| Message ID | 1367339448-21727-9-git-send-email-steve.capper@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@linaro.org> > --- > 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.
On Thu, May 02, 2013 at 11:00:00AM +0100, Catalin Marinas wrote: > On Tue, Apr 30, 2013 at 05:30:47PM +0100, Steve Capper wrote: > 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 Thanks, that does look a lot neater :-).
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) + help + The kernel memory allocator divides physically contiguous memory + blocks into "zones", where each zone is a power of two number of + pages. This option selects the largest power of two that the kernel + keeps in the memory allocator. If you need to allocate very large + blocks of physically contiguous memory, then you may need to + increase this value. + + This config option is actually maximum order plus one. For example, + a value of 11 means that the largest free memory block is 2^10 pages. + endmenu menu "Boot options"
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@linaro.org> --- arch/arm64/Kconfig | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)