_NUMAQ
+
+#include <asm/smpboot.h>
+
+/* Returns the number of the node containing CPU 'cpu' */
+#define __cpu_to_node(cpu) (cpu_to_logical_apicid(cpu) >> 4)
+
+/* Returns the number of the node containing MemBlk 'memblk' */
+#define __memblk_to_node(memblk) (memblk)
+
+/* Returns the number of the node containing Node 'nid'.  This architecture is flat, 
+   so it is a pretty simple function! */
+#define __parent_node(nid) (nid)
+
+/* Returns the number of the first CPU on Node 'node'.
+ * This should be changed to a set of cached values
+ * but this will do for now.
+ */
+static inline int __node_to_first_cpu(int node)
+{
+	int i, cpu, logical_apicid = node << 4;
+
+	for(i = 1; i < 16; i <<= 1)
+		/* check to see if the cpu is in the system */
+		if ((cpu = logical_apicid_to_cpu(logical_apicid | i)) >= 0)
+			/* if yes, return it to caller */
+			return cpu;
+
+	return 0;
+}
+
+/* Returns a bitmask of CPUs on Node 'node'.
+ * This should be changed to a set of cached bitmasks
+ * but this will do for now.
+ */
+static inline unsigned long __node_to_cpu_mask(int node)
+{
+	int i, cpu, logical_apicid = node << 4;
+	unsigned long mask = 0UL;
+
+	for(i = 1; i < 16; i <<= 1)
+		/* check to see if the cpu is in the system */
+		if ((cpu = logical_apicid_to_cpu(logical_apicid | i)) >= 0)
+			/* if yes, add to bitmask */
+			mask |= 1 << cpu;
+
+	return mask;
+}
+
+/* Returns the number of the first MemBlk on Node 'node' */
+#define __node_to_memblk(node) (node)
+
+#else /* !CONFIG_X86_NUMAQ */
+/*
+ * Other i386 platforms should define their own version of the 
+ * above macros here.
+ */
+
+#include <asm-generic/topology.h>
+
+#endif /* CONFIG_X86_NUMAQ */
+
+#endif /* _ASM_I386_TOPOLOGY_H */

include/asm-ia64/topology.h

+#ifndef _ASM_IA64_TOPOLOGY_H
+#define _ASM_IA64_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_IA64_TOPOLOGY_H */

include/asm-m68k/topology.h

+#ifndef _ASM_M68K_TOPOLOGY_H
+#define _ASM_M68K_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_M68K_TOPOLOGY_H */

include/asm-mips/topology.h

+#ifndef _ASM_MIPS_TOPOLOGY_H
+#define _ASM_MIPS_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_MIPS_TOPOLOGY_H */

include/asm-mips64/mmzone.h

@@ -28,8 +28,6 @@ extern plat_pg_data_t *plat_node_data[];
 #define PLAT_NODE_DATA_LOCALNR(p, n) \
 		(((p) >> PAGE_SHIFT) - PLAT_NODE_DATA(n)->gendata.node_start_pfn)
 
-#define numa_node_id()	cputocnode(current->processor)
-
 #ifdef CONFIG_DISCONTIGMEM
 
 /*

include/asm-mips64/topology.h

+#ifndef _ASM_MIPS64_TOPOLOGY_H
+#define _ASM_MIPS64_TOPOLOGY_H
+
+#include <asm/mmzone.h>
+
+#define __cpu_to_node(cpu)		(cputocnode(cpu))
+
+/* Get the rest of the topology definitions */
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_MIPS64_TOPOLOGY_H */

include/asm-parisc/topology.h

+#ifndef _ASM_PARISC_TOPOLOGY_H
+#define _ASM_PARISC_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_PARISC_TOPOLOGY_H */

include/asm-ppc/topology.h

+#ifndef _ASM_PPC_TOPOLOGY_H
+#define _ASM_PPC_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_PPC_TOPOLOGY_H */

include/asm-ppc64/mmzone.h

@@ -72,7 +72,6 @@ static inline int __cpu_to_node(int cpu)
 	return node;
 }
 
-#define numa_node_id()	__cpu_to_node(smp_processor_id())
 #endif /* CONFIG_NUMA */
 
 /*

include/asm-ppc64/topology.h

+#ifndef _ASM_PPC64_TOPOLOGY_H
+#define _ASM_PPC64_TOPOLOGY_H
+
+#include <asm/mmzone.h>
+
+#ifdef CONFIG_NUMA
+/* XXX grab this from the device tree - Anton */
+#define __cpu_to_node(cpu)	((cpu) >> CPU_SHIFT_BITS)
+#endif /* CONFIG_NUMA */
+
+/* Get the rest of the topology definitions */
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_PPC64_TOPOLOGY_H */

include/asm-s390/topology.h

+#ifndef _ASM_S390_TOPOLOGY_H
+#define _ASM_S390_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_S390_TOPOLOGY_H */

include/asm-s390x/topology.h

+#ifndef _ASM_S390X_TOPOLOGY_H
+#define _ASM_S390X_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_S390X_TOPOLOGY_H */

include/asm-sh/topology.h

+#ifndef _ASM_SH_TOPOLOGY_H
+#define _ASM_SH_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_SH_TOPOLOGY_H */

include/asm-sparc/topology.h

+#ifndef _ASM_SPARC_TOPOLOGY_H
+#define _ASM_SPARC_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_SPARC_TOPOLOGY_H */

include/asm-sparc64/topology.h

+#ifndef _ASM_SPARC64_TOPOLOGY_H
+#define _ASM_SPARC64_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_SPARC64_TOPOLOGY_H */

include/asm-x86_64/topology.h

+#ifndef _ASM_X86_64_TOPOLOGY_H
+#define _ASM_X86_64_TOPOLOGY_H
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_X86_64_TOPOLOGY_H */

include/linux/mmzone.h

@@ -249,13 +249,23 @@ static inline struct zone *next_zone(struct zone *zone)
 #define for_each_zone(zone) \
 	for (zone = pgdat_list->node_zones; zone; zone = next_zone(zone))
 
+#ifdef CONFIG_NUMA
+#define MAX_NR_MEMBLKS	BITS_PER_LONG /* Max number of Memory Blocks */
+#else /* !CONFIG_NUMA */
+#define MAX_NR_MEMBLKS	1
+#endif /* CONFIG_NUMA */
+
+#include <asm/topology.h>
+/* Returns the number of the current Node. */
+#define numa_node_id()		(__cpu_to_node(smp_processor_id()))
+
 #ifndef CONFIG_DISCONTIGMEM
 
 #define NODE_DATA(nid)		(&contig_page_data)
 #define NODE_MEM_MAP(nid)	mem_map
 #define MAX_NR_NODES		1
 
-#else /* !CONFIG_DISCONTIGMEM */
+#else /* CONFIG_DISCONTIGMEM */
 
 #include <asm/mmzone.h>
 

mm/vmscan.c

@@ -30,6 +30,8 @@
 
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
+#include <asm/topology.h>
+
 #include <linux/swapops.h>
 
 /*
@@ -739,6 +741,7 @@ int kswapd(void *p)
 	DECLARE_WAITQUEUE(wait, tsk);
 
 	daemonize();
+	set_cpus_allowed(tsk, __node_to_cpu_mask(pgdat->node_id));
 	sprintf(tsk->comm, "kswapd%d", pgdat->node_id);
 	sigfillset(&tsk->blocked);