Messages in this thread Patch in this message | | | Date | Wed, 17 Aug 2011 12:37:17 +0200 | From | Borislav Petkov <> | Subject | Re: [tip:x86/mm] x86, mm: Allow ZONE_DMA to be configurable |
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On Mon, May 16, 2011 at 11:13:07PM +0000, tip-bot for David Rientjes wrote: > Commit-ID: dc382fd5bcca7098a984705ed6ac880f539d068e > Gitweb: http://git.kernel.org/tip/dc382fd5bcca7098a984705ed6ac880f539d068e > Author: David Rientjes <rientjes@google.com> > AuthorDate: Mon, 16 May 2011 13:54:10 -0700 > Committer: H. Peter Anvin <hpa@linux.intel.com> > CommitDate: Mon, 16 May 2011 14:03:28 -0700 > > x86, mm: Allow ZONE_DMA to be configurable > > ZONE_DMA is unnecessary for a large number of machines that do not > require less than 32-bit DMA addressing, e.g. ISA legacy DMA or PCI > cards with a restricted DMA address mask. > > This patch allows users to disable ZONE_DMA for x86 if they know they > will not be using such devices with their kernel. > > This prevents the VM from unnecessarily reserving a ratio of memory > (defaulting to 1/256th of system capacity) with lowmem_reserve_ratio > for such allocations when it will never be used. > > Signed-off-by: David Rientjes <rientjes@google.com> > Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1105161353560.4353@chino.kir.corp.google.com > Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This causes the ZONE_DMA menu option to appear in the toplevel menu of the kernel configurator instead of under EXPERT, where it should belong IMO.
> --- > arch/x86/Kconfig | 9 ++++++++- > arch/x86/mm/init_32.c | 2 ++ > arch/x86/mm/init_64.c | 2 ++ > 3 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 648fca4..0eb801a 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -112,7 +112,14 @@ config MMU > def_bool y > > config ZONE_DMA > - def_bool y > + bool "DMA memory allocation support" if EXPERT > + default y > + help > + DMA memory allocation support allows devices with less than 32-bit > + addressing to allocate within the first 16MB of address space. > + Disable if no such devices will be used. > + > + If unsure, say Y.
maybe this should go into init/Kconfig ?
Thanks.
-- Regards/Gruss, Boris.
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