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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alistair Popple <apopple@nvidia.com>
Cc: Yonatan Maman <ymaman@nvidia.com>,
	nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-rdma@vger.kernel.org, linux-mm@kvack.org,
	herbst@redhat.com, lyude@redhat.com, dakr@redhat.com,
	airlied@gmail.com, simona@ffwll.ch, leon@kernel.org,
	jglisse@redhat.com, akpm@linux-foundation.org,
	dri-devel@lists.freedesktop.org, bskeggs@nvidia.com,
	Gal Shalom <GalShalom@nvidia.com>
Subject: Re: [PATCH v1 1/4] mm/hmm: HMM API for P2P DMA to device zone pages
Date: Thu, 17 Oct 2024 08:53:04 -0300	[thread overview]
Message-ID: <20241017115304.GH4020792@ziepe.ca> (raw)
In-Reply-To: <878quno4os.fsf@nvdebian.thelocal>

On Thu, Oct 17, 2024 at 12:58:48PM +1100, Alistair Popple wrote:

> Actually I think the rule should be don't look at the page at
> all. hmm_range_fault() is about mirroring PTEs, no assumption should
> even be made about the existence or otherwise of a struct page.

We are not there yet..
 
> > We don't need to enforce, it we don't know what else the driver will
> > want to use that P2P page for after all. It might stick it in a VMA
> > for some unrelated reason.
> 
> And wouldn't that touch the refcount and therefore be wrong?

I mean the originating driver would do that

Jason


  reply	other threads:[~2024-10-17 11:53 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-15 15:23 [PATCH v1 0/4] GPU Direct RDMA (P2P DMA) for Device Private Pages Yonatan Maman
2024-10-15 15:23 ` [PATCH v1 1/4] mm/hmm: HMM API for P2P DMA to device zone pages Yonatan Maman
2024-10-16  4:49   ` Christoph Hellwig
2024-10-16 15:04     ` Yonatan Maman
2024-10-16 15:44     ` Jason Gunthorpe
2024-10-16 16:41       ` Christoph Hellwig
2024-10-16 17:44         ` Jason Gunthorpe
2024-10-17 11:58           ` Christoph Hellwig
2024-10-17 13:05             ` Jason Gunthorpe
2024-10-17 13:12               ` Christoph Hellwig
2024-10-17 13:46                 ` Jason Gunthorpe
2024-10-17 13:49                   ` Christoph Hellwig
2024-10-17 14:05                     ` Jason Gunthorpe
2024-10-17 14:19                       ` Christoph Hellwig
2024-10-16  5:10   ` Alistair Popple
2024-10-16 15:45     ` Jason Gunthorpe
2024-10-17  1:58       ` Alistair Popple
2024-10-17 11:53         ` Jason Gunthorpe [this message]
2024-10-15 15:23 ` [PATCH v1 2/4] nouveau/dmem: HMM P2P DMA for private dev pages Yonatan Maman
2024-10-16  5:12   ` Alistair Popple
2024-10-16 15:18     ` Yonatan Maman
2024-10-15 15:23 ` [PATCH v1 3/4] IB/core: P2P DMA for device private pages Yonatan Maman
2024-10-15 15:23 ` [PATCH v1 4/4] RDMA/mlx5: Enabling ATS for ODP memory Yonatan Maman
2024-10-16  4:23 ` [PATCH v1 0/4] GPU Direct RDMA (P2P DMA) for Device Private Pages Christoph Hellwig
2024-10-16 15:16   ` Yonatan Maman
2024-10-16 22:22     ` Alistair Popple
2024-10-18  7:26     ` Zhu Yanjun
2024-10-20 15:26       ` Yonatan Maman

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