Messages in this thread |  | | Date | Thu, 29 Aug 2002 15:23:24 -0700 | From | Andrew Morton <> | Subject | Re: 2.5.32 IO performance issues |
| |
Patrick Mansfield wrote: > > On Thu, Aug 29, 2002 at 01:55:40PM -0700, Badari Pulavarty wrote: > > > > > > block-highmem is bust for scsi. (aic7xxx at least). Does > > > http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.32/2.5.32-mm2/broken-out/scsi_hack.patch > > > fix it? > > > > Hmm !! This patch fixed it. I remember you gave me this patch for 2.5.31. But 2.5.31 > > was doing fine without it. But 2.5.32 seem to need it. > > > > The above patch works fine to get back to the previous (pre-2.5.32) state. > But, it makes no sense to modify the bounce_limit based on the type of > storage that is attached to an adapter.
I agree. Hence the name "scsi_hack" ;)
> We want to allow high mem for block devices other than SCSI direct access > devices (TYPE_DISK), such as CD ROM (SDpnt->type TYPE_ROM), WORM devices > (TYPE_WORM), and optical disks (TYPE_MOD). > > So it is better to patch scsi_initialize_merge_fn: > > --- 1.16/drivers/scsi/scsi_merge.c Fri Jul 5 09:43:00 2002 > +++ edited/drivers/scsi/scsi_merge.c Thu Aug 29 14:30:12 2002 > @@ -140,7 +140,7 @@ > * Enable highmem I/O, if appropriate. > */ > bounce_limit = BLK_BOUNCE_HIGH; > - if (SHpnt->highmem_io && (SDpnt->type == TYPE_DISK)) { > + if (SHpnt->highmem_io) { > if (!PCI_DMA_BUS_IS_PHYS) > /* Platforms with virtual-DMA translation > * hardware have no practical limit. >
That will certainly fix it. But who added the TYPE_DISK check, and why??? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |