On Thursday 12 March 2009 23:32:30 Matthew Wilcox wrote: > On Thu, Mar 12, 2009 at 05:24:33AM -0700, Daniel Phillips wrote: > > On Thursday 12 March 2009, Nick Piggin wrote: > > > That's interesting. Do you handle 1K block sizes with 64K page size? :) > > > > Not in its current incarnation. That would require 32 bytes worth of > > state while the current code just has a 4 byte map (4 bits X 8 blocks). > > I suppose a reasonable way to extend it would be 4 x 8 byte maps. Has > > somebody spotted a 64K page? > > I believe SGI ship their ia64 kernels configured this way. Certainly > 16k ia64 kernels are common, which would (if I understand your scheme > correctly) be 8 bytes worth of state in your scheme. I think some distros will (or do) ship configs with 64K page size for ia64 and powerpc too. I think I have heard of people using 64K pages with ARM. There was some (public) talk of x86-64 getting a 16K or 64K page size too (and even if not HW, some people want to be able to go bigger SW pagecache size). I wouldn't expect 64K page and 1K block to be worth optimising for (although 64K page systems could easily use older or shared 4K block filesystems). But just keep in mind that a good solution should not rely on PAGE_CACHE_SIZE for correctness. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
