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Subject: Re: [PATCH v3 19/20] PCI/P2PDMA: introduce pci_mmap_p2pmem()
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Logan Gunthorpe <logang@deltatee.com>,
        Alistair Popple <apopple@nvidia.com>,
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From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
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Date:   Mon, 4 Oct 2021 16:54:03 +0200
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Am 04.10.21 um 15:27 schrieb Jason Gunthorpe:
> On Mon, Oct 04, 2021 at 03:22:22PM +0200, Christian König wrote:
>
>> That use case is completely unrelated to GUP and when this doesn't work we
>> have quite a problem.
> My read is that unmap_mapping_range() guarentees the physical TLB
> hardware is serialized across all CPUs upon return.

Thanks, that's what I wanted to make sure.

Christian.

>
> It also guarentees GUP slow is serialized due to the page table
> spinlocks.
>
> Jason