[PATCH v2] powerpc: enforce sane MAX_ORDER
powerpc uses CONFIG_FORCE_MAX_ZONEORDER, and some things depend on it being at least 10 when 64k pages are not configured (notably the dart iommu code with CONFIG_PM). The defaults are fine, but when going from a 64K pages config to one without 64K pages, MAX_ORDER stays at 9 which is too low for 4K pages. This patch makes the Kconfig enforce at least the defaults. Signed-off-by: Johannes Berg [EMAIL PROTECTED] --- We'll I'm ok with that, but I dont think we should be values that make no sense. 64 would seem the max even in a 64-bit system. Indeed, it makes little sense to allow you to set more than the address space, so here's a version with max 64. --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -415,8 +415,11 @@ config PPC_64K_PAGES config FORCE_MAX_ZONEORDER int Maximum zone order + range 9 64 if PPC_64K_PAGES default 9 if PPC_64K_PAGES + range 13 64 if PPC64 !PPC_64K_PAGES default 13 if PPC64 !PPC_64K_PAGES + range 11 64 default 11 help The kernel memory allocator divides physically contiguous memory ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [PATCH v2] powerpc: enforce sane MAX_ORDER
On Wed, Sep 24, 2008 at 9:29 AM, Johannes Berg [EMAIL PROTECTED] wrote: Indeed, it makes little sense to allow you to set more than the address space, so here's a version with max 64. Acked-by: Timur Tabi [EMAIL PROTECTED] However, the max is actually less than 64. Assuming a 64-bit address space, the maximum number of pages in one allocation can be 2^(64-PAGE_SHIFT). For 4KB pages, the max value for FORCE_MAX_ZONEORDER is 53. For 64KB pages, the max is 49. -- Timur Tabi Linux kernel developer at Freescale ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
