Re: [RFC PATCH 1/2] ARM: mm: support memory-failure

[Xie Yuanbin <xieyuanbin1@huawei.com>]

> It would be helpful to be more specific about what you
> want to do with this.
> 
> Are you working on a driver that would actually make use of
> the exported interface?

Thanks for your reply.

Yes, In fact, we have developed a hardware component to detect DDR bit
transitions (software does not sense the detection behavior). Once a bit
transition is detected, an interrupt is reported to the CPU.

On the software side, we have developed a driver module ko to register
the interrupt callback to perform soft page offline to the corresponding
physical pages.

In fact, we will export `soft_offline_page` for ko to use (we can ensure
that it is not called in the interrupt context), but I have looked at the
code and found that `memory_failure_queue` and `memory_failure` can also
be used, which are already exported.

> I see only a very small number of
> drivers that call memory_failure(), and none of them are
> usable on Arm.

I think that not all drivers are in the open source kernel code.
As far as I know, there should be similar third-party drivers in other
architectures that use memory-failure functions, like x86 or arm64.
I am not a specialist in drivers, so if I have made any mistakes,
please correct me.

Xie Yuanbin