[dpdk-dev] [PATCH] bus/fslmc: support for hotplugging of memory

[Burakov, Anatoly]

On 09-Apr-18 8:49 AM, Shreyansh Jain wrote:
> Hello Anatoly,
> 
> On Sunday 08 April 2018 10:44 PM, Burakov, Anatoly wrote:
>> On 05-Apr-18 3:14 PM, Shreyansh Jain wrote:
>>> Restructure VFIO DMA code for handling hotplug memory events
>>> (callbacks) and --legacy case.
>>>
>>> Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
>>> ---
>>>
>>> ###
>>> This is based on the 16fbfef04a3 github repository. This is assuming
>>> that changes already exists as done in patch 26/68.
>>> Though, this can be a standalone, replacing 26/88. Though, the Makefile
>>> changes don't exist in this.
>>> Also, this just a first draft. I will push any review changes after this
>>> incrementally over v4.
>>> ###
>>
>> Hi Shreyansh,
>>
>> I think we can keep the 26/68 as it still works within the context of 
>> the patchset. I would like to add these changes closer to the end, 
>> where we enable support for callbacks in VFIO (this could/should come 
>> as the next patch).
> 
> But then it would also mean that dpaa2 would be broken within the memory 
> hotplug patches?
> I think it would be broken once the memseg ceases to be continuous 
> physical sets.
> 

Hi Shreyansh,

Why would it be broken? Even when memseg change comes into effect, 
legacy mem is not enabled until much later in the patchset, when all of 
the callback/multiprocess business is in place. For all intents and 
purposes, this stays valid for legacy mode, hence not broken.

We later enable callbacks etc. on VFIO, but technically they still 
aren't enabled until 65 (67 in v4), when it becomes possible to actually 
run DPDK in non-legacy mode.

So, for the duration of this patchset, dpaa2 is not broken, as far as i 
can tell. Keeping in mind that only legacy mode will be available until 
patch 65/67, what exactly is being broken here?

-- 
Thanks,
Anatoly