Messages in this thread Patch in this message | | | Date | Thu, 16 Oct 2008 10:56:46 -0700 | From | Greg KH <> | Subject | [patch 12/14] x86: improve UP kernel when CPU-hotplug and SMP is enabled |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: Thomas Gleixner <tglx@linutronix.de>
commit 649c6653fa94ec8f3ea32b19c97b790ec4e8e4ac upstream
num_possible_cpus() can be > 1 when disabled CPUs have been accounted.
Disabled CPUs are not in the cpu_present_map, so we can use num_present_cpus() as a safe indicator to switch to UP alternatives.
Reported-by: Chuck Ebbert <cebbert@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/kernel/alternative.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -444,7 +444,7 @@ void __init alternative_instructions(voi _text, _etext); /* Only switch to UP mode if we don't immediately boot others */ - if (num_possible_cpus() == 1 || setup_max_cpus <= 1) + if (num_present_cpus() == 1 || setup_max_cpus <= 1) alternatives_smp_switch(0); } #endif --
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