[PATCH -v8 00/11] Shutdown from reboot_cpuid without stopping other cpus.

[Ingo Molnar]

* Robin Holt <holt at sgi.com> wrote:

> We recently noticed that reboot of a 1024 cpu machine takes approx 16
> minutes of just stopping the cpus.  The slowdown was tracked to commit
> f96972f.
> 
> The current implementation does all the work of hot removing the cpus
> before halting the system.  We are switching to just migrating to the
> reboot_cpu and then continuing with shutdown/reboot.
> 
> The patch set is broken into eleven parts.  The first two are planned for
> the stable release.  The others move the halt/shutdown/reboot related
> functions to their own kernel/reboot.c file and then move the handling
> of the kernel reboot= kernel parameter to generic kernel code.
> 
> 
> Changes since -v8
>  - Changes reboot_cpu on stack to cpu to fix bug noticed by Russell King.
> 
>  - Switched unicore32 and arm from using REBOOT_WARM/COLD to HARD/SOFT.
> 
>  - Fixed case statement bug.
> 
>  - Went to using simple_strtoul for parsing reboot_cpu=smp###.
> 
>  - Made parsing of reboot= not use any #ifdef'd code.
> 
> Changes since -v7.
>  - Fixed authorship for first patch.
> 
>  - Rebased to Linus' current tree (51a26ae7a).
> 
> Changes since -v6.
>  - Cross compiled all arm architectures (using v3.9 kernel.  Fails with
>    current).
> 
>  - Added a #define for non-hotplug case.
> 
>  - Add #define for PF_THREAD_BOUND as compatibility to make stable easier.
> 
>  - Fixup s/reboot_cpu_id/reboot_cpu/
> 
>  - Add include of linux/uaccess.h to allow building on arm.
> 
>  - Removed last remaining checkpatch.pl line length warning on
>    kernel/reboot.c.
> 
>  - Fixed the duplicate handling or the reboot= kernel parameter.
> 
> Changes since -v5.
>  - Moved the arch/x86 reboot= up to the generic kernel code.
> 
> Changes since -v4.
>  - Integrated Srivatsa S. Bhat creating cpu_hotplug_disable()
>    function
> 
>  - Integrated comments by Srivatsa S. Bhat.
> 
>  - Made one more comment consistent with others in function.
> 
> Changes since -v3.
>  - Added a tested-by for the original reporter.
> 
>  - Fix compile failure found by Joe Perches.
> 
>  - Integrated comments by Joe Perches.
> 
> 
> To: Andrew Morton <akpm at linux-foundation.org>
> Cc: H. Peter Anvin <hpa at zytor.com>
> Cc: Russ Anderson <rja at sgi.com>
> Cc: Robin Holt <holt at sgi.com>
> Cc: Russell King <linux at arm.linux.org.uk>
> Cc: Guan Xuetao <gxt at mprc.pku.edu.cn>
> Cc: Linux Kernel Mailing List <linux-kernel at vger.kernel.org>
> Cc: the arch/x86 maintainers <x86 at kernel.org>
> Cc: Arm Mailing List <linux-arm-kernel at lists.infradead.org>

Looks nice now to me. For the x86 bits:

Acked-by: Ingo Molnar <mingo at kernel.org>

Thanks,

	Ingo