Messages in this thread | | | Date | Thu, 18 Sep 2008 12:13:38 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 03/23] AMD IOMMU: implement lazy IO/TLB flushing |
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On Thu, Sep 18, 2008 at 10:29:24AM +0900, FUJITA Tomonori wrote: > On Wed, 17 Sep 2008 21:28:27 +0200 > Joerg Roedel <joro@8bytes.org> wrote: > > > On Thu, Sep 18, 2008 at 04:20:18AM +0900, FUJITA Tomonori wrote: > > > On Wed, 17 Sep 2008 18:52:37 +0200 > > > Joerg Roedel <joerg.roedel@amd.com> wrote: > > > > > > > The IO/TLB flushing on every unmaping operation is the most expensive > > > > part there and not strictly necessary. It is sufficient to do the flush > > > > before any entries are reused. This is patch implements lazy IO/TLB > > > > flushing which does exactly this. > > > > > > > > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> > > > > --- > > > > Documentation/kernel-parameters.txt | 5 +++++ > > > > arch/x86/kernel/amd_iommu.c | 26 ++++++++++++++++++++++---- > > > > arch/x86/kernel/amd_iommu_init.c | 10 +++++++++- > > > > include/asm-x86/amd_iommu_types.h | 9 +++++++++ > > > > 4 files changed, 45 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > > > > index c2e00ee..5f0aefe 100644 > > > > --- a/Documentation/kernel-parameters.txt > > > > +++ b/Documentation/kernel-parameters.txt > > > > @@ -284,6 +284,11 @@ and is between 256 and 4096 characters. It is defined in the file > > > > isolate - enable device isolation (each device, as far > > > > as possible, will get its own protection > > > > domain) > > > > + unmap_flush - enable flushing of IO/TLB entries when > > > > + they are unmapped. Otherwise they are > > > > + flushed before they will be reused, which > > > > + is a lot of faster > > > > + > > > > > > Would it be nice to have consistency of IOMMU parameters? > > > > True. We should merge common parameters across IOMMUs into the > > iommu= parameter some time in the future, I think. It would also be the > > place for the IOMMU size parameter. > > Hmm, now is better than the future? I think that now you can add > something like 'disable_batching_flush' as a common parameter and > change AMD IOMMU to use it.
Ok, I introduce a parameter called '[no]fullflush' like the GART already uses. We can remove this parameter from gart_parse_options() later then.
Joerg
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