Messages in this thread | | | Date | Mon, 31 Aug 2009 10:26:32 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: reuse the boot-time mappings of fixed_addresses |
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* H. Peter Anvin <hpa@zytor.com> wrote:
> Ingo Molnar wrote: >> * Xiao Guangrong <ericxiao.gr@gmail.com> wrote: >> >>> From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> >>> >>> Some fixed_addresses items are only used when system boot, after >>> boot, they are free but no way to use, like early ioremap area. They >>> are wasted for us, we can reuse them after system boot. >>> >>> In this patch, we put them in permanent kmap's area and expand >>> vmalloc's address range. In boot time, reserve them in >>> permanent_kmaps_init() to avoid multiple used, after system boot, we >>> unreserved them then user can use it. >>> >>> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> >>> --- >>> arch/x86/include/asm/fixmap.h | 2 ++ >>> arch/x86/include/asm/pgtable_32_types.h | 4 ++-- >>> arch/x86/mm/init_32.c | 8 ++++++++ >>> include/linux/highmem.h | 2 ++ >>> mm/highmem.c | 26 ++++++++++++++++++++++++++ >>> 5 files changed, 40 insertions(+), 2 deletions(-) >> >> I'm wondering, how much space do we save this way, on a typical bootup >> on a typical PC? >> > > Not a huge lot... a few dozen pages.
I guess it's still worth doing - what do you think?
Ingo
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