Use sparsemem as the only memory model for UP, SMP and NUMA.
Measurements indicate that DISCONTIGMEM has a higher
overhead than sparsemem. And FLATMEMs benefits are minimal. So I think its
best to simply standardize on sparsemem.
Results of page allocator tests (test can be had via git from the slab git
tree on git.kernel.org. See the branch tests)
Measurements in cycle counts. 1000 allocations were performed and then the
average cycle count was calculated.
Order FlatMem Discontig SparseMem
0 639 665 641
1 567 647 593
2 679 774 692
3 763 967 781
4 961 1501 962
5 1356 2344 1392
6 2224 3982 2336
7 4869 7225 5074
8 12500 14048 12732
9 27926 28223 28165
10 58578 58714 58682
If this patch is accepted then we can remove the code for discontig and
flatmem support from x86_64.
(Not sure if I got all the config settings right. Andy?)
Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>
---
arch/x86/Kconfig.x86_64 | 13 +------------
1 file changed, 1 insertion(+), 12 deletions(-)
Index: linux-2.6/arch/x86/Kconfig.x86_64
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig.x86_64 2007-11-12 15:17:50.721767735
-0800
+++ linux-2.6/arch/x86/Kconfig.x86_64 2007-11-12 15:21:16.659017509 -0800
@@ -390,28 +390,17 @@ config NUMA_EMU
into virtual nodes when booted with "numa=fake=N", where N is the
number of nodes. This is only useful for debugging.
-config ARCH_DISCONTIGMEM_ENABLE
- bool
- depends on NUMA
- default y
-
-config ARCH_DISCONTIGMEM_DEFAULT
+config ARCH_SPARSEMEM_DEFAULT
def_bool y
- depends on NUMA
config ARCH_SPARSEMEM_ENABLE
def_bool y
- depends on (NUMA || EXPERIMENTAL)
select SPARSEMEM_VMEMMAP_ENABLE
config ARCH_MEMORY_PROBE
def_bool y
depends on MEMORY_HOTPLUG
-config ARCH_FLATMEM_ENABLE
- def_bool y
- depends on !NUMA
-
source "mm/Kconfig"
config MEMORY_HOTPLUG_RESERVE
-
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