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

From: Andy Shevchenko
Date: Sun Dec 27 2015 - 09:35:23 EST


On Mon, Dec 21, 2015 at 6:16 PM, Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:
> 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;

For me it looks like ffs with name in the table can be used.

>> +}
>> +
>
> Can we use string_get_size() instead of rolling our own function?
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--
With Best Regards,
Andy Shevchenko
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