On Tue, 16 Oct 2018, tedheadster wrote:
> On Sun, Oct 14, 2018 at 3:52 AM Christoph Hellwig <[email protected]> wrote:
> >
> > We already build the swiotlb code for 32b-t kernels with PAE support,
> > but the code to actually use swiotlb has only been enabled for 64-bit
> > kernel for an unknown reason.
> >
> > Before Linux 4.18 we papers over this fact because the networking code,
> > the scsi layer and some random block drivers implenented their own
> > bounce buffering scheme.
> >
> > Fixes: 21e07dba ("scsi: reduce use of block bounce buffers")
> > Fixes: ab74cfeb ("net: remove the PCI_DMA_BUS_IS_PHYS check in
> > illegal_highdma")
> > Reported-by: tedheadster <[email protected]>
> > Tested-by: tedheadster <[email protected]>
> > ---
> >
>
> Christoph,
> this fix has causes performance to decrease dramatically. Kernel
> builds that used to take 10-15 minutes are now taking 45-60 minutes on
> the same machine.
Christoph, can you have a look please?
Thanks,
tglx
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