Messages in this thread | | | Subject | Re: [PATCH v2 3/6] x86, mm, asm-gen: Add ioremap_wt() for WT | From | Toshi Kani <> | Date | Wed, 10 Sep 2014 13:40:27 -0600 |
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On Wed, 2014-09-10 at 11:29 -0700, Andy Lutomirski wrote: > On Wed, Sep 10, 2014 at 9:51 AM, Toshi Kani <toshi.kani@hp.com> wrote: : > > +#ifndef ARCH_HAS_IOREMAP_WT > > +#define ioremap_wt ioremap_nocache > > +#endif > > + > > This is a little bit sad. I wouldn't be too surprised if there are > eventually users who prefer WC or WB over UC if WT isn't available > (and they'll want a corresponding way to figure out what kind of fence > to use).
Right, this redirection is not ideal for the performance, but it is done this way for the correctness. WT & UC have strongly ordered writes, but WB & WC do not.
Thanks, -Toshi
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