Re: [PATCH 00/13] mmu_notifier kill invalidate_page callback

From: Jerome Glisse <jglisse@redhat.com>
To: Felix Kuehling <felix.kuehling@amd.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
	"Christian König" <christian.koenig@amd.com>,
	amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH 00/13] mmu_notifier kill invalidate_page callback
Date: Thu, 31 Aug 2017 19:29:52 -0400	[thread overview]
Message-ID: <20170831232951.GB20888@redhat.com> (raw)
In-Reply-To: <9a76dd3e-e266-c77e-721a-379092d714f1@amd.com>

On Thu, Aug 31, 2017 at 07:19:19PM -0400, Felix Kuehling wrote:
> On 2017-08-31 03:00 PM, Jerome Glisse wrote:
> > I was not saying you should not use mmu_notifier. For achieving B you need
> > mmu_notifier. Note that if you do like ODP/KVM then you do not need to
> > pin page.
> I would like that. I've thought about it before. The one problem I
> couldn't figure out is, where to set the accessed and dirty bits for the
> pages. Now we do it when we unpin. If we don't pin the pages in the
> first place, we don't have a good place for this.
> 
> Our hardware doesn't give us notifications or accessed/dirty bits, so we
> have to assume the worst case that the pages are continuously
> accessed/dirty.
> 
> I'd appreciate any advice how to handle that. (Sorry, I realize this is
> going a bit off topic.) A pointer to a document or source code would be
> great. :)

In invalidate_range_start() ie same place as where you unpin but instead
of unpining you would just call set_page_dirty()

Jérôme
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