Re: [PATCH][RFC]: pte notifiers -- support for external page tables

From: Avi Kivity
Date: Wed Sep 05 2007 - 16:45:45 EST


[resend due to broken cc list in my original post]

Jack Steiner wrote:
On Wed, Sep 05, 2007 at 07:38:48PM +0300, Avi Kivity wrote:
Some hardware and software systems maintain page tables outside the normal
Linux page tables, which reference userspace memory. This includes
Infiniband, other RDMA-capable devices, and kvm (with a pending patch).


I like it.

We have 2 special devices with external TLBs that can
take advantage of this.

One suggestion - at least for what we need. Can the notifier be
registered against the mm_struct instead of (or in addition to) the
vma?

Yes. It's a lot simpler since this way we don't have to support vma
creation/splitting/merging/destruction. There's a tiny performance hit
for kvm, but it isn't worth the bother.

Will implement for v2 of this patch.

--
Any sufficiently difficult bug is indistinguishable from a feature.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/