linux/arch/x86_64
Christoph Lameter 5ac6da669e [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA
As Andi pointed out: CONFIG_GENERIC_ISA_DMA only disables the ISA DMA
channel management.  Other functionality may still expect GFP_DMA to
provide memory below 16M.  So we need to make sure that CONFIG_ZONE_DMA is
set independent of CONFIG_GENERIC_ISA_DMA.  Undo the modifications to
mm/Kconfig where we made ZONE_DMA dependent on GENERIC_ISA_DMA and set
theses explicitly in each arches Kconfig.

Reviews must occur for each arch in order to determine if ZONE_DMA can be
switched off.  It can only be switched off if we know that all devices
supported by a platform are capable of performing DMA transfers to all of
memory (Some arches already support this: uml, avr32, sh sh64, parisc and
IA64/Altix).

In order to switch ZONE_DMA off conditionally, one would have to establish
a scheme by which one can assure that no drivers are enabled that are only
capable of doing I/O to a part of memory, or one needs to provide an
alternate means of performing an allocation from a specific range of memory
(like provided by alloc_pages_range()) and insure that all drivers use that
call.  In that case the arches alloc_dma_coherent() may need to be modified
to call alloc_pages_range() instead of relying on GFP_DMA.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:19 -08:00
..
boot [PATCH] x86-64: shorten the x86_64 boot setup GDT to what the comment says 2006-11-14 16:57:46 +01:00
crypto [CRYPTO] api: Get rid of flags argument to setkey 2006-09-21 11:41:02 +10:00
ia32 [PATCH] x86_64 ia32 vDSO: use install_special_mapping 2007-02-09 09:25:47 -08:00
kernel Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6 2007-02-07 19:23:44 -08:00
lib [PATCH] x86-64: Don't force inlining of do_csum 2006-12-07 02:14:07 +01:00
mm ACPICA: Remove duplicate table definitions (non-conflicting), cont 2007-02-02 21:14:29 -05:00
oprofile [PATCH] Move Kprobes and Oprofile to "Instrumentation Support" menu 2005-11-07 07:53:35 -08:00
pci ACPICA: Remove duplicate table definitions (non-conflicting), cont 2007-02-02 21:14:29 -05:00
defconfig [PATCH] x86-64: Update defconfig 2007-01-11 01:52:44 +01:00
Kconfig [PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA 2007-02-11 10:51:19 -08:00
Kconfig.debug [PATCH] lockdep: irqtrace subsystem, x86_64 support 2006-07-03 15:27:03 -07:00
Makefile Remove stack unwinder for now 2006-12-15 08:47:51 -08:00