Re: [PATCH] bufq_priocscan enhancement

[Andrew Doran <ad%netbsd.org@localhost>]

I have not read the whole thread -- sorry.  I have a suggestion. If I were
to set out to make a dent on I/O performance, I would invest time in some
groundwork first:

- Stop abusing "struct buf" to describe I/O requests. Introduce an
  iorequest_t or something.

- Currently we do a virtual->physical->virtual->physical dance for many
  I/Os.  The process has quite a bit of overhead, and for many of those I/Os
  we won't need them to appear in kernel space hence the dance is not
  needed.  Make I/O requests pass around lists of vm_pages or physical
  addresses or whatever,