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authorRusty Russell <rusty@rustcorp.com.au>2008-12-30 09:05:14 +1030
committerRusty Russell <rusty@rustcorp.com.au>2008-12-30 09:05:14 +1030
commitb3199c025d1646e25e7d1d640dd605db251dccf8 (patch)
tree752bd257f2db6b4d39bf9cdce18ca25ade5e63a9 /include
parentcb78a0ce69fad2026825f957e24e2d9cda1ec9f1 (diff)
downloadop-kernel-dev-b3199c025d1646e25e7d1d640dd605db251dccf8.zip
op-kernel-dev-b3199c025d1646e25e7d1d640dd605db251dccf8.tar.gz
cpumask: switch over to cpu_online/possible/active/present_mask: core
Impact: cleanup This implements the obsolescent cpu_online_map in terms of cpu_online_mask, rather than the other way around. Same for the other maps. The documentation comments are also updated to refer to _mask rather than _map. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cpumask.h75
1 files changed, 29 insertions, 46 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index b5ad19a..db2341b 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -416,65 +416,54 @@ int __next_cpu_nr(int n, const cpumask_t *srcp);
/*
* The following particular system cpumasks and operations manage
- * possible, present, active and online cpus. Each of them is a fixed size
- * bitmap of size NR_CPUS.
+ * possible, present, active and online cpus.
*
- * #ifdef CONFIG_HOTPLUG_CPU
- * cpu_possible_map - has bit 'cpu' set iff cpu is populatable
- * cpu_present_map - has bit 'cpu' set iff cpu is populated
- * cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
- * cpu_active_map - has bit 'cpu' set iff cpu available to migration
- * #else
- * cpu_possible_map - has bit 'cpu' set iff cpu is populated
- * cpu_present_map - copy of cpu_possible_map
- * cpu_online_map - has bit 'cpu' set iff cpu available to scheduler
- * #endif
+ * cpu_possible_mask- has bit 'cpu' set iff cpu is populatable
+ * cpu_present_mask - has bit 'cpu' set iff cpu is populated
+ * cpu_online_mask - has bit 'cpu' set iff cpu available to scheduler
+ * cpu_active_mask - has bit 'cpu' set iff cpu available to migration
*
- * In either case, NR_CPUS is fixed at compile time, as the static
- * size of these bitmaps. The cpu_possible_map is fixed at boot
- * time, as the set of CPU id's that it is possible might ever
- * be plugged in at anytime during the life of that system boot.
- * The cpu_present_map is dynamic(*), representing which CPUs
- * are currently plugged in. And cpu_online_map is the dynamic
- * subset of cpu_present_map, indicating those CPUs available
- * for scheduling.
+ * If !CONFIG_HOTPLUG_CPU, present == possible, and active == online.
*
- * If HOTPLUG is enabled, then cpu_possible_map is forced to have
+ * The cpu_possible_mask is fixed at boot time, as the set of CPU id's
+ * that it is possible might ever be plugged in at anytime during the
+ * life of that system boot. The cpu_present_mask is dynamic(*),
+ * representing which CPUs are currently plugged in. And
+ * cpu_online_mask is the dynamic subset of cpu_present_mask,
+ * indicating those CPUs available for scheduling.
+ *
+ * If HOTPLUG is enabled, then cpu_possible_mask is forced to have
* all NR_CPUS bits set, otherwise it is just the set of CPUs that
* ACPI reports present at boot.
*
- * If HOTPLUG is enabled, then cpu_present_map varies dynamically,
+ * If HOTPLUG is enabled, then cpu_present_mask varies dynamically,
* depending on what ACPI reports as currently plugged in, otherwise
- * cpu_present_map is just a copy of cpu_possible_map.
+ * cpu_present_mask is just a copy of cpu_possible_mask.
*
- * (*) Well, cpu_present_map is dynamic in the hotplug case. If not
- * hotplug, it's a copy of cpu_possible_map, hence fixed at boot.
+ * (*) Well, cpu_present_mask is dynamic in the hotplug case. If not
+ * hotplug, it's a copy of cpu_possible_mask, hence fixed at boot.
*
* Subtleties:
* 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
* assumption that their single CPU is online. The UP
- * cpu_{online,possible,present}_maps are placebos. Changing them
+ * cpu_{online,possible,present}_masks are placebos. Changing them
* will have no useful affect on the following num_*_cpus()
* and cpu_*() macros in the UP case. This ugliness is a UP
* optimization - don't waste any instructions or memory references
* asking if you're online or how many CPUs there are if there is
* only one CPU.
- * 2) Most SMP arch's #define some of these maps to be some
- * other map specific to that arch. Therefore, the following
- * must be #define macros, not inlines. To see why, examine
- * the assembly code produced by the following. Note that
- * set1() writes phys_x_map, but set2() writes x_map:
- * int x_map, phys_x_map;
- * #define set1(a) x_map = a
- * inline void set2(int a) { x_map = a; }
- * #define x_map phys_x_map
- * main(){ set1(3); set2(5); }
*/
-extern cpumask_t cpu_possible_map;
-extern cpumask_t cpu_online_map;
-extern cpumask_t cpu_present_map;
-extern cpumask_t cpu_active_map;
+extern const struct cpumask *const cpu_possible_mask;
+extern const struct cpumask *const cpu_online_mask;
+extern const struct cpumask *const cpu_present_mask;
+extern const struct cpumask *const cpu_active_mask;
+
+/* These strip const, as traditionally they weren't const. */
+#define cpu_possible_map (*(cpumask_t *)cpu_possible_mask)
+#define cpu_online_map (*(cpumask_t *)cpu_online_mask)
+#define cpu_present_map (*(cpumask_t *)cpu_present_mask)
+#define cpu_active_map (*(cpumask_t *)cpu_active_mask)
#if NR_CPUS > 1
#define num_online_cpus() cpus_weight_nr(cpu_online_map)
@@ -1058,12 +1047,6 @@ static inline void free_bootmem_cpumask_var(cpumask_var_t mask)
}
#endif /* CONFIG_CPUMASK_OFFSTACK */
-/* The pointer versions of the maps, these will become the primary versions. */
-#define cpu_possible_mask ((const struct cpumask *)&cpu_possible_map)
-#define cpu_online_mask ((const struct cpumask *)&cpu_online_map)
-#define cpu_present_mask ((const struct cpumask *)&cpu_present_map)
-#define cpu_active_mask ((const struct cpumask *)&cpu_active_map)
-
/* It's common to want to use cpu_all_mask in struct member initializers,
* so it has to refer to an address rather than a pointer. */
extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS);
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