From: Jason Gunthorpe <jgg@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>,
linux-mm@kvack.org, nouveau@lists.freedesktop.org,
bskeggs@redhat.com, akpm@linux-foundation.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, jhubbard@nvidia.com,
rcampbell@nvidia.com, jglisse@redhat.com, hch@infradead.org,
daniel@ffwll.ch, willy@infradead.org, bsingharora@gmail.com,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v8 5/8] mm: Device exclusive memory access
Date: Wed, 19 May 2021 10:28:42 -0300 [thread overview]
Message-ID: <20210519132842.GJ1002214@nvidia.com> (raw)
In-Reply-To: <YKRRgZmRMdk1vH7A@t490s>
On Tue, May 18, 2021 at 07:45:05PM -0400, Peter Xu wrote:
> On Tue, May 18, 2021 at 08:03:27PM -0300, Jason Gunthorpe wrote:
> > Logically during fork all these device exclusive pages should be
> > reverted back to their CPU pages, write protected and the CPU page PTE
> > copied to the fork.
> >
> > We should not copy the device exclusive page PTE to the fork. I think
> > I pointed to this on an earlier rev..
>
> Agreed. Though please see the question I posted in the other thread: now I am
> not very sure whether we'll be able to mark a page as device exclusive if that
> page has mapcount>1.
IMHO it is similar to write protect done by filesystems on shared
mappings - all VMAs with a copy of the CPU page have to get switched
to the device exclusive PTE. This is why the rmap stuff is involved in
the migration helpers
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: rcampbell@nvidia.com, willy@infradead.org,
linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org,
bsingharora@gmail.com, Alistair Popple <apopple@nvidia.com>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
hch@infradead.org, linux-mm@kvack.org, bskeggs@redhat.com,
daniel@ffwll.ch, akpm@linux-foundation.org,
Christoph Hellwig <hch@lst.de>
Subject: Re: [Nouveau] [PATCH v8 5/8] mm: Device exclusive memory access
Date: Wed, 19 May 2021 10:28:42 -0300 [thread overview]
Message-ID: <20210519132842.GJ1002214@nvidia.com> (raw)
In-Reply-To: <YKRRgZmRMdk1vH7A@t490s>
On Tue, May 18, 2021 at 07:45:05PM -0400, Peter Xu wrote:
> On Tue, May 18, 2021 at 08:03:27PM -0300, Jason Gunthorpe wrote:
> > Logically during fork all these device exclusive pages should be
> > reverted back to their CPU pages, write protected and the CPU page PTE
> > copied to the fork.
> >
> > We should not copy the device exclusive page PTE to the fork. I think
> > I pointed to this on an earlier rev..
>
> Agreed. Though please see the question I posted in the other thread: now I am
> not very sure whether we'll be able to mark a page as device exclusive if that
> page has mapcount>1.
IMHO it is similar to write protect done by filesystems on shared
mappings - all VMAs with a copy of the CPU page have to get switched
to the device exclusive PTE. This is why the rmap stuff is involved in
the migration helpers
Jason
_______________________________________________
Nouveau mailing list
Nouveau@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/nouveau
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: rcampbell@nvidia.com, willy@infradead.org,
linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org,
bsingharora@gmail.com, Alistair Popple <apopple@nvidia.com>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
hch@infradead.org, linux-mm@kvack.org, jglisse@redhat.com,
bskeggs@redhat.com, jhubbard@nvidia.com,
akpm@linux-foundation.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v8 5/8] mm: Device exclusive memory access
Date: Wed, 19 May 2021 10:28:42 -0300 [thread overview]
Message-ID: <20210519132842.GJ1002214@nvidia.com> (raw)
In-Reply-To: <YKRRgZmRMdk1vH7A@t490s>
On Tue, May 18, 2021 at 07:45:05PM -0400, Peter Xu wrote:
> On Tue, May 18, 2021 at 08:03:27PM -0300, Jason Gunthorpe wrote:
> > Logically during fork all these device exclusive pages should be
> > reverted back to their CPU pages, write protected and the CPU page PTE
> > copied to the fork.
> >
> > We should not copy the device exclusive page PTE to the fork. I think
> > I pointed to this on an earlier rev..
>
> Agreed. Though please see the question I posted in the other thread: now I am
> not very sure whether we'll be able to mark a page as device exclusive if that
> page has mapcount>1.
IMHO it is similar to write protect done by filesystems on shared
mappings - all VMAs with a copy of the CPU page have to get switched
to the device exclusive PTE. This is why the rmap stuff is involved in
the migration helpers
Jason
next prev parent reply other threads:[~2021-05-19 13:28 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 8:42 [PATCH v8 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 1/8] mm: Remove special swap entry functions Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-05-18 2:17 ` Peter Xu
2021-05-18 2:17 ` Peter Xu
2021-05-18 2:17 ` [Nouveau] " Peter Xu
2021-05-18 11:58 ` Alistair Popple
2021-05-18 11:58 ` Alistair Popple
2021-05-18 11:58 ` [Nouveau] " Alistair Popple
2021-05-18 14:17 ` Peter Xu
2021-05-18 14:17 ` Peter Xu
2021-05-18 14:17 ` [Nouveau] " Peter Xu
2021-04-07 8:42 ` [PATCH v8 2/8] mm/swapops: Rework swap entry manipulation code Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-05-18 20:04 ` Liam Howlett
2021-05-18 20:04 ` Liam Howlett
2021-05-18 20:04 ` [Nouveau] " Liam Howlett
2021-05-19 12:38 ` Alistair Popple
2021-05-19 12:38 ` Alistair Popple
2021-05-19 12:38 ` [Nouveau] " Alistair Popple
2021-05-20 20:24 ` Liam Howlett
2021-05-20 20:24 ` Liam Howlett
2021-05-20 20:24 ` [Nouveau] " Liam Howlett
2021-05-21 2:23 ` Alistair Popple
2021-05-21 2:23 ` Alistair Popple
2021-05-21 2:23 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 4/8] mm/rmap: Split migration into its own function Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 5/8] mm: Device exclusive memory access Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-05-18 2:08 ` Peter Xu
2021-05-18 2:08 ` Peter Xu
2021-05-18 2:08 ` [Nouveau] " Peter Xu
2021-05-18 13:19 ` Alistair Popple
2021-05-18 13:19 ` Alistair Popple
2021-05-18 13:19 ` [Nouveau] " Alistair Popple
2021-05-18 17:27 ` Peter Xu
2021-05-18 17:27 ` Peter Xu
2021-05-18 17:27 ` [Nouveau] " Peter Xu
2021-05-18 17:33 ` Jason Gunthorpe
2021-05-18 17:33 ` Jason Gunthorpe
2021-05-18 17:33 ` [Nouveau] " Jason Gunthorpe
2021-05-18 18:01 ` Peter Xu
2021-05-18 18:01 ` Peter Xu
2021-05-18 18:01 ` [Nouveau] " Peter Xu
2021-05-18 19:45 ` Jason Gunthorpe
2021-05-18 19:45 ` Jason Gunthorpe
2021-05-18 19:45 ` [Nouveau] " Jason Gunthorpe
2021-05-18 20:29 ` Peter Xu
2021-05-18 20:29 ` Peter Xu
2021-05-18 20:29 ` [Nouveau] " Peter Xu
2021-05-18 23:03 ` Jason Gunthorpe
2021-05-18 23:03 ` Jason Gunthorpe
2021-05-18 23:03 ` [Nouveau] " Jason Gunthorpe
2021-05-18 23:45 ` Peter Xu
2021-05-18 23:45 ` Peter Xu
2021-05-18 23:45 ` [Nouveau] " Peter Xu
2021-05-19 11:04 ` Alistair Popple
2021-05-19 11:04 ` Alistair Popple
2021-05-19 11:04 ` [Nouveau] " Alistair Popple
2021-05-19 12:15 ` Peter Xu
2021-05-19 12:15 ` Peter Xu
2021-05-19 12:15 ` [Nouveau] " Peter Xu
2021-05-19 13:11 ` Alistair Popple
2021-05-19 13:11 ` Alistair Popple
2021-05-19 13:11 ` [Nouveau] " Alistair Popple
2021-05-19 14:04 ` Peter Xu
2021-05-19 14:04 ` Peter Xu
2021-05-19 14:04 ` [Nouveau] " Peter Xu
2021-05-19 13:28 ` Jason Gunthorpe [this message]
2021-05-19 13:28 ` Jason Gunthorpe
2021-05-19 13:28 ` [Nouveau] " Jason Gunthorpe
2021-05-19 14:09 ` Peter Xu
2021-05-19 14:09 ` Peter Xu
2021-05-19 14:09 ` [Nouveau] " Peter Xu
2021-05-19 18:11 ` Jason Gunthorpe
2021-05-19 18:11 ` Jason Gunthorpe
2021-05-19 18:11 ` [Nouveau] " Jason Gunthorpe
2021-05-19 11:35 ` Alistair Popple
2021-05-19 11:35 ` Alistair Popple
2021-05-19 11:35 ` [Nouveau] " Alistair Popple
2021-05-19 12:21 ` Peter Xu
2021-05-19 12:21 ` Peter Xu
2021-05-19 12:21 ` [Nouveau] " Peter Xu
2021-05-19 12:46 ` Alistair Popple
2021-05-19 12:46 ` Alistair Popple
2021-05-19 12:46 ` [Nouveau] " Alistair Popple
2021-05-21 6:53 ` Alistair Popple
2021-05-21 6:53 ` Alistair Popple
2021-05-21 6:53 ` [Nouveau] " Alistair Popple
2021-05-18 21:16 ` Peter Xu
2021-05-18 21:16 ` Peter Xu
2021-05-18 21:16 ` [Nouveau] " Peter Xu
2021-05-19 10:49 ` Alistair Popple
2021-05-19 10:49 ` Alistair Popple
2021-05-19 10:49 ` [Nouveau] " Alistair Popple
2021-05-19 12:24 ` Peter Xu
2021-05-19 12:24 ` Peter Xu
2021-05-19 12:24 ` [Nouveau] " Peter Xu
2021-05-19 12:46 ` Alistair Popple
2021-05-19 12:46 ` Alistair Popple
2021-05-19 12:46 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 6/8] mm: Selftests for exclusive device memory Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 7/8] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-04-07 8:42 ` [PATCH v8 8/8] nouveau/svm: Implement atomic SVM access Alistair Popple
2021-04-07 8:42 ` Alistair Popple
2021-04-07 8:42 ` [Nouveau] " Alistair Popple
2021-05-21 4:04 ` Ben Skeggs
2021-05-21 4:04 ` Ben Skeggs
2021-05-21 4:04 ` [Nouveau] " Ben Skeggs
2021-05-21 4:04 ` Ben Skeggs
2021-05-06 7:43 ` [PATCH v8 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-05-06 7:43 ` Alistair Popple
2021-05-06 7:43 ` [Nouveau] " Alistair Popple
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