From: Shahaf Shuler <shahafs@mellanox.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
Alejandro Lucero <alejandro.lucero@netronome.com>
Cc: Yongseok Koh <yskoh@mellanox.com>,
Thomas Monjalon <thomas@monjalon.net>,
Ferruh Yigit <ferruh.yigit@intel.com>,
"nhorman@tuxdriver.com" <nhorman@tuxdriver.com>,
Gaetan Rivet <gaetan.rivet@6wind.com>, dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH 0/6] introduce DMA memory mapping for external memory
Date: Thu, 14 Feb 2019 13:28:58 +0000 [thread overview]
Message-ID: <AM6PR0502MB37974B11ADAC93B6419D957DC3670@AM6PR0502MB3797.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <81f4bbef-8d6a-d845-eb07-966bbccf4849@intel.com>
Thursday, February 14, 2019 12:19 PM, Burakov, Anatoly:
> Subject: Re: [dpdk-dev] [PATCH 0/6] introduce DMA memory mapping for
> external memory
>
> On 13-Feb-19 7:24 PM, Shahaf Shuler wrote:
> > Wednesday, February 13, 2019 1:43 PM, Alejandro Lucero:
> >> Subject: Re: [dpdk-dev] [PATCH 0/6] introduce DMA memory mapping for
> >> external memory
> >>
> >> On Wed, Feb 13, 2019 at 9:11 AM Shahaf Shuler
> <shahafs@mellanox.com>
> >> wrote:
> >>
> >>> This series is in continue to RFC[1].
> >>>
> >>> The DPDK APIs expose 3 different modes to work with memory used for
> >> DMA:
> >>>
> >>> 1. Use the DPDK owned memory (backed by the DPDK provided
> >> hugepages).
> >>> This memory is allocated by the DPDK libraries, included in the DPDK
> >>> memory system (memseg lists) and automatically DMA mapped by the
> >> DPDK
> >>> layers.
> >>>
> >>> 2. Use memory allocated by the user and register to the DPDK memory
> >>> systems. This is also referred as external memory. Upon registration
> >>> of the external memory, the DPDK layers will DMA map it to all
> >>> needed devices.
> >>>
> >>> 3. Use memory allocated by the user and not registered to the DPDK
> >>> memory system. This is for users who wants to have tight control on
> >>> this memory. The user will need to explicitly call DMA map function
> >>> in order to register such memory to the different devices.
> >>>
> >>> The scope of the patch focus on #3 above.
> >>>
> >>>
> >> Why can not we have case 2 covering case 3?
> >
> > Because it is not our choice rather the DPDK application.
> > We could not allow it, and force the application to register their external
> memory to the DPDK memory management system. However IMO it will be
> wrong.
> > The use case exists - some application wants to manage their memory by
> themselves. w/o the extra overhead of rte_malloc, without creating a special
> socket to populate the memory and without redundant API calls to
> rte_extmem_*.
> >
> > Simply allocate chunk of memory, DMA map it to device and that’s it.
>
> Just a small note: while this sounds good on paper, i should point out that at
> least *registering* the memory with DPDK is a necessity. You may see
> rte_extmem_* calls as redundant (and i agree, to an extent), but we don't
> advertise our PMD's capabilities in a way that makes it easy to determine
> whether a particular PMD will or will not work without registering external
> memory within DPDK (i.e. does it use
> rte_virt2memseg() internally, for example).
>
> So, extmem register calls are a necessary evil in such case, and IMO should
> be called out as required for such external memory usage scenario.
If we are going to force all to use the extmem, then there is no need w/ this API. we can have the PMDs to register when the memory is registered.
We can just drop the vfio_dma_map APIs and that's it.
>
> --
> Thanks,
> Anatoly
next prev parent reply other threads:[~2019-02-14 13:29 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-13 9:10 Shahaf Shuler
2019-02-13 9:10 ` [dpdk-dev] [PATCH 1/6] vfio: allow DMA map of memory for the default vfio fd Shahaf Shuler
2019-02-13 9:45 ` Gaëtan Rivet
2019-02-13 11:38 ` Gaëtan Rivet
2019-02-13 15:23 ` Shahaf Shuler
2019-02-13 14:41 ` Burakov, Anatoly
2019-02-13 9:10 ` [dpdk-dev] [PATCH 2/6] vfio: don't fail to DMA map if memory is already mapped Shahaf Shuler
2019-02-13 9:58 ` Gaëtan Rivet
2019-02-13 19:52 ` Shahaf Shuler
2019-02-13 9:10 ` [dpdk-dev] [PATCH 3/6] bus: introduce DMA memory mapping for external memory Shahaf Shuler
2019-02-13 11:17 ` Gaëtan Rivet
2019-02-13 19:07 ` Shahaf Shuler
2019-02-14 14:00 ` Gaëtan Rivet
2019-02-17 6:23 ` Shahaf Shuler
2019-02-13 9:10 ` [dpdk-dev] [PATCH 4/6] net/mlx5: refactor external memory registration Shahaf Shuler
2019-02-13 9:10 ` [dpdk-dev] [PATCH 5/6] net/mlx5: support PCI device DMA map and unmap Shahaf Shuler
2019-02-13 11:35 ` Gaëtan Rivet
2019-02-13 11:44 ` Gaëtan Rivet
2019-02-13 19:11 ` Shahaf Shuler
2019-02-14 10:21 ` Gaëtan Rivet
2019-02-21 9:21 ` Shahaf Shuler
2019-02-13 9:10 ` [dpdk-dev] [PATCH 6/6] doc: deprecate VFIO DMA map APIs Shahaf Shuler
2019-02-13 11:43 ` [dpdk-dev] [PATCH 0/6] introduce DMA memory mapping for external memory Alejandro Lucero
2019-02-13 19:24 ` Shahaf Shuler
2019-02-14 10:19 ` Burakov, Anatoly
2019-02-14 13:28 ` Shahaf Shuler [this message]
2019-02-14 16:19 ` Burakov, Anatoly
2019-02-17 6:18 ` Shahaf Shuler
2019-02-18 12:21 ` Burakov, Anatoly
2019-02-14 12:22 ` Alejandro Lucero
2019-02-14 12:27 ` Alejandro Lucero
2019-02-14 13:41 ` Shahaf Shuler
2019-02-14 16:43 ` Burakov, Anatoly
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 " Shahaf Shuler
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 " Shahaf Shuler
2019-03-10 8:27 ` [dpdk-dev] [PATCH v4 " Shahaf Shuler
2019-03-10 8:27 ` [dpdk-dev] [PATCH v4 1/6] vfio: allow DMA map of memory for the default vfio fd Shahaf Shuler
2019-03-30 0:23 ` Thomas Monjalon
2019-03-30 0:23 ` Thomas Monjalon
2019-03-30 14:29 ` Thomas Monjalon
2019-03-30 14:29 ` Thomas Monjalon
2019-03-10 8:27 ` [dpdk-dev] [PATCH v4 2/6] vfio: don't fail to DMA map if memory is already mapped Shahaf Shuler
2019-03-10 8:28 ` [dpdk-dev] [PATCH v4 3/6] bus: introduce device level DMA memory mapping Shahaf Shuler
2019-03-11 10:19 ` Burakov, Anatoly
2019-03-13 9:56 ` Thomas Monjalon
2019-03-13 11:12 ` Shahaf Shuler
2019-03-13 11:19 ` Thomas Monjalon
2019-03-13 11:47 ` Burakov, Anatoly
2019-03-30 14:36 ` Thomas Monjalon
2019-03-30 14:36 ` Thomas Monjalon
2019-03-10 8:28 ` [dpdk-dev] [PATCH v4 4/6] net/mlx5: refactor external memory registration Shahaf Shuler
2019-03-10 8:28 ` [dpdk-dev] [PATCH v4 5/6] net/mlx5: support PCI device DMA map and unmap Shahaf Shuler
2019-03-10 8:28 ` [dpdk-dev] [PATCH v4 6/6] doc: deprecation notice for VFIO DMA map APIs Shahaf Shuler
2019-03-11 10:20 ` Burakov, Anatoly
2019-03-11 17:35 ` Rami Rosen
2019-10-01 15:20 ` David Marchand
2019-10-02 4:53 ` Shahaf Shuler
2019-10-02 7:51 ` David Marchand
2019-03-11 9:27 ` [dpdk-dev] [PATCH v4 0/6] introduce DMA memory mapping for external memory Gaëtan Rivet
2019-03-30 14:40 ` Thomas Monjalon
2019-03-30 14:40 ` Thomas Monjalon
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 1/6] vfio: allow DMA map of memory for the default vfio fd Shahaf Shuler
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 2/6] vfio: don't fail to DMA map if memory is already mapped Shahaf Shuler
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 3/6] bus: introduce device level DMA memory mapping Shahaf Shuler
2019-03-05 16:35 ` Burakov, Anatoly
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 4/6] net/mlx5: refactor external memory registration Shahaf Shuler
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 5/6] net/mlx5: support PCI device DMA map and unmap Shahaf Shuler
2019-03-05 13:59 ` [dpdk-dev] [PATCH v3 6/6] doc: deprecation notice for VFIO DMA map APIs Shahaf Shuler
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 1/6] vfio: allow DMA map of memory for the default vfio fd Shahaf Shuler
2019-02-28 11:56 ` Burakov, Anatoly
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 2/6] vfio: don't fail to DMA map if memory is already mapped Shahaf Shuler
2019-02-28 11:58 ` Burakov, Anatoly
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 3/6] bus: introduce device level DMA memory mapping Shahaf Shuler
2019-02-28 12:14 ` Burakov, Anatoly
2019-02-28 14:41 ` Burakov, Anatoly
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 4/6] net/mlx5: refactor external memory registration Shahaf Shuler
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 5/6] net/mlx5: support PCI device DMA map and unmap Shahaf Shuler
2019-02-21 14:50 ` [dpdk-dev] [PATCH v2 6/6] doc: deprecate VFIO DMA map APIs Shahaf Shuler
2019-02-21 15:50 ` David Marchand
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