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SubjectRe: [PATCH] jffs2: implement mount option to configure endianness
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On Wed, 2018-11-07 at 17:58 +0000, David Woodhouse wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
> > On Wed, Nov 07, 2018 at 04:12:14PM -0000, David Woodhouse wrote:
> > > > Yes, this may slow things down. I am not sure I agree with the impl.
> > > > either.
> > > > Could one not make cpu_to_je_X/jeX_to_cpu a function ptr which is set
> > > to
> > > > a func. with the correct endian?
> > >
> > > On x86 retpoline would make that quite slow.

retpoline aside, would it make a difference ?

> >
> > Is x86 the largest consumer of jffs2 ?
>
> Certainly not. I'm not sure which architectures do have Spectre V2
> mitigations which make indirect branches expensive now... perhaps there is
> no intersection with the cases where we really care about JFFS2 being
> CPU-bound?

All that passing of a new extra arg and extra if .. elif .. does cost too.
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