From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Yishai Hadas <yishaih@nvidia.com>,
linux-rdma@vger.kernel.org
Subject: Re: [PATCH rdma-next v2 1/4] IB/core: Improve ODP to use hmm_range_fault()
Date: Tue, 29 Sep 2020 19:15:21 +0100 [thread overview]
Message-ID: <20200929181521.GA8089@infradead.org> (raw)
In-Reply-To: <20200929181325.GA9475@nvidia.com>
On Tue, Sep 29, 2020 at 03:13:25PM -0300, Jason Gunthorpe wrote:
> My eventual hope is to be able to send this DMA page list to the HW
> without having to parse and copy it like is done today. We already
> have it in a linear array that can be DMA'd from.
>
> However, the HW knows 0 means need-fault (the flag bits are zero), it
> doesn't know what to do with DMA_MAPPING_ERROR..
I think you are falling into the same traps as the original hmm
code. The above might be true for mlx5 hardware, but this is generic
infrastructure. Making any assumptions about being able to directly
pass it on to hardware is just futile. Nevermind such pesky things
as endianess conversions.
next prev parent reply other threads:[~2020-09-29 18:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 8:21 [PATCH rdma-next v2 0/4] Improve ODP by using HMM API Leon Romanovsky
2020-09-22 8:21 ` [PATCH rdma-next v2 1/4] IB/core: Improve ODP to use hmm_range_fault() Leon Romanovsky
2020-09-29 17:59 ` Jason Gunthorpe
2020-09-29 18:02 ` Christoph Hellwig
2020-09-29 18:13 ` Jason Gunthorpe
2020-09-29 18:15 ` Christoph Hellwig [this message]
2020-09-29 18:27 ` Jason Gunthorpe
2020-09-29 20:20 ` Yishai Hadas
2020-09-29 19:27 ` Jason Gunthorpe
2020-09-29 20:09 ` Yishai Hadas
2020-09-29 20:13 ` Jason Gunthorpe
2020-09-29 20:30 ` Yishai Hadas
2020-09-30 0:37 ` Jason Gunthorpe
2020-09-29 21:34 ` Yishai Hadas
2020-09-30 0:35 ` Jason Gunthorpe
2020-09-30 7:32 ` Yishai Hadas
2020-09-22 8:21 ` [PATCH rdma-next v2 2/4] IB/core: Enable ODP sync without faulting Leon Romanovsky
2020-09-22 8:21 ` [PATCH rdma-next v2 3/4] RDMA/mlx5: Extend advice MR to support non faulting mode Leon Romanovsky
2020-09-22 8:21 ` [PATCH rdma-next v2 4/4] RDMA/mlx5: Sync device with CPU pages upon ODP MR registration Leon Romanovsky
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