Re: [GIT PULL] AMD IOMMU updates for 2.6.28

[FUJITA Tomonori]

On Fri, 19 Sep 2008 13:02:40 +0200
Joerg Roedel <joerg.roedel@xxxxxxx> wrote:

> On Fri, Sep 19, 2008 at 07:51:11PM +0900, FUJITA Tomonori wrote:
> > On Fri, 19 Sep 2008 12:39:23 +0200
> > Joerg Roedel <joerg.roedel@xxxxxxx> wrote:
> > 
> > > On Fri, Sep 19, 2008 at 07:28:13PM +0900, FUJITA Tomonori wrote:
> > > > On Fri, 19 Sep 2008 12:07:11 +0200
> > > > Joerg Roedel <joerg.roedel@xxxxxxx> wrote:
> > > > 
> > > > > Hi Ingo,
> > > > > 
> > > > > please pull the updates for the AMD IOMMU driver for the 2.6.28 merge
> > > > > window. Most of the patches had been sent to LKML for review and got
> > > > > comments. One patch touches the GART driver and was added after an
> > > > > objection with a patch previously in this series. Please pull.
> > > > > 
> > > > > The following changes since commit 74546a8cd9a4e2c26a15a534f0be2f9cc08ae675:
> > > > >   Ingo Molnar (1):
> > > > >         Revert "fix warning in: "x86: HPET_MSI Initialise per-cpu HPET timers""
> > > > > 
> > > > > are available in the git repository at:
> > > > > 
> > > > >   git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu.git iommu-updates-2.6.28
> > > > > 
> > > > > FUJITA Tomonori (1):
> > > > >       AMD IOMMU: avoid unnecessary low zone allocation in alloc_coherent
> > > > > 
> > > > > Joerg Roedel (24):
> > > > >       AMD IOMMU: check for invalid device pointers
> > > > >       AMD IOMMU: move TLB flushing to the map/unmap helper functions
> > > > >       x86: move GART TLB flushing options to generic code
> > > > 
> > > > As I wrote, I don't think that this GART patch is the right approach.
> > > 
> > > I don't thinks its clean to leave nofullflush in GART code and move
> > > fullflush to generic code only.
> > 
> > It's not clean for GART but clean for other IOMMUs.
> 
> So its unclean anyway. It doesn't matter if for GART or for AMD IOMMU.
> 
> > > If we move something then both. But feel
> > > free to submit a patch that removes the nofullflush option. I would not
> > > disagree with that.
> > 
> > I'm not sure we can remove an option that we added. If we can, please
> > remove it now. There is no point to make the meaningless option
> > generic.
> 
> I don't added this option. I just moved it to generic code from the

You added it to the generic place. Moving it to the generic place
means adding it to the generic place.

There is no difference in the end. Now 'nofullflush' is listed as the
generic place.

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c2e00ee..569527e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -888,6 +888,10 @@ and is between 256 and 4096 characters. It is defined in the file
 		nomerge
 		forcesac
 		soft
+		fullflush
+			Flush IO/TLB at every deallocation
+		nofullflush
+			Flush IO/TLB only when addresses are reused (default)


Please don't do that.


> GART. The nofullflush option has no meaning for GART and for AMD
> IOMMU. The only reason to keep it is if we want to change the default in
> the future.

No, we can't change the default behavior. It's the user interface.


> If you don't think we would change the default any time in
> the future feel free to remove it.
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