On Wed, Apr 09, 2014 at 07:02:02AM +0530, Madhavan Srinivasan wrote:

On Friday 04 April 2014 09:48 PM, Dave Hansen wrote:

quoted

On 04/03/2014 11:27 PM, Madhavan Srinivasan wrote:

quoted

This patch creates infrastructure to move the FAULT_AROUND_ORDER
to arch/ using Kconfig. This will enable architecture maintainers
to decide on suitable FAULT_AROUND_ORDER value based on
performance data for that architecture. Patch also adds
FAULT_AROUND_ORDER Kconfig element in arch/X86.

Please don't do it this way.

In mm/Kconfig, put

	config FAULT_AROUND_ORDER
		int
		default 1234 if POWERPC
		default 4

The way you have it now, every single architecture that needs to enable
this has to go put that in their Kconfig.  That's madness.  This way,

I though about it and decided not to do this way because, in future,
sub platforms of the architecture may decide to change the values. Also,
adding an if line for each architecture with different sub platforms
oring to it will look messy.

This still misses out on Ben's objection that its impossible to get this
right at compile time for many kernels, since they can boot and run on
many different subarchs.