Re: [PATCH 4/4] x86/efi: print size and base in binary units in efi_print_memmap

From: Matt Fleming
Date: Mon Dec 21 2015 - 11:16:36 EST


On Thu, 17 Dec, at 07:28:34PM, Robert Elliott wrote:
> Print the base address for each range in decimal alongside the size.
> Use a "(size @ base)" format similar to the fake_memmap kernel parameter.
>
> Print the range and base in the best-fit B, KiB, MiB, etc. units rather
> than always MiB. This avoids rounding, which can be misleading.
>
> Use proper IEC binary units (KiB, MiB, etc.) rather than misuse SI
> decimal units (KB, MB, etc.).
>
> old:
> efi: mem61: [Persistent Memory | | | | | | | |WB|WT|WC|UC] range=[0x0000000880000000-0x0000000c7fffffff) (16384MB)
>
> new:
> efi: mem61: [Persistent Memory | | | | | | | |WB|WT|WC|UC] range=[0x0000000880000000-0x0000000c7fffffff] (16 GiB @ 34 GiB)
>
> Signed-off-by: Robert Elliott <elliott@xxxxxxx>
> ---
> arch/x86/platform/efi/efi.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)

I'm not at all sure of the value of printing the physical address as a
size. I would have thought that you'd have to convert it back to an
address whenever you wanted to use it anyway.

> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 635a955..030ba91 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -222,6 +222,25 @@ int __init efi_memblock_x86_reserve_range(void)
> return 0;
> }
>
> +char * __init efi_size_format(char *buf, size_t size, u64 bytes)
> +{
> + if (!bytes || (bytes & 0x3ff))
> + snprintf(buf, size, "%llu B", bytes);
> + else if (bytes & 0xfffff)
> + snprintf(buf, size, "%llu KiB", bytes >> 10);
> + else if (bytes & 0x3fffffff)
> + snprintf(buf, size, "%llu MiB", bytes >> 20);
> + else if (bytes & 0xffffffffff)
> + snprintf(buf, size, "%llu GiB", bytes >> 30);
> + else if (bytes & 0x3ffffffffffff)
> + snprintf(buf, size, "%llu TiB", bytes >> 40);
> + else if (bytes & 0xfffffffffffffff)
> + snprintf(buf, size, "%llu PiB", bytes >> 50);
> + else
> + snprintf(buf, size, "%llu EiB", bytes >> 60);
> + return buf;
> +}
> +

Can we use string_get_size() instead of rolling our own function?
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