lkml.org 
[lkml]   [2002]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: 2.5.32 IO performance issues
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.

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.
-- Patrick Mansfield
-
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/

\
 
 \ /
  Last update: 2005-03-22 13:28    [W:0.041 / U:1.956 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site