Messages in this thread | | | Date | Wed, 5 Sep 2012 11:02:33 +0300 | Subject | Re: [PATCH -v3 14/14] x86, mm: Map ISA area with connected ram range at the same time | From | Pekka Enberg <> |
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On Wed, Sep 5, 2012 at 8:46 AM, Yinghai Lu <yinghai@kernel.org> wrote: > so could reduce one loop. > > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
How significant is the speed gain? The "isa_done" flag makes code flow more difficult to follow.
> --- > arch/x86/mm/init.c | 21 ++++++++++++++------- > 1 files changed, 14 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 6663f61..e69f832 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -248,20 +248,27 @@ static void __init walk_ram_ranges( > void *data) > { > unsigned long start_pfn, end_pfn; > + bool isa_done = false; > int i; > > - /* the ISA range is always mapped regardless of memory holes */ > - work_fn(0, ISA_END_ADDRESS, data); > - > for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) { > u64 start = start_pfn << PAGE_SHIFT; > u64 end = end_pfn << PAGE_SHIFT; > > - if (end <= ISA_END_ADDRESS) > - continue; > + if (!isa_done && start > ISA_END_ADDRESS) { > + work_fn(0, ISA_END_ADDRESS, data); > + isa_done = true; > + } else { > + if (end < ISA_END_ADDRESS) > + continue; > + > + if (start <= ISA_END_ADDRESS && > + end >= ISA_END_ADDRESS) { > + start = 0; > + isa_done = true; > + } > + } > > - if (start < ISA_END_ADDRESS) > - start = ISA_END_ADDRESS; > #ifdef CONFIG_X86_32 > /* on 32 bit, we only map up to max_low_pfn */ > if ((start >> PAGE_SHIFT) >= max_low_pfn) > -- > 1.7.7 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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