On Fri, Feb 08, 2002 at 02:54:51PM -0800, Linus Torvalds wrote:
> bio can handle arbitrarily large IO's, BUT it can never split them.
I agree that it should not split ios, but it should not needlessly limit
the size of them either -- that choice should be left to individual
drivers.
...
> If you are in the small small _small_ minority care about 4MB requests,
> you should build the infrastructure not to make drivers split them, but
> to build up a list of bio's and then submit them all consecutively in
> one go.
>
> Remember: checking the limits as you build stuff up is easy, and fast.
>
> So you should make sure that you never EVER cause anybody to want to
> split a bio.
Yup. What we need is an interface for getting the max size of an io --
I can see this being needed for filesystems, char devices, network drivers,
basically anything that we can do aio/"direct" io on. Given that, I can
put the split / pipelining code into the generic layer.
-ben
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This archive was generated by hypermail 2b29 : Fri Feb 15 2002 - 21:00:24 EST