Re: CVS commit: [tls-maxphys] src/sys/dev

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Tue, Oct 09, 2012 at 03:50:18PM +0200, Manuel Bouyer wrote:
> On Tue, Oct 09, 2012 at 01:36:07PM +0000, Manuel Bouyer wrote:
> > [...]
> > Log Message:
> > Support transfers of up to MACHINE_MAXPHYS in all pciide variants, and ahci.
> > wd(4) limits its maxphys depending on the drives's capability (64k sectors
> > for LBA48, 256 sectors for LBA and 128 sectors for older devices).
> > 
> > I assumed all pciide controllers could do MACHINE_MAXPHYS transfers, but
> > this may not be true. The capabilities of each controller variants should be
> > looked at more closely.
> 
> transfers with dd on the raw character device works fine, but I get this
> panic when booting multiuser, both with pciide and ahci controllers:
> Starting ntpd.
> panic: bad chunksize 139264, iochunk 524288, request size 139264

Hmmmmm.

This will be an attempt to transfer an entire file -- 139264 will be the
entire file size of something, probably an executable it's paging in.

I saw this before -- I can't remember what caused it -- the "bad chunksize"
is, I think, because it's not power-of-2.  The cause will be in the UVM
readahead code.

I could swear I fixed at least one cause of this already.

Thor