Re: [PATCH] [5/8] Fix logic error in 64bit memory hotadd

Andi Kleen
2008-02-11T13:44:38Z

On Monday 11 February 2008 14:33:33 Ingo Molnar wrote:
>
> * Andi Kleen <ak@suse.de> wrote:
>
> > > Also, your fix, while it solves a real bug we want to fix, is not quite
> > > right for upstream integration yet. I can see 3 immediate problems with
> > > it:
> > >
> > > > + if (!pud_present(*pud)) {
> > > > + pud = (pud_t *)get_zeroed_page(GFP_ATOMIC);
> > >
> > > the GFP_ATOMIC here can fail.
> >
> > The memory hotplug code already uses GFP_ATOMIC elsewhere
> > (spp_getpage)
>
> wrong. The _x86_ memory hotplug code uses GFP_ATOMIC elsewhere.
> The generic memory hotplug code does not.

To be honest I'm a little tired now how you attempt to misinterpret every
word I write. Was it not clear from the context which code
was meant?

>
> and the x86 memory hotplug code uses GFP_ATOMIC and panic() elsewhere
> because:

I see it's all my fault.

>
> > The existing code already panics elsewhere (spp_getpage); i just
> > copied that.
>
> and you had nothing to do with that "existing code"? git-log reveals
> that the GFP_ATOMIC and panic()-ing patch was added 2 years ago and was
> signed off by you:

Should I point out all unclean and buggy code you ever signed
off? @) Just alone in .25-rc1 there is enough of that.

>
> commit 44df75e629106efcada087cead6c3f33ed6bcc60
> Author: Matt Tolentino <metolent@cs.vt.edu>
> Date: Tue Jan 17 07:03:41 2006 +0100
>
> [PATCH] x86_64: add x86-64 support for memory hot-add
>
> [...]
> Signed-off-by: Andi Kleen <ak@suse.de>
>
> We (like most upstream kernel subsystems) generally do not accept
> patches into arch/x86 that spreads a buggy implementation detail
> further. Please submit a patch that cleans up the mess. Thanks,

Ok I withdraw the patch under these circumstances. I'm not your coding
slave and I don't feel strongly enough about the hotplug case to
put much more work into this.

-Andi