Re: [RFC PATCH v4 5/6] drivers/migrate_offload: add DMA batch copy driver (dcbm)

Garg, Shivank
2026-04-03T11:06:56Z

On 3/24/2026 1:40 PM, Huang, Ying wrote:
> Hi, Shivank,
>
> Shivank Garg <shivankg@amd.com> writes:
>
>> Simple DMAEngine based driver that uses memcpy channels to batch-copy
>> folios during page migration. Primarily for testing the copy offload
>> infrastructure.
>>
>> When DMA fails the callback returns an error and the migration path
>> falls back to per-folio CPU copy.
>>
>> Sysfs interface under /sys/kernel/dcbm/:
>> offloading - enable/disable DMA offload
>> nr_dma_chan - max number of DMA channels to use
>> folios_migrated - folios copied via DMA
>> folios_failures - fallback count
>
> How about placing the sysfs interface under /sys/module/dcbm/? We will
> have multiple migrator implementations in the future, so dcbm behaves
> more like a driver, right?
>

Good point, I'll move it to /sys/module/dcbm.

Thanks for the review :)

Thanks,
Shivank