From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
Subject: Re: [PATCH v3 3/4] x86/efi: print size in binary units in
 efi_print_memmap
Date: Thu, 28 Jan 2016 09:29:59 +0000
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Cc: "Elliott, Robert (Persistent Memory)" <elliott-ZPxbGqLxI0U@public.gmane.org>, Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, James Bottomley <James.Bottomley-JuX6DAaQMKPCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Rasmus Villemoes <linux-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, "linux-kernel @ vger . kernel . org" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
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On Tue, 26 Jan, at 01:59:26PM, Andy Shevchenko wrote:
> On Tue, 2016-01-26 at 11:50 +0000, Matt Fleming wrote:
> > On Mon, 25 Jan, at 08:37:58PM, Elliott, Robert (Persistent Memory)
> > wrote:
> > >=20
> > > For the UEFI memory map, that was indeed my intention.=A0=A0I
> > > don't want it silently round to "20 GiB".=A0=A0Even rounding
> > > to "19.999 GiB" is imprecise.
> >=20
> > OK, let's just go with your original patch Robert (minus the @ addr
> > bit) since it's pretty small and does what we want for this specifi=
c
> > case.
>=20
> However I am against this, but seems reviewers do not leave a chance =
to
> us, I would propose to copy-and-paste table of binary prefixes and us=
e
> __ffs64().

Is there a benefit to this approach other than __ffs64() being faster?
It is a neglibible performance gain anyway because this is hidden
behind efi=3Ddebug, and so by definition you're not looking for ultra
performance.

Which makes picking between __ffs64() and non-__ffs64() a wash if
we're not going to be reusing existing code.