Commit 9f0e8d04 authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
Browse files

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.

Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarMike Travis <travis@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 321a8e9d

arch/x86/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -117,6 +117,9 @@ 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

arch/x86/kernel/setup.c

+27 −1
Original line number Diff line number Diff line
@@ -54,6 +54,24 @@ static void __init setup_per_cpu_maps(void) 
#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
@@ -70,7 +88,7 @@ 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
@@ -104,10 +122,18 @@ 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

include/linux/cpumask.h

+9 −3
Original line number Diff line number Diff line
@@ -222,8 +222,13 @@ int __next_cpu(int n, const cpumask_t *srcp); 
#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 *srcp); 
		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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