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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	Jerome Glisse <jglisse@redhat.com>,
	John Hubbard <jhubbard@nvidia.com>,
	Christoph Hellwig <hch@lst.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH v5 1/2] mm/mmu_notifier: make interval notifier updates safe
Date: Thu, 16 Jan 2020 10:13:11 -0400
Message-ID: <20200116141311.GB10759@ziepe.ca> (raw)
In-Reply-To: <c9458a81-da38-928f-d8f3-814e06674bec@nvidia.com>

On Wed, Jan 15, 2020 at 02:04:47PM -0800, Ralph Campbell wrote:

> But I see your point if this sequence is done outside of the invalidate
> callback. In that case, if the driver shrank the interval, an invalidate
> callback for the right hand side could be missed before the insertion of
> the new interval for the right hand side.
> I'll explain this in the comments for nouveau_svmm_do_unmap() and
> dmirror_do_unmap().

Yes, this is why I'm not sure this is a good API for the core to
expose.

Batch manipulations is a resonable thing, but it should be forced to
work under safe conditions, ie while holding the required 'inv_begin'
on the interval tree, and the batching APIs should assert this
requirement.

Jason

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16 19:57 [PATCH v5 0/2] mm/hmm/test: add self tests for HMM Ralph Campbell
2019-12-16 19:57 ` [PATCH v5 1/2] mm/mmu_notifier: make interval notifier updates safe Ralph Campbell
2019-12-17 20:51   ` Jason Gunthorpe
2019-12-17 21:50     ` Ralph Campbell
2020-01-09 19:48   ` Jason Gunthorpe
2020-01-09 22:01     ` Ralph Campbell
2020-01-09 23:25       ` Jason Gunthorpe
2020-01-13 22:44         ` Ralph Campbell
2020-01-14 12:45           ` Jason Gunthorpe
2020-01-15 22:04             ` Ralph Campbell
2020-01-16 14:13               ` Jason Gunthorpe [this message]
2019-12-16 19:57 ` [PATCH v5 2/2] mm/hmm/test: add self tests for HMM Ralph Campbell

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