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.
Note that the existing cpumask_of_cpu() macro is also 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
git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
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 | 39 +++++++++++++++++++++++++++++++++++++++
include/linux/cpumask.h | 12 +++++++++---
3 files changed, 51 insertions(+), 3 deletions(-)
--- linux.trees.git.orig/arch/x86/Kconfig
+++ linux.trees.git/arch/x86/Kconfig
@@ -123,6 +123,9 @@ 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.trees.git.orig/arch/x86/kernel/setup.c
+++ linux.trees.git/arch/x86/kernel/setup.c
@@ -10,6 +10,21 @@
#include <asm/setup.h>
#include <asm/topology.h>
+#ifdef CONFIG_SMP
+/* setup nr_cpu_ids early */
+static void __init setup_nr_cpu_ids(void)
+{
+ int cpu, highest_cpu = 0;
+
+ for_each_possible_cpu(cpu)
+ highest_cpu = cpu;
+
+ nr_cpu_ids = highest_cpu + 1;
+}
+#else
+static inline void setup_nr_cpu_ids(void) { }
+#endif
+
#if defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) && defined(CONFIG_SMP)
/*
* Copy data used in early init routines from the initial arrays to the
@@ -38,6 +53,24 @@ 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
@@ -90,8 +123,14 @@ void __init setup_per_cpu_areas(void)
memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
}
+ /* Setup nr_cpu_ids */
+ setup_nr_cpu_ids();
+
/* Setup percpu data maps */
setup_per_cpu_maps();
+
+ /* Setup cpumask_of_cpu map */
+ setup_cpumask_of_cpu();
}
#endif
--- linux.trees.git.orig/include/linux/cpumask.h
+++ linux.trees.git/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)
--
--
