![Borislav Petkov](/assets/img/avatar_default.png)
ea53069231
made a CPU use monitor/mwait
when offline. This is not the optimal choice for AMD wrt to powersavings
and we'd prefer our cores to halt (i.e. enter C1) instead. For this, the
same selection whether to use monitor/mwait has to be used as when we
select the idle routine for the machine.
With this patch, offlining cores 1-5 on a X6 machine allows core0 to
boost again.
[ hpa: putting this in urgent since it is a (power) regression fix ]
Reported-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: stable@kernel.org # 37.x
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.hl>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1295534572-10730-1-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
38 lines
735 B
C
38 lines
735 B
C
#ifndef _ASM_X86_CPU_H
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#define _ASM_X86_CPU_H
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#include <linux/device.h>
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#include <linux/cpu.h>
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#include <linux/topology.h>
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#include <linux/nodemask.h>
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#include <linux/percpu.h>
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#ifdef CONFIG_SMP
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extern void prefill_possible_map(void);
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#else /* CONFIG_SMP */
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static inline void prefill_possible_map(void) {}
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#define cpu_physical_id(cpu) boot_cpu_physical_apicid
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#define safe_smp_processor_id() 0
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#define stack_smp_processor_id() 0
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#endif /* CONFIG_SMP */
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struct x86_cpu {
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struct cpu cpu;
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};
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#ifdef CONFIG_HOTPLUG_CPU
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extern int arch_register_cpu(int num);
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extern void arch_unregister_cpu(int);
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#endif
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DECLARE_PER_CPU(int, cpu_state);
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int __cpuinit mwait_usable(const struct cpuinfo_x86 *);
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#endif /* _ASM_X86_CPU_H */
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