x86: "nosmp" command line option should force the system into UP mode

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Bits set in cpu_possible_mask prior to the execution of
prefill_possible_map() (i.e.  when parsing ACPI or MPS tables) would
prevent the SMP alternatives logic from switching to UP mode, plus
unnecessary setup of per-CPU data for CPUs that can never come online.

Additionally, without CONFIG_HOTPLUG_CPU disabled CPUs can never come
online, and hence setting cpu_possible_mask bits for them is again a
simple waste of resources.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <201005241913.o4OJDH3Z010874@imap1.linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

...

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Jan Beulich 2010-05-24 12:13:17 -07:00 • committed by H. Peter Anvin

parent b46fc5f235

commit 5f2eb55026

1 changed files with 23 additions and 3 deletions

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arch/x86/kernel/smpboot.c

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