lkml.org 
[lkml]   [2013]   [May]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 0/2] vfio: type1 iommu hugepage support
From
Date
On Sat, 2013-05-25 at 07:21 -0400, Konrad Rzeszutek Wilk wrote:
> On Fri, May 24, 2013 at 11:24:26AM -0600, Alex Williamson wrote:
> > This series let's the vfio type1 iommu backend take advantage of iommu
> > large page support. See patch 2/2 for the details. This has been
> > tested on both amd_iommu and intel_iommu, but only my AMD system has
> > large page support. I'd appreciate any testing and feedback on other
> > systems, particularly vt-d systems supporting large pages. Mapping
> > efficiency should be improved a bit without iommu hugepages, but I
> > hope that it's much more noticeable with huge pages, especially for
> > very large QEMU guests.
>
> I took a very very quick look - and I am wondering if there should also
> be a flag to turn it on/off in ther kernel in such case? Especially in the
> field if a user finds out that their particular IOMMU chipset might
> be doing something funky with large-pages ?

Yeah, that's probably a reasonable feature. intel-iommu has a boot
option to disable superpages, but we could make it more consistent at
the vfio level if we have a switch there. It could provided interesting
performance and debugging info. I'll add a module option to do this.
Thanks,

Alex

> > This change includes a clarification to the mapping expectations for
> > users of the type1 iommu, but is compatible with known users and works
> > with existing QEMU userspace supporting vfio. Thanks,
> >
> > Alex
> >
> > ---
> >
> > Alex Williamson (2):
> > vfio: Convert type1 iommu to use rbtree
> > vfio: hugepage support for vfio_iommu_type1
> >
> >
> > drivers/vfio/vfio_iommu_type1.c | 607 ++++++++++++++++++++++++---------------
> > include/uapi/linux/vfio.h | 8 -
> > 2 files changed, 387 insertions(+), 228 deletions(-)
> > _______________________________________________
> > iommu mailing list
> > iommu@lists.linux-foundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/iommu





\
 
 \ /
  Last update: 2013-05-25 17:21    [W:0.574 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site