Re: [PATCH v3] storvsc: use small sg_tablesize on x86

From: Olaf Hering
Date: Thu Jun 09 2016 - 18:01:35 EST


On Thu, Jun 09, James Bottomley wrote:

> On Thu, 2016-06-09 at 18:25 +0200, Olaf Hering wrote:
> > Reducing the sg_tablesize allows booting of 32bit kernels in VMs,
> > after
> > commit be0cf6ca301c61458dc4aa1a37acf4f58d2ed3d6 ("scsi: storvsc: Set
> > the
> > tablesize based on the information given by the host")
> >
> > [ 5.567138] hv_storvsc vmbus_1: adjusting sg_tablesize 0x800 ->
> > 0x20
>
> Are you really sure 32 is the correct size?

Its a size that works, while the current state does not work at all.

> I know 32 it what it had before, but the reason for the commit you
> quote was to improve performance ...

The commit above broke 32bit. Whoever wants to improve performance on
this dead horse can submit another patch.

Olaf