linux-kernel - Re: [PATCH v2] x86/gart/kcore: Exclude GART aperture from kcore

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Date:   Thu, 24 Jan 2019 10:17:44 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Kairui Song <kasong@...hat.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, jbohac@...e.cz,
        adobriyan@...il.com, Andrew Morton <akpm@...ux-foundation.org>,
        osandov@...com, Bhupesh Sharma <bhsharma@...hat.com>,
        Dave Young <dyoung@...hat.com>
Subject: Re: [PATCH v2] x86/gart/kcore: Exclude GART aperture from kcore

On 01/23/19 at 10:50pm, Kairui Song wrote:
> > >  int fix_aperture __initdata = 1;
> > >
> > > -#ifdef CONFIG_PROC_VMCORE
> > > +#if defined(CONFIG_PROC_VMCORE) || defined(CONFIG_PROC_KCORE)
> > >  /*
> > >   * If the first kernel maps the aperture over e820 RAM, the kdump kernel will
> > >   * use the same range because it will remain configured in the northbridge.
> > > @@ -66,7 +67,7 @@ int fix_aperture __initdata = 1;
> > >   */
> > >  static unsigned long aperture_pfn_start, aperture_page_count;
> > >
> > > -static int gart_oldmem_pfn_is_ram(unsigned long pfn)
> > > +static int gart_mem_pfn_is_ram(unsigned long pfn)
> > >  {
> > >       return likely((pfn < aperture_pfn_start) ||
> > >                     (pfn >= aperture_pfn_start + aperture_page_count));
> > > @@ -76,7 +77,12 @@ static void exclude_from_vmcore(u64 aper_base, u32 aper_order)
> >
> > Shouldn't this function name be changed? It's not only handling vmcore
> > stuff any more, but also kcore. And this function is not excluding, but
> > resgistering.
> >
> > Other than this, it looks good to me.
> >
> > Thanks
> > Baoquan
> >
> 
> Good suggestion, it's good to change this function name too to avoid
> any misleading. This patch hasn't got any other reviews recently, I'll
> update it shortly.

There's more.

These two are doing the same thing:
  register_mem_pfn_is_ram
  register_oldmem_pfn_is_ram

Need remove one of them and put it in a right place. Furthermore, may
need see if there's existing function which is used to register a
function to a hook.

Secondly, exclude_from_vmcore() is not excluding anthing, it's only
registering a function which is used to judge if oldmem/pfn is ram. Need
rename it.

Thanks
Baoquan