RE: [rfc] generic allocator and mspec driver

Luck, Tony
2005-02-14T19:12:54Z

>Anyway, it seems that lcrash at least only accesses the memory using
>read() and write()? which means it is relatively easy to using a
>struct page flag to do uncached vs cached access on the fly. mmap on
>the other hand would be a bit of a nightmare as it would require a
>custom fault handler that would know when to go cached and when not
>to.
>
>How would you feel about using PG_arch_1 for this on ia64?

Is ia64 the only architecture that has uncached vs. cached access
issues? If so, the PG_arch_1 might have to be the solution, but
surely others have cache coherence problems too if there are mixed
cacheable and uncacheable access to the same memory? In which case
a new generic bit would be more appropriate.

A few weeks back there was also some discussion about allocating
one or more bits to mark bad pages (those containing ECC errors)
as "do not touch".

-Tony