On Tue, Apr 30, 2013 at 05:30:47PM +0100, Steve Capper wrote: > The buddy allocator has a default order of 11, which is too low to > allocate enough memory for 512MB Transparent HugePages if our base > page size is 64K. For any order less than 13, the combination of > THP with 64K pages will cause a compile error. > > This patch introduces the MAX_ZONE_ORDER config option that allows > one to explicitly override the order of the buddy allocator. If > 64K pages and THP are enabled the minimum value is set to 13. > > Signed-off-by: Steve Capper <steve.capper@xxxxxxxxxx> > --- > arch/arm64/Kconfig | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 16aa780..908fd95 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -196,6 +196,23 @@ config ARCH_WANT_HUGE_PMD_SHARE > > source "mm/Kconfig" > > +config FORCE_MAX_ZONEORDER > + int "Maximum zone order" > + range 11 64 if !(ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) > + range 13 64 if ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE > + default "11" if !(ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) > + default "13" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) Can we just keep some sane defaults here without giving too much choice to the user? Something like: config FORCE_MAX_ZONEORDER int default "13" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) default "11" We can extend it later if people need this but I'm aiming for a single config on a multitude of boards. -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>