Re: [rfc] generic allocator and mspec driver

Jes Sorensen
2005-02-15T08:43:10Z

>>>>> "Tony" = Luck, Tony <tony.luck@intel.com> writes:

>> 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?

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

None of the ones I know well have this problem, but I have little
knowledge about this level of stuff on most architectures. The ones
that could have issues would probably be like PPC, PARISC and maybe
Alpha .....

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

Probably something which needs to be done sooner or later.

Cheers,
Jes