Messages in this thread | | | Date | Sat, 29 Aug 2009 11:16:40 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: reuse the boot-time mappings of fixed_addresses |
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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.
-hpa
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