[PATCH] enable X86_PC for HOTPLUG_CPU
CPU_HOTPLUG has race conditions when we use broadcast mode IPI.
- First we introduced no_broadcast option
(see include/asm-i386/mach-default/mach_ipi.h)
- x86_64 solved it by using physical flat mode (same as bigsmp on i386)
since this will not use broadcast shortcuts for IPI.
- We switched to use bigsmp on i386 so that we can have same handling as
x86_64, but apparently this caused an error message, if kernel was
compiled without X86_GENERICARCH, X86_BIGSMP. The message "You have >8
CPUS..." which was bogus and misleading, and only indicated one of the
above ARCH wasnt selected.
So we do not switch to automatic bigsmp for HOTPLUG_CPU support in i386
until the other related config dependencies for SMP_SUSPEND etc can be done
right.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 18ec9fe..366b401 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -756,7 +756,7 @@
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
- depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER && !X86_PC
+ depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
---help---
Say Y here to experiment with turning CPUs off and on. CPUs
can be controlled through /sys/devices/system/cpu.