On Wed, 2007-11-21 at 09:39 +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2007-11-20 at 15:10 -0600, James Bottomley wrote:
> > We're talking about trying to fix this for 2.4; which is already at
> > -rc3 ... Is an entire arch change for dma alignment really a merge
> > candidate at this stage?
>
On Tue, 2007-11-20 at 15:10 -0600, James Bottomley wrote:
> We're talking about trying to fix this for 2.4; which is already at
> -rc3 ... Is an entire arch change for dma alignment really a merge
> candidate at this stage?
Well, as I said before... it's a matter of what seems to be the less
like
On Tue, 2007-11-20 at 12:05 -0800, Roland Dreier wrote:
> > Actually, we already established on IRC that the lasi700 driver doesn't
> > need this, principally because the parisc architecture doesn't do an
> > invalidate for DMA_FROM_DEVICE but a flush and invalidate
> > (architecturally, if you
> Actually, we already established on IRC that the lasi700 driver doesn't
> need this, principally because the parisc architecture doesn't do an
> invalidate for DMA_FROM_DEVICE but a flush and invalidate
> (architecturally, if you read our manuals, even pdc is entitled to write
> back dirty l
On Tue, 2007-11-20 at 14:14 +1100, Benjamin Herrenschmidt wrote:
> FYI, Here's what I have for the SCSI change. I haven't updated drivers
> to care for the new return code though, help appreciated with that as I
> don't know much about these drivers.
It looks to me like the return problem could b
On Tue, 2007-11-20 at 09:29 +0100, Thomas Bogendoerfer wrote:
> On Tue, Nov 20, 2007 at 06:51:14AM +1100, Benjamin Herrenschmidt wrote:
> >
> > On Mon, 2007-11-19 at 00:38 -0800, David Miller wrote:
> > > From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> > > Date: Mon, 19 Nov 2007 16:35:23 +1100
On Tue, Nov 20, 2007 at 06:51:14AM +1100, Benjamin Herrenschmidt wrote:
>
> On Mon, 2007-11-19 at 00:38 -0800, David Miller wrote:
> > From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> > Date: Mon, 19 Nov 2007 16:35:23 +1100
> >
> > > I'm not sure what is the best way to fix that. Internally, I'
FYI, Here's what I have for the SCSI change. I haven't updated drivers
to care for the new return code though, help appreciated with that as I
don't know much about these drivers.
Index: linux-work/drivers/scsi/scsi_error.c
===
--- li
On Mon, 2007-11-19 at 18:10 -0800, Roland Dreier wrote:
>
> I wrapped this ugliness up inside the macro back in what I posted in
> 2002 (http://lkml.org/lkml/2002/6/12/234):
>
> #define __dma_buffer __dma_buffer_line(__LINE__)
> #define __dma_buffer_line(line) __dma_buffer_expand_line(line)
> #d
> 2) Add the __dma_cacheline_aligned tag.
>
> But note that with #2 it could get quite ugly because the
> alignment and size both have a minimum that needs to be
> enforced, not just the alignment alone. So either:
>
> struct foo {
> unsigned int other_unrelated_stuff;
>
> s
From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Date: Tue, 20 Nov 2007 11:55:01 +1100
> BTW. What is the status nowadays with skb's ?
Good question.
Some drivers are problematic (or were) because they put
DMA descriptor chaining information at the head of the
buffer, but those have been fixed e
On Mon, 2007-11-19 at 16:46 -0800, David Miller wrote:
>
> 1) Require that entire buffers are commited by call sites,
>and thus "embedding" DMA'd within non-DMA stuff isn't allowed
>
> 2) Add the __dma_cacheline_aligned tag.
>
> But note that with #2 it could get quite ugly because the
> al
From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Date: Tue, 20 Nov 2007 11:34:24 +1100
> Do you still think we should introduce this __dma_cacheline_aligned ? Do
> you see other cases of drivers where it would be useful ? It tend to
> agree with your earlier statement that drivers doing that are b
On Mon, 2007-11-19 at 14:31 -0800, David Miller wrote:
> From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> Date: Tue, 20 Nov 2007 06:51:14 +1100
>
> > On Mon, 2007-11-19 at 00:38 -0800, David Miller wrote:
> > > From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> > > Date: Mon, 19 Nov 2007 16:35:
From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Date: Tue, 20 Nov 2007 06:51:14 +1100
> On Mon, 2007-11-19 at 00:38 -0800, David Miller wrote:
> > From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> > Date: Mon, 19 Nov 2007 16:35:23 +1100
> >
> > You could make a dma_cacheline_aligned and use
On Mon, 2007-11-19 at 13:43 -0800, Roland Dreier wrote:
> > I've been debugging various issues on the PowerPC 44x embedded
> > architecture which happens to have non-coherent PCI DMA.
> >
> > One of the problem I'm hitting is that one really need to enforce
> > kmalloc alignement to cache lin
> I've been debugging various issues on the PowerPC 44x embedded
> architecture which happens to have non-coherent PCI DMA.
>
> One of the problem I'm hitting is that one really need to enforce
> kmalloc alignement to cache lines or bad things will happen (among
> others with USB), for some
> I'd like to be rid of it inside the command for various reasons: every
> command has one of these, and they're expensive in the allocation (at 96
> bytes). There's no reason we have to allocate and free that amount of
> space with every command. In theory, the number of these is bounded at
>
On Mon, 2007-11-19 at 09:09 -0600, James Bottomley wrote:
> > What other drivers do is DMA to their own allocation and then memcpy to
> > the sense buffer.
> >
> > There is a movement to allocate the sense data as its own sg list, but
> > I don't think that patch has even been posted yet.
>
> I'
On Mon, 2007-11-19 at 05:32 -0700, Matthew Wilcox wrote:
> On Mon, Nov 19, 2007 at 04:35:23PM +1100, Benjamin Herrenschmidt wrote:
> > The other one I'm hitting now is that the SCSI layer nowadays embeds the
>
> 'nowadays'? It has always been so.
Wasn't it kmalloc'ed at one point ?
> > sense_b
On Mon, 2007-11-19 at 00:38 -0800, David Miller wrote:
> From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
> Date: Mon, 19 Nov 2007 16:35:23 +1100
>
> > I'm not sure what is the best way to fix that. Internally, I've done
> > some test whacking some cacheline_aligned in the scsi_cmnd data
> >
On Mon, 2007-11-19 at 05:32 -0700, Matthew Wilcox wrote:
> On Mon, Nov 19, 2007 at 04:35:23PM +1100, Benjamin Herrenschmidt wrote:
> > The other one I'm hitting now is that the SCSI layer nowadays embeds the
>
> 'nowadays'? It has always been so.
>
> > sense_buffer inside the scsi_cmnd structur
On Mon, Nov 19, 2007 at 04:35:23PM +1100, Benjamin Herrenschmidt wrote:
> The other one I'm hitting now is that the SCSI layer nowadays embeds the
'nowadays'? It has always been so.
> sense_buffer inside the scsi_cmnd structure without any kind of
> alignment whatsoever. I've been hitting irregu
From: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Date: Mon, 19 Nov 2007 16:35:23 +1100
> I'm not sure what is the best way to fix that. Internally, I've done
> some test whacking some cacheline_aligned in the scsi_cmnd data
> structure to verify I no longer get random SLAB corruption when usin
Hi James !
(Please CC me on replies as I'm not subscribed to linux-scsi)
I've been debugging various issues on the PowerPC 44x embedded
architecture which happens to have non-coherent PCI DMA.
One of the problem I'm hitting is that one really need to enforce
kmalloc alignement to cache lines or
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