Re: [PATCH v2] mm/hotplug, x86: Disable ARCH_MEMORY_PROBE by default

From: Toshi Kani
Date: Thu Jul 25 2013 - 18:37:05 EST


On Thu, 2013-07-25 at 23:38 +0200, Ingo Molnar wrote:
> * Toshi Kani <toshi.kani@xxxxxx> wrote:
>
> > > You claimed that the only purpose of this on x86 was
> > > that testing was done on non-hotplug systems, using
> > > this interface. Non-hotplug systems have e820 maps.
> >
> > Right. Sorry, I first thought that the interface needed
> > to work as defined, i.e. detect a new memory. But for
> > the test purpose on non-hotplug systems, that is not
> > necessary. So, I agree that we can check e820.
> >
> > I summarized two options in the email below.
> > https://lkml.org/lkml/2013/7/23/602
> >
> > Option 1) adds a check with e820. Option 2) deprecates
> > the interface by removing the config option from x86
> > Kconfig. I was thinking that we could evaluate two
> > options after this patch gets in. Does it make sense?
>
> Yeah.
>
> That having said, if the e820 check is too difficult to
> pull off straight away, I also don't mind keeping it as-is
> if it's useful for testing. Just make sure you document it
> as "you need to be careful with this" (beyond it being a
> root-only interface to begin with).

Sounds good. I will keep it as-is for now, and add more clarification
to the document. I will send an updated patch shortly.

I will make sure to come back after this patch gets in and we get more
info about users.

Thanks,
-Toshi

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