[linuxsh-dev] PCMCIA patch & question

[NIIBE Y. <gn...@ch...>]

Greg Banks wrote:
 >   This means that PCMCIA IO-space mappings are loaded
 > into the TLB in exactly the same way as other mappings.
 > In particular, wired TLB entries are *not* used.  But
 > the downside is a small number of extra instructions in
 > the main path for all TLB misses (PCMCIA and non-PCMCIA
 > alike).
 > 
 >   My question is, is this approach acceptable?  Is the
 > performance hit in the TLB miss handler worth freeing
 > up the TLB slots when PCMCIA is not being heavily used?

I think that wired TLB entry is better.  Some (or most) drivers don't
expect TLB fault would occur with I/O access functions.
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