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From: Christoph Hellwig <hch@lst.de>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Christoph Hellwig" <hch@lst.de>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Bharata B Rao" <bharata@linux.ibm.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Ben Skeggs" <bskeggs@redhat.com>,
	"Jerome Glisse" <jglisse@redhat.com>,
	kvm-ppc@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
	linux-mm@kvack.org
Subject: Re: [PATCH 3/4] mm: simplify device private page handling in hmm_range_fault
Date: Tue, 17 Mar 2020 08:34:54 +0100	[thread overview]
Message-ID: <20200317073454.GA5843@lst.de> (raw)
In-Reply-To: <7256f88d-809e-4aba-3c46-a223bd8cc521@nvidia.com>

On Mon, Mar 16, 2020 at 03:49:51PM -0700, Ralph Campbell wrote:
> On 3/16/20 12:32 PM, Christoph Hellwig wrote:
>> Remove the code to fault device private pages back into system memory
>> that has never been used by any driver.  Also replace the usage of the
>> HMM_PFN_DEVICE_PRIVATE flag in the pfns array with a simple
>> is_device_private_page check in nouveau.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Getting rid of HMM_PFN_DEVICE_PRIVATE seems reasonable to me since a driver can
> look at the struct page but what if a driver needs to fault in a page from
> another device's private memory? Should it call handle_mm_fault()?

Obviously no driver cared for that so far.  Once we have test cases
for that and thus testable code we can add code to fault it in from
hmm_vma_handle_pte.


WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: amd-gfx@lists.freedesktop.org, linux-mm@kvack.org,
	nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	kvm-ppc@vger.kernel.org, "Christoph Hellwig" <hch@lst.de>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Jerome Glisse" <jglisse@redhat.com>,
	"Ben Skeggs" <bskeggs@redhat.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Bharata B Rao" <bharata@linux.ibm.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH 3/4] mm: simplify device private page handling in hmm_range_fault
Date: Tue, 17 Mar 2020 08:34:54 +0100	[thread overview]
Message-ID: <20200317073454.GA5843@lst.de> (raw)
In-Reply-To: <7256f88d-809e-4aba-3c46-a223bd8cc521@nvidia.com>

On Mon, Mar 16, 2020 at 03:49:51PM -0700, Ralph Campbell wrote:
> On 3/16/20 12:32 PM, Christoph Hellwig wrote:
>> Remove the code to fault device private pages back into system memory
>> that has never been used by any driver.  Also replace the usage of the
>> HMM_PFN_DEVICE_PRIVATE flag in the pfns array with a simple
>> is_device_private_page check in nouveau.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Getting rid of HMM_PFN_DEVICE_PRIVATE seems reasonable to me since a driver can
> look at the struct page but what if a driver needs to fault in a page from
> another device's private memory? Should it call handle_mm_fault()?

Obviously no driver cared for that so far.  Once we have test cases
for that and thus testable code we can add code to fault it in from
hmm_vma_handle_pte.
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Christoph Hellwig" <hch@lst.de>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Bharata B Rao" <bharata@linux.ibm.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Ben Skeggs" <bskeggs@redhat.com>,
	"Jerome Glisse" <jglisse@redhat.com>,
	kvm-ppc@vger.kernel.org, amd-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
	linux-mm@kvack.org
Subject: Re: [PATCH 3/4] mm: simplify device private page handling in hmm_range_fault
Date: Tue, 17 Mar 2020 07:34:54 +0000	[thread overview]
Message-ID: <20200317073454.GA5843@lst.de> (raw)
In-Reply-To: <7256f88d-809e-4aba-3c46-a223bd8cc521@nvidia.com>

On Mon, Mar 16, 2020 at 03:49:51PM -0700, Ralph Campbell wrote:
> On 3/16/20 12:32 PM, Christoph Hellwig wrote:
>> Remove the code to fault device private pages back into system memory
>> that has never been used by any driver.  Also replace the usage of the
>> HMM_PFN_DEVICE_PRIVATE flag in the pfns array with a simple
>> is_device_private_page check in nouveau.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Getting rid of HMM_PFN_DEVICE_PRIVATE seems reasonable to me since a driver can
> look at the struct page but what if a driver needs to fault in a page from
> another device's private memory? Should it call handle_mm_fault()?

Obviously no driver cared for that so far.  Once we have test cases
for that and thus testable code we can add code to fault it in from
hmm_vma_handle_pte.

  reply	other threads:[~2020-03-17  7:34 UTC|newest]

Thread overview: 196+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-16 19:32 ensure device private pages have an owner v2 Christoph Hellwig
2020-03-16 19:32 ` Christoph Hellwig
2020-03-16 19:32 ` Christoph Hellwig
2020-03-16 19:32 ` [PATCH 1/4] memremap: add an owner field to struct dev_pagemap Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 20:55   ` Ralph Campbell
2020-03-16 20:55     ` Ralph Campbell
2020-03-16 20:55     ` Ralph Campbell
2020-03-16 20:55     ` Ralph Campbell
2020-03-16 20:55     ` Ralph Campbell
2020-03-16 19:32 ` [PATCH 2/4] mm: handle multiple owners of device private pages in migrate_vma Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 21:43   ` Ralph Campbell
2020-03-16 21:43     ` Ralph Campbell
2020-03-16 21:43     ` Ralph Campbell
2020-03-16 21:43     ` Ralph Campbell
2020-03-16 21:43     ` Ralph Campbell
2020-03-16 19:32 ` [PATCH 3/4] mm: simplify device private page handling in hmm_range_fault Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:59   ` Jason Gunthorpe
2020-03-16 19:59     ` Jason Gunthorpe
2020-03-16 19:59     ` Jason Gunthorpe
2020-03-16 19:59     ` Jason Gunthorpe
2020-03-16 21:33     ` Christoph Hellwig
2020-03-16 21:33       ` Christoph Hellwig
2020-03-16 21:33       ` Christoph Hellwig
2020-03-16 22:49   ` Ralph Campbell
2020-03-16 22:49     ` Ralph Campbell
2020-03-16 22:49     ` Ralph Campbell
2020-03-16 22:49     ` Ralph Campbell
2020-03-16 22:49     ` Ralph Campbell
2020-03-17  7:34     ` Christoph Hellwig [this message]
2020-03-17  7:34       ` Christoph Hellwig
2020-03-17  7:34       ` Christoph Hellwig
2020-03-17 22:43       ` Ralph Campbell
2020-03-17 22:43         ` Ralph Campbell
2020-03-17 22:43         ` Ralph Campbell
2020-03-17 22:43         ` Ralph Campbell
2020-03-18  9:34         ` Christoph Hellwig
2020-03-18  9:34           ` Christoph Hellwig
2020-03-18  9:34           ` Christoph Hellwig
2020-03-17 12:15     ` Jason Gunthorpe
2020-03-17 12:15       ` Jason Gunthorpe
2020-03-17 12:15       ` Jason Gunthorpe
2020-03-17 12:15       ` Jason Gunthorpe
2020-03-17 12:24       ` Christoph Hellwig
2020-03-17 12:24         ` Christoph Hellwig
2020-03-17 12:24         ` Christoph Hellwig
2020-03-17 12:28         ` Christoph Hellwig
2020-03-17 12:28           ` Christoph Hellwig
2020-03-17 12:28           ` Christoph Hellwig
2020-03-17 12:47           ` Jason Gunthorpe
2020-03-17 12:47             ` Jason Gunthorpe
2020-03-17 12:47             ` Jason Gunthorpe
2020-03-17 12:47             ` Jason Gunthorpe
2020-03-17 12:59             ` Christoph Hellwig
2020-03-17 12:59               ` Christoph Hellwig
2020-03-17 12:59               ` Christoph Hellwig
2020-03-17 17:32               ` Jason Gunthorpe
2020-03-17 17:32                 ` Jason Gunthorpe
2020-03-17 17:32                 ` Jason Gunthorpe
2020-03-17 17:32                 ` Jason Gunthorpe
2020-03-17 17:32                 ` Jason Gunthorpe
2020-03-17 23:14               ` Ralph Campbell
2020-03-17 23:14                 ` Ralph Campbell
2020-03-17 23:14                 ` Ralph Campbell
2020-03-17 23:14                 ` Ralph Campbell
2020-03-19 18:17                 ` Jason Gunthorpe
2020-03-19 18:17                   ` Jason Gunthorpe
2020-03-19 18:17                   ` Jason Gunthorpe
2020-03-19 18:17                   ` Jason Gunthorpe
2020-03-19 22:56                   ` Ralph Campbell
2020-03-19 22:56                     ` Ralph Campbell
2020-03-19 22:56                     ` Ralph Campbell
2020-03-19 22:56                     ` Ralph Campbell
2020-03-20  0:03                     ` Jason Gunthorpe
2020-03-20  0:03                       ` Jason Gunthorpe
2020-03-20  0:03                       ` Jason Gunthorpe
2020-03-20  0:03                       ` Jason Gunthorpe
2020-03-21  8:20                       ` Christoph Hellwig
2020-03-21  8:20                         ` Christoph Hellwig
2020-03-21  8:20                         ` Christoph Hellwig
2020-03-20  0:14                 ` Jason Gunthorpe
2020-03-20  0:14                   ` Jason Gunthorpe
2020-03-20  0:14                   ` Jason Gunthorpe
2020-03-20  0:14                   ` Jason Gunthorpe
2020-03-20  1:33                   ` Ralph Campbell
2020-03-20  1:33                     ` Ralph Campbell
2020-03-20  1:33                     ` Ralph Campbell
2020-03-20  1:33                     ` Ralph Campbell
2020-03-20 12:58                     ` Jason Gunthorpe
2020-03-20 12:58                       ` Jason Gunthorpe
2020-03-20 12:58                       ` Jason Gunthorpe
2020-03-20 12:58                       ` Jason Gunthorpe
2020-03-20 12:58                       ` Jason Gunthorpe
2020-03-16 19:32 ` [PATCH 4/4] mm: check the device private page owner " Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:32   ` Christoph Hellwig
2020-03-16 19:49   ` Jason Gunthorpe
2020-03-16 19:49     ` Jason Gunthorpe
2020-03-16 19:49     ` Jason Gunthorpe
2020-03-16 19:49     ` Jason Gunthorpe
2020-03-16 23:11   ` Ralph Campbell
2020-03-16 23:11     ` Ralph Campbell
2020-03-16 23:11     ` Ralph Campbell
2020-03-16 23:11     ` Ralph Campbell
2020-03-16 23:11     ` Ralph Campbell
2020-03-20 13:41   ` Jason Gunthorpe
2020-03-20 13:41     ` Jason Gunthorpe
2020-03-20 13:41     ` Jason Gunthorpe
2020-03-20 13:41     ` Jason Gunthorpe
2020-03-21  8:22     ` Christoph Hellwig
2020-03-21  8:22       ` Christoph Hellwig
2020-03-21  8:22       ` Christoph Hellwig
2020-03-21 12:38       ` Jason Gunthorpe
2020-03-21 12:38         ` Jason Gunthorpe
2020-03-21 12:38         ` Jason Gunthorpe
2020-03-21 12:38         ` Jason Gunthorpe
2020-03-21 15:18         ` Christoph Hellwig
2020-03-21 15:18           ` Christoph Hellwig
2020-03-21 15:18           ` Christoph Hellwig
2020-03-17  5:31 ` ensure device private pages have an owner v2 Bharata B Rao
2020-03-17  5:43   ` Bharata B Rao
2020-03-17  5:31   ` Bharata B Rao
2020-03-19  0:28 ` Jason Gunthorpe
2020-03-19  0:28   ` Jason Gunthorpe
2020-03-19  0:28   ` Jason Gunthorpe
2020-03-19  0:28   ` Jason Gunthorpe
2020-03-19  7:16   ` Christoph Hellwig
2020-03-19  7:16     ` Christoph Hellwig
2020-03-19  7:16     ` Christoph Hellwig
2020-03-19 11:50     ` Jason Gunthorpe
2020-03-19 11:50       ` Jason Gunthorpe
2020-03-19 11:50       ` Jason Gunthorpe
2020-03-19 11:50       ` Jason Gunthorpe
2020-03-19 18:50     ` Jason Gunthorpe
2020-03-19 18:50       ` Jason Gunthorpe
2020-03-19 18:50       ` Jason Gunthorpe
2020-03-19 18:50       ` Jason Gunthorpe
  -- strict thread matches above, loose matches on Subject: below --
2020-03-16 17:52 ensure device private pages have an owner Christoph Hellwig
2020-03-16 17:52 ` Christoph Hellwig
2020-03-16 17:52 ` Christoph Hellwig
2020-03-16 17:52 ` [PATCH 1/2] mm: handle multiple owners of device private pages in migrate_vma Christoph Hellwig
2020-03-16 17:52   ` Christoph Hellwig
2020-03-16 17:52   ` Christoph Hellwig
2020-03-16 18:17   ` Jason Gunthorpe
2020-03-16 18:17     ` Jason Gunthorpe
2020-03-16 18:17     ` Jason Gunthorpe
2020-03-16 18:17     ` Jason Gunthorpe
2020-03-16 18:20     ` Christoph Hellwig
2020-03-16 18:20       ` Christoph Hellwig
2020-03-16 18:20       ` Christoph Hellwig
2020-03-16 17:52 ` [PATCH 2/2] mm: remove device private page support from hmm_range_fault Christoph Hellwig
2020-03-16 17:52   ` Christoph Hellwig
2020-03-16 17:52   ` Christoph Hellwig
2020-03-16 18:42   ` Ralph Campbell
2020-03-16 18:42     ` Ralph Campbell
2020-03-16 18:42     ` Ralph Campbell
2020-03-16 18:42     ` Ralph Campbell
2020-03-16 18:42     ` Ralph Campbell
2020-03-16 18:49     ` Christoph Hellwig
2020-03-16 18:49       ` Christoph Hellwig
2020-03-16 18:49       ` Christoph Hellwig
2020-03-16 18:58       ` Christoph Hellwig
2020-03-16 18:58         ` Christoph Hellwig
2020-03-16 18:58         ` Christoph Hellwig
2020-03-16 19:56       ` Ralph Campbell
2020-03-16 19:56         ` Ralph Campbell
2020-03-16 19:56         ` Ralph Campbell
2020-03-16 19:56         ` Ralph Campbell
2020-03-16 20:09       ` Jason Gunthorpe
2020-03-16 20:09         ` Jason Gunthorpe
2020-03-16 20:09         ` Jason Gunthorpe
2020-03-16 20:09         ` Jason Gunthorpe
2020-03-16 20:24         ` Ralph Campbell
2020-03-16 20:24           ` Ralph Campbell
2020-03-16 20:24           ` Ralph Campbell
2020-03-16 20:24           ` Ralph Campbell
2020-03-17 11:56           ` Jason Gunthorpe
2020-03-17 11:56             ` Jason Gunthorpe
2020-03-17 11:56             ` Jason Gunthorpe
2020-03-17 11:56             ` Jason Gunthorpe
2020-03-17 22:46             ` Ralph Campbell
2020-03-17 22:46               ` Ralph Campbell
2020-03-17 22:46               ` Ralph Campbell
2020-03-17 22:46               ` Ralph Campbell
2020-03-16 19:04     ` Jason Gunthorpe
2020-03-16 19:04       ` Jason Gunthorpe
2020-03-16 19:04       ` Jason Gunthorpe
2020-03-16 19:04       ` Jason Gunthorpe
2020-03-16 19:07       ` Christoph Hellwig
2020-03-16 19:07         ` Christoph Hellwig
2020-03-16 19:07         ` Christoph Hellwig

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