Re: [PATCH -v3 14/14] x86, mm: Map ISA area with connected ram rangeat the same time

From: Yinghai Lu
Date: Wed Sep 05 2012 - 14:57:10 EST


On Wed, Sep 5, 2012 at 1:02 AM, Pekka Enberg <penberg@xxxxxxxxxx> wrote:
>
> How significant is the speed gain? The "isa_done" flag makes code flow
> more difficult to follow.

Not really much.

when booting system:
memmap=16m$128m memmap=16m$512m memmap=16m$256m memmap=16m$768m memmap=16m$1024m

with the patch
[ 0.000000] init_memory_mapping: [mem 0x00000000-0x07ffffff]
[ 0.000000] [mem 0x00000000-0x07ffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x09000000-0x0fffffff]
[ 0.000000] [mem 0x09000000-0x0fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x11000000-0x1fffffff]
[ 0.000000] [mem 0x11000000-0x1fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x21000000-0x2fffffff]
[ 0.000000] [mem 0x21000000-0x2fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x31000000-0x3fffffff]
[ 0.000000] [mem 0x31000000-0x3fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x41000000-0x7fffdfff]
[ 0.000000] [mem 0x41000000-0x7fdfffff] page 2M
[ 0.000000] [mem 0x7fe00000-0x7fffdfff] page 4k


otherwise will have

[ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
[ 0.000000] [mem 0x00000000-0x000fffff] page 4k
[ 0.000000] init_memory_mapping: [mem 0x00100000-0x07ffffff]
[ 0.000000] [mem 0x00100000-0x001fffff] page 4k
[ 0.000000] [mem 0x00200000-0x07ffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x09000000-0x0fffffff]
[ 0.000000] [mem 0x09000000-0x0fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x11000000-0x1fffffff]
[ 0.000000] [mem 0x11000000-0x1fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x21000000-0x2fffffff]
[ 0.000000] [mem 0x21000000-0x2fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x31000000-0x3fffffff]
[ 0.000000] [mem 0x31000000-0x3fffffff] page 2M
[ 0.000000] init_memory_mapping: [mem 0x41000000-0x7fffdfff]
[ 0.000000] [mem 0x41000000-0x7fdfffff] page 2M
[ 0.000000] [mem 0x7fe00000-0x7fffdfff] page 4k
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