Messages in this thread | | | Date | Wed, 24 Jul 2002 22:27:29 -0700 (PDT) | From | Linus Torvalds <> | Subject | RE: 2.5.28 and partitions |
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On Wed, 24 Jul 2002 Matt_Domsch@Dell.com wrote: > > The promise of 64-bit block addresses eventually was a huge part of why I > worked on the GPT code in the kernel, partx, parted, etc. I could really > use it today, and it'll be a solid requirement less than a year from now.
Note that there is one place where 64 bits is simply _too_ expensive, and that's the page cache. In particular, the "index" in "struct page". We want to make "struct page" _smaller_, not larger.
Right now that means that 16TB really is a hard limit for at least some device access on a 32-bit machine with a 4kB page-size (yes, you could make a filesystem that is bigger, but you very fundamentally cannot make individual files larger than 16TB).
The block device layer also cannot write to the 16TB+ region using the page cache (but it should be possible to do it using raw device access with a 64-bit sector_t, so you can initialize the filesystem).
Linus
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