[dpdk-dev] [PATCH v1 3/9] mempool: remove callback to get capabilities
Burakov, Anatoly
anatoly.burakov at intel.com
Wed Mar 14 15:40:24 CET 2018
On 10-Mar-18 3:39 PM, Andrew Rybchenko wrote:
> The callback was introduced to let generic code to know octeontx
> mempool driver requirements to use single physically contiguous
> memory chunk to store all objects and align object address to
> total object size. Now these requirements are met using a new
> callbacks to calculate required memory chunk size and to populate
> objects using provided memory chunk.
>
> These capability flags are not used anywhere else.
>
> Restricting capabilities to flags is not generic and likely to
> be insufficient to describe mempool driver features. If required
> in the future, API which returns structured information may be
> added.
>
> Signed-off-by: Andrew Rybchenko <arybchenko at solarflare.com>
> ---
Just a general comment - it is not enough to describe minimum memchunk
requirements. With memory hotplug patchset that's hopefully getting
merged in 18.05, memzones will no longer be guaranteed to be
IOVA-contiguous. So, if a driver requires its mempool to not only be
populated from a single memzone, but a single *physically contiguous*
memzone, going by only callbacks will not do, because whether or not
something should be a single memzone says nothing about whether this
memzone has to also be IOVA-contiguous.
So i believe this needs to stay in one form or another.
(also it would be nice to have a flag that a user could pass to
mempool_create that would force memzone reservation be IOVA-contiguous,
but that's a topic for another conversation. prime user for this would
be KNI.)
--
Thanks,
Anatoly
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