On Fri, 2014-04-04 at 09:18 -0700, Dave Hansen wrote:

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,
you only put it in one place, and folks only have to care if they want
to change the default to be something other than 4.

Also does it have to be a constant ? Maddy here tested on our POWER
servers. The "Sweet spot" value might be VERY different on an embedded
chip or even on a future generation of server chip.

Cheers,
Ben.