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Subject[PATCH 01/12] x86: Convert cpumask_of_cpu macro to allocated array
  * Here is a simple patch to use an allocated array of cpumasks to
represent cpumask_of_cpu() instead of constructing one on the stack.
It's based on the Kconfig option "HAVE_CPUMASK_OF_CPU_MAP" which is
currently only set for x86_64 SMP. Otherwise the the existing
cpumask_of_cpu() is used but has been changed to produce an lvalue
so a pointer to it can be used.

Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
+ x86/latest .../x86/linux-2.6-x86.git
+ sched-devel/latest .../mingo/linux-2.6-sched-devel.git

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
---
arch/x86/Kconfig | 3 +++
arch/x86/kernel/setup.c | 28 +++++++++++++++++++++++++++-
include/linux/cpumask.h | 12 +++++++++---
3 files changed, 39 insertions(+), 4 deletions(-)

--- linux-2.6.x86.orig/arch/x86/Kconfig
+++ linux-2.6.x86/arch/x86/Kconfig
@@ -124,6 +124,9 @@ config ARCH_HAS_CPU_RELAX
config HAVE_SETUP_PER_CPU_AREA
def_bool X86_64 || (X86_SMP && !X86_VOYAGER)

+config HAVE_CPUMASK_OF_CPU_MAP
+ def_bool X86_64_SMP
+
config ARCH_HIBERNATION_POSSIBLE
def_bool y
depends on !SMP || !X86_VOYAGER
--- linux-2.6.x86.orig/arch/x86/kernel/setup.c
+++ linux-2.6.x86/arch/x86/kernel/setup.c
@@ -38,6 +38,24 @@ static void __init setup_per_cpu_maps(vo
#endif
}

+#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP
+cpumask_t *cpumask_of_cpu_map __read_mostly;
+EXPORT_SYMBOL(cpumask_of_cpu_map);
+
+/* requires nr_cpu_ids to be initialized */
+static void __init setup_cpumask_of_cpu(void)
+{
+ int i;
+
+ /* alloc_bootmem zeroes memory */
+ cpumask_of_cpu_map = alloc_bootmem_low(sizeof(cpumask_t) * nr_cpu_ids);
+ for (i = 0; i < nr_cpu_ids; i++)
+ cpu_set(i, cpumask_of_cpu_map[i]);
+}
+#else
+static inline void setup_cpumask_of_cpu(void) { }
+#endif
+
#ifdef CONFIG_X86_32
/*
* Great future not-so-futuristic plan: make i386 and x86_64 do it
@@ -54,7 +72,7 @@ EXPORT_SYMBOL(__per_cpu_offset);
*/
void __init setup_per_cpu_areas(void)
{
- int i;
+ int i, highest_cpu = 0;
unsigned long size;

#ifdef CONFIG_HOTPLUG_CPU
@@ -88,10 +106,18 @@ void __init setup_per_cpu_areas(void)
__per_cpu_offset[i] = ptr - __per_cpu_start;
#endif
memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
+
+ highest_cpu = i;
}

+ nr_cpu_ids = highest_cpu + 1;
+ printk(KERN_DEBUG "NR_CPUS: %d, nr_cpu_ids: %d\n", NR_CPUS, nr_cpu_ids);
+
/* Setup percpu data maps */
setup_per_cpu_maps();
+
+ /* Setup cpumask_of_cpu map */
+ setup_cpumask_of_cpu();
}

#endif
--- linux-2.6.x86.orig/include/linux/cpumask.h
+++ linux-2.6.x86/include/linux/cpumask.h
@@ -222,8 +222,13 @@ int __next_cpu(int n, const cpumask_t *s
#define next_cpu(n, src) ({ (void)(src); 1; })
#endif

+#ifdef CONFIG_HAVE_CPUMASK_OF_CPU_MAP
+extern cpumask_t *cpumask_of_cpu_map;
+#define cpumask_of_cpu(cpu) (cpumask_of_cpu_map[cpu])
+
+#else
#define cpumask_of_cpu(cpu) \
-({ \
+(*({ \
typeof(_unused_cpumask_arg_) m; \
if (sizeof(m) == sizeof(unsigned long)) { \
m.bits[0] = 1UL<<(cpu); \
@@ -231,8 +236,9 @@ int __next_cpu(int n, const cpumask_t *s
cpus_clear(m); \
cpu_set((cpu), m); \
} \
- m; \
-})
+ &m; \
+}))
+#endif

#define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS)

--


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