From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alistair Popple <apopple@nvidia.com>
Cc: 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,
kvm-ppc@vger.kernel.org, dri-devel@lists.freedesktop.org,
jhubbard@nvidia.com, rcampbell@nvidia.com, jglisse@redhat.com
Subject: Re: [PATCH 1/9] mm/migrate.c: Always allow device private pages to migrate
Date: Tue, 09 Feb 2021 13:39:32 +0000 [thread overview]
Message-ID: <20210209133932.GD4718@ziepe.ca> (raw)
In-Reply-To: <20210209010722.13839-2-apopple@nvidia.com>
On Tue, Feb 09, 2021 at 12:07:14PM +1100, Alistair Popple wrote:
> Device private pages are used to represent device memory that is not
> directly accessible from the CPU. Extra references to a device private
> page are only used to ensure the struct page itself remains valid whilst
> waiting for migration entries. Therefore extra references should not
> prevent device private page migration as this can lead to failures to
> migrate pages back to the CPU which are fatal to the user process.
This should identify the extra references in expected_count, just
disabling this protection seems unsafe, ZONE_DEVICE is not so special
that the refcount means nothing
Is this a side effect of the extra refcounts that Ralph was trying to
get rid of? I'd rather see that work finished :)
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alistair Popple <apopple@nvidia.com>
Cc: 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,
kvm-ppc@vger.kernel.org, dri-devel@lists.freedesktop.org,
jhubbard@nvidia.com, rcampbell@nvidia.com, jglisse@redhat.com
Subject: Re: [PATCH 1/9] mm/migrate.c: Always allow device private pages to migrate
Date: Tue, 9 Feb 2021 09:39:32 -0400 [thread overview]
Message-ID: <20210209133932.GD4718@ziepe.ca> (raw)
In-Reply-To: <20210209010722.13839-2-apopple@nvidia.com>
On Tue, Feb 09, 2021 at 12:07:14PM +1100, Alistair Popple wrote:
> Device private pages are used to represent device memory that is not
> directly accessible from the CPU. Extra references to a device private
> page are only used to ensure the struct page itself remains valid whilst
> waiting for migration entries. Therefore extra references should not
> prevent device private page migration as this can lead to failures to
> migrate pages back to the CPU which are fatal to the user process.
This should identify the extra references in expected_count, just
disabling this protection seems unsafe, ZONE_DEVICE is not so special
that the refcount means nothing
Is this a side effect of the extra refcounts that Ralph was trying to
get rid of? I'd rather see that work finished :)
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alistair Popple <apopple@nvidia.com>
Cc: rcampbell@nvidia.com, linux-doc@vger.kernel.org,
nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org,
linux-mm@kvack.org, bskeggs@redhat.com,
akpm@linux-foundation.org
Subject: Re: [Nouveau] [PATCH 1/9] mm/migrate.c: Always allow device private pages to migrate
Date: Tue, 9 Feb 2021 09:39:32 -0400 [thread overview]
Message-ID: <20210209133932.GD4718@ziepe.ca> (raw)
In-Reply-To: <20210209010722.13839-2-apopple@nvidia.com>
On Tue, Feb 09, 2021 at 12:07:14PM +1100, Alistair Popple wrote:
> Device private pages are used to represent device memory that is not
> directly accessible from the CPU. Extra references to a device private
> page are only used to ensure the struct page itself remains valid whilst
> waiting for migration entries. Therefore extra references should not
> prevent device private page migration as this can lead to failures to
> migrate pages back to the CPU which are fatal to the user process.
This should identify the extra references in expected_count, just
disabling this protection seems unsafe, ZONE_DEVICE is not so special
that the refcount means nothing
Is this a side effect of the extra refcounts that Ralph was trying to
get rid of? I'd rather see that work finished :)
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@ziepe.ca>
To: Alistair Popple <apopple@nvidia.com>
Cc: rcampbell@nvidia.com, linux-doc@vger.kernel.org,
nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org,
linux-mm@kvack.org, jglisse@redhat.com, bskeggs@redhat.com,
jhubbard@nvidia.com, akpm@linux-foundation.org
Subject: Re: [PATCH 1/9] mm/migrate.c: Always allow device private pages to migrate
Date: Tue, 9 Feb 2021 09:39:32 -0400 [thread overview]
Message-ID: <20210209133932.GD4718@ziepe.ca> (raw)
In-Reply-To: <20210209010722.13839-2-apopple@nvidia.com>
On Tue, Feb 09, 2021 at 12:07:14PM +1100, Alistair Popple wrote:
> Device private pages are used to represent device memory that is not
> directly accessible from the CPU. Extra references to a device private
> page are only used to ensure the struct page itself remains valid whilst
> waiting for migration entries. Therefore extra references should not
> prevent device private page migration as this can lead to failures to
> migrate pages back to the CPU which are fatal to the user process.
This should identify the extra references in expected_count, just
disabling this protection seems unsafe, ZONE_DEVICE is not so special
that the refcount means nothing
Is this a side effect of the extra refcounts that Ralph was trying to
get rid of? I'd rather see that work finished :)
Jason
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2021-02-09 13:39 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 1:07 [PATCH 0/9] Add support for SVM atomics in Nouveau Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 1/9] mm/migrate.c: Always allow device private pages to migrate Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 13:39 ` Jason Gunthorpe [this message]
2021-02-09 13:39 ` Jason Gunthorpe
2021-02-09 13:39 ` [Nouveau] " Jason Gunthorpe
2021-02-09 13:39 ` Jason Gunthorpe
2021-02-10 3:40 ` Alistair Popple
2021-02-10 3:40 ` Alistair Popple
2021-02-10 3:40 ` [Nouveau] " Alistair Popple
2021-02-10 3:40 ` Alistair Popple
2021-02-10 12:56 ` Jason Gunthorpe
2021-02-10 12:56 ` Jason Gunthorpe
2021-02-10 12:56 ` [Nouveau] " Jason Gunthorpe
2021-02-10 12:56 ` Jason Gunthorpe
2021-02-09 1:07 ` [PATCH 2/9] mm/migrate.c: Allow pfn flags to be passed to migrate_vma_setup() Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 3/9] mm/migrate: Add a unmap and pin migration mode Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 4/9] Documentation: Add unmap and pin to HMM Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 5/9] hmm-tests: Add test for unmap and pin Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 6/9] nouveau/dmem: Only map migrating pages Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 7/9] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 8/9] nouveau/dmem: Add support for multiple page types Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [PATCH 9/9] nouveau/svm: Implement atomic SVM access Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 1:07 ` [Nouveau] " Alistair Popple
2021-02-09 1:07 ` Alistair Popple
2021-02-09 10:27 ` [PATCH 0/9] Add support for SVM atomics in Nouveau Daniel Vetter
2021-02-09 10:27 ` Daniel Vetter
2021-02-09 10:27 ` [Nouveau] " Daniel Vetter
2021-02-09 10:27 ` Daniel Vetter
2021-02-09 12:57 ` Alistair Popple
2021-02-09 12:57 ` Alistair Popple
2021-02-09 12:57 ` [Nouveau] " Alistair Popple
2021-02-09 12:57 ` Alistair Popple
2021-02-09 13:35 ` Jason Gunthorpe
2021-02-09 13:35 ` Jason Gunthorpe
2021-02-09 13:35 ` [Nouveau] " Jason Gunthorpe
2021-02-09 13:35 ` Jason Gunthorpe
2021-02-09 13:39 ` Daniel Vetter
2021-02-09 13:39 ` Daniel Vetter
2021-02-09 13:39 ` [Nouveau] " Daniel Vetter
2021-02-09 13:39 ` Daniel Vetter
2021-02-09 13:44 ` Jason Gunthorpe
2021-02-09 13:44 ` Jason Gunthorpe
2021-02-09 13:44 ` [Nouveau] " Jason Gunthorpe
2021-02-09 13:44 ` Jason Gunthorpe
2021-02-09 21:17 ` Jerome Glisse
2021-02-09 21:17 ` Jerome Glisse
2021-02-09 21:17 ` [Nouveau] " Jerome Glisse
2021-02-09 21:17 ` Jerome Glisse
2021-02-10 17:56 ` Jason Gunthorpe
2021-02-10 17:56 ` Jason Gunthorpe
2021-02-10 17:56 ` [Nouveau] " Jason Gunthorpe
2021-02-10 17:56 ` Jason Gunthorpe
2021-02-09 13:37 ` Daniel Vetter
2021-02-09 13:37 ` Daniel Vetter
2021-02-09 13:37 ` [Nouveau] " Daniel Vetter
2021-02-09 13:37 ` Daniel Vetter
2021-02-09 20:53 ` John Hubbard
2021-02-09 20:53 ` John Hubbard
2021-02-09 20:53 ` [Nouveau] " John Hubbard
2021-02-09 20:53 ` John Hubbard
2021-02-10 12:59 ` Daniel Vetter
2021-02-10 12:59 ` Daniel Vetter
2021-02-10 12:59 ` [Nouveau] " Daniel Vetter
2021-02-10 12:59 ` Daniel Vetter
2021-02-11 2:26 ` John Hubbard
2021-02-11 2:26 ` John Hubbard
2021-02-11 2:26 ` [Nouveau] " John Hubbard
2021-02-11 2:26 ` John Hubbard
2021-02-10 17:59 ` Jason Gunthorpe
2021-02-10 17:59 ` Jason Gunthorpe
2021-02-10 17:59 ` [Nouveau] " Jason Gunthorpe
2021-02-10 17:59 ` Jason Gunthorpe
2021-02-11 7:55 ` Christoph Hellwig
2021-02-11 7:55 ` [Nouveau] " Christoph Hellwig
2021-02-17 23:00 ` Alistair Popple
2021-02-17 23:00 ` Alistair Popple
2021-02-17 23:00 ` [Nouveau] " Alistair Popple
2021-02-17 23:00 ` Alistair Popple
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