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: Wed, 16 Oct 2024 12:45:55 -0300 [thread overview]
Message-ID: <20241016154555.GE4020792@ziepe.ca> (raw)
In-Reply-To: <87frow8wdk.fsf@nvdebian.thelocal>
On Wed, Oct 16, 2024 at 04:10:53PM +1100, Alistair Popple wrote:
> On that note how is the refcounting of the returned p2pdma page expected
> to work? We don't want the driver calling hmm_range_fault() to be able
> to pin the page with eg. get_page(), so the returned p2pdma page should
> have a zero refcount to enforce that.
I think that is just the rule for hmm stuff in general, don't touch
the refcount.
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.
Jason
next prev parent reply other threads:[~2024-10-16 15:46 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 [this message]
2024-10-17 1:58 ` Alistair Popple
2024-10-17 11:53 ` Jason Gunthorpe
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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