RE: [PATCH] dma-mapping: make map_benchmark compile into module

[Song Bao Hua (Barry Song)]

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@xxxxxx]
> Sent: Wednesday, March 24, 2021 8:13 PM
> To: tiantao (H) <tiantao6@xxxxxxxxxxxxx>
> Cc: akpm@xxxxxxxxxxxxxxxxxxxx; peterz@xxxxxxxxxxxxx; paulmck@xxxxxxxxxx;
> ast@xxxxxxxxxx; tglx@xxxxxxxxxxxxx; rostedt@xxxxxxxxxxx; hch@xxxxxx;
> m.szyprowski@xxxxxxxxxxx; Song Bao Hua (Barry Song)
> <song.bao.hua@xxxxxxxxxxxxx>; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] dma-mapping: make map_benchmark compile into module
> 
> On Wed, Mar 24, 2021 at 10:17:38AM +0800, Tian Tao wrote:
> > under some scenarios, it is necessary to compile map_benchmark
> > into module to test iommu, so this patch changed Kconfig and
> > export_symbol to implement map_benchmark compiled into module.
> >
> > On the other hand, map_benchmark is a driver, which is supposed
> > to be able to run as a module.
> >
> > Signed-off-by: Tian Tao <tiantao6@xxxxxxxxxxxxx>
> 
> Nope, we're not going to export more kthread internals for a test
> module.

The requirement comes from an colleague who is frequently changing
the map-bench code for some customized test purpose. and he doesn't
want to build kernel image and reboot every time. So I moved the
requirement to Tao Tian.

Right now, kthread_bind() is exported, kthread_bind_mask() seems
to be a little bit "internal" as you said, maybe a wrapper like
kthread_bind_node() won't be that "internal", comparing to exposing
the cpumask?
Anyway, we don't find other driver users for this, hardly I can
convince you it is worth.

Thanks
Barry