Re: x86: memtest bootparam

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 18 Apr 2008 15:07:46 -0700
"Yinghai Lu" <yhlu.kernel@gmail.com> wrote:

> On Fri, Apr 18, 2008 at 2:52 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
> > On Fri, 18 Apr 2008 17:17:44 GMT
> >  Linux Kernel Mailing List <linux-kernel@vger.kernel.org> wrote:
> >
> >  > Gitweb:     http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c64df70793a9c344874eb4af19f85e0662d2d3ee
> >  > Commit:     c64df70793a9c344874eb4af19f85e0662d2d3ee
> >  > Parent:     9b967106da0357ef8b08847dce35584a04134f20
> >  > Author:     Yinghai Lu <yhlu.kernel.send@gmail.com>
> >  > AuthorDate: Fri Mar 21 18:56:19 2008 -0700
> >  > Committer:  Ingo Molnar <mingo@elte.hu>
> >  > CommitDate: Thu Apr 17 17:41:21 2008 +0200
> >  >
> >  >     x86: memtest bootparam
> >  >
> >  > ...
> >  >
> >  >
> >  > +     memtest=        [KNL,X86_64] Enable memtest
> >  > +                     Format: <integer>
> >  > +                     range: 0,4 : pattern number
> >  > +                     default : 0 <disable>
> >
> >  OK.  Did the new memtest feature get documented anywhere, btw?  I'm only
> >  vaguely aware of its existence.
> 
> need one text file in Documentation ?

Well if there was a single CONFIG_MEMTEST then it would probably be
sufficent to document it all within the Kconfig help for that option.

But there isn't a CONFIG_MEMTEST.  It appears that the presence or absence
of the memtest feature is controlled by CONFIG_MEMTEST_BOOTPARAM which
makes no sense at all!

> >  These seem pointless.  Why not just unconditionally implement memtest=?
> >  All the code for that should be __init anyway so we're hardly saving
> >  anything here.
> 
> also
> for big box, like 64g above, that will take a while.

So... such users shouldn't add the memtest= boot parameter?


I'd suggest the following:

- Add a CONFIG_MEMTEST.  No other config variable needed.

- Put all the memtest code inside #ifdef CONFIG_MEMTEST.

- As part of that memtest code, implement the memtest= boot option

- Make the memtest feature default to "off" if memtest= was not provided.


That's all very simple and conventional?