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Commit 4bb5e07b authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

[S390] Limit cpu detection to 256 physical cpus. 



Saves us more than 65k pointless IPIs.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 53f8c573

arch/s390/include/asm/cpu.h

0 → 100644
+6 −0
Original line number Diff line number Diff line 
#ifndef _ASM_S390_CPU_H

#define _ASM_S390_CPU_H



#define MAX_CPU_ADDRESS 255



#endif /* _ASM_S390_CPU_H */

arch/s390/kernel/head.S

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <asm/asm-offsets.h>

#include <asm/thread_info.h>

#include <asm/page.h>

#include <asm/cpu.h>



#ifdef CONFIG_64BIT

#define ARCH_OFFSET	4

arch/s390/kernel/head64.S

+3 −5
Original line number Diff line number Diff line
@@ -63,8 +63,8 @@ startup_continue: 
	je	5f			# no more space in prefix array

4:

	ahi	%r8,1			# next cpu (r8 += 1)

	cl	%r8,.Llast_cpu-.LPG1(%r13)	# is last possible cpu ?

	jl	1b				# jump if not last cpu

	chi	%r8,MAX_CPU_ADDRESS	# is last possible cpu ?

	jle	1b			# jump if not last cpu

5:

	lhi	%r1,2			# mode 2 = esame (dump)

	j	6f
@@ -130,8 +130,6 @@ startup_continue: 
#ifdef CONFIG_ZFCPDUMP

.Lcurrent_cpu:

	.long 0x0

.Llast_cpu:

	.long 0x0000ffff

.Lpref_arr_ptr:

	.long zfcpdump_prefix_array

#endif /* CONFIG_ZFCPDUMP */

arch/s390/kernel/smp.c

+3 −2
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 
#include <asm/sclp.h>

#include <asm/cputime.h>

#include <asm/vdso.h>

#include <asm/cpu.h>

#include "entry.h"



static struct task_struct *current_set[NR_CPUS];
@@ -300,7 +301,7 @@ static int smp_rescan_cpus_sigp(cpumask_t avail) 
	logical_cpu = cpumask_first(&avail);

	if (logical_cpu >= nr_cpu_ids)

		return 0;

	for (cpu_id = 0; cpu_id <= 65535; cpu_id++) {

	for (cpu_id = 0; cpu_id <= MAX_CPU_ADDRESS; cpu_id++) {

		if (cpu_known(cpu_id))

			continue;

		__cpu_logical_map[logical_cpu] = cpu_id;
@@ -379,7 +380,7 @@ static void __init smp_detect_cpus(void) 
	/* Use sigp detection algorithm if sclp doesn't work. */

	if (sclp_get_cpu_info(info)) {

		smp_use_sigp_detection = 1;

		for (cpu = 0; cpu <= 65535; cpu++) {

		for (cpu = 0; cpu <= MAX_CPU_ADDRESS; cpu++) {

			if (cpu == boot_cpu_addr)

				continue;

			__cpu_logical_map[CPU_INIT_NO] = cpu;