On Sun, 28 Jul 2002, Anton Altaparmakov wrote:
>
> Why should I need to bother with index/offset? It is much more natural to
> work with bytes.
Two major reasons:
- the page cache works with index/offset, and that should be your first
priority, since the page cache is all that matters from a performance
standpoint.
- gcc is known to be broken with 64-bit stuff on 32-bit platforms, and
minimizing the use of "long long" minimizes the risk of hitting bugs.
> Also the page cache limit of 32-bit index is IMO not good and needs to be
> removed.
Dream on. It's good, and it's not getting removed. The "struct page" is
size-critical, and also correctness-critical (see above on gcc issues).
We're not moving to a 64-bit index for the next few years. We're a lot
more likely to make PAGE_SIZE bigger, and generally praying that AMD's
x86-64 succeeds in the market, forcing Intel to make Yamhill their
standard platform. At which point we _could_ make things truly 64 bits
(the size pressure on "struct page" is largely due to HIGHMEM, and gcc
does fine on 64-bit platforms).
But that's certainly years away.
Linus
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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:31 EST