Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait

From: Jens Axboe (
Date: Tue Feb 06 2001 - 19:35:23 EST

On Wed, Feb 07 2001, Stephen C. Tweedie wrote:
> > [overhead of 512-byte bhs in the raw IO code is an artificial problem of
> > the raw IO code.]
> No, it is a problem of the ll_rw_block interface: buffer_heads need to
> be aligned on disk at a multiple of their buffer size. Under the Unix
> raw IO interface it is perfectly legal to begin a 128kB IO at offset
> 512 bytes into a device.

Submitting buffers to lower layers that are not hw sector aligned
can't be supported below ll_rw_blk anyway (they can, but look at the
problems this has always created), and I would much rather see stuff
like this handled outside of there.

Jens Axboe

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