> -----Original Message----- > From: Matt Fleming [mailto:matt@xxxxxxxxxxxxxxxxxxx] > Sent: Monday, December 21, 2015 10:16 AM > To: Elliott, Robert (Persistent Memory) <elliott@xxxxxxx> > Cc: tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; hpa@xxxxxxxxx; x86@xxxxxxxxxx; > linux-efi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 4/4] x86/efi: print size and base in binary units in > efi_print_memmap > > 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. I was trying to make it resemble the memmap=size@address kernel parameter format for creating e820 entries, which does accept abbreviations in addition to hex values: memmap=nn[KMG]@ss[KMG] for usable DRAM memmap=nn[KMG]#ss[KMG] for ACPI data memmap=nn[KMG]$ss[KMG] for reserved memmap=nn[KMG]!ss[KMG] for persistent memory Mapping the UEFI type to the corresponding @, #, $, or ! was more than I wanted to tackle, so it's not a drop-in replacement string. memparse() also accepts T, P, and E units; I guess those need to be added to Documentation/kernel-parameters.txt. > > 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? Thanks for the pointer; I wondered if there was a similar function somewhere. However, that function throws away precision in favor of printing just 3 significant digits; I think that's dangerous. Its non-integer output is not supported by memmap=, and the function appears to use assembly code to get CPU divide instructions, losing the ability to use shifts for these power of two divisions. Example results... efi: mem01:... range=[0x0000000000093000-0x0000000000093fff] (4 KiB @ 588 KiB) efi: mem01:... range=[0x0000000000093000-0x0000000000093fff] (4.00 KiB @ 588 KiB) SGS efi: mem03:... range=[0x0000000000100000-0x00000000013e8fff] (19364 KiB @ 1 MiB) efi: mem03:... range=[0x0000000000100000-0x00000000013e8fff] (18.9 MiB @ 1.00 MiB) SGS (example of lost precision: 19364 KiB is really 18.91015625 MiB) efi: mem04:... range=[0x00000000013e9000-0x0000000001ffffff] (12380 KiB @ 20388 KiB) efi: mem04:... range=[0x00000000013e9000-0x0000000001ffffff] (12.0 MiB @ 19.9 MiB) SGS efi: mem28:... range=[0x00000000717c2000-0x0000000072acafff] (19492 KiB @ 1859336 KiB) efi: mem28:... range=[0x00000000717c2000-0x0000000072acafff] (19.0 MiB @ 1.77 GiB) SGS efi: mem57:... range=[0x0000000880000000-0x0000000e7fffffff] (24 GiB @ 34 GiB) efi: mem57:... range=[0x0000000880000000-0x0000000e7fffffff] (24.0 GiB @ 34.0 GiB) SGS --- Robert Elliott, HPE Persistent Memory -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
