[Crash-utility] [PATCH] arm64 : Update the section_size_bits for latest kernel

[lijiang]

On Thu, Nov 4, 2021 at 4:49 PM <crash-utility-request at redhat.com> wrote:

> Date: Thu, 4 Nov 2021 08:47:57 +0000
> From: HAGIO KAZUHITO(?????)     <k-hagio-ab at nec.com>
> To: "er.ankurbansal at gmail.com" <er.ankurbansal at gmail.com>
> Cc: "Discussion list for crash utility usage,   maintenance and
>         development" <crash-utility at redhat.com>
> Subject: Re: [Crash-utility] [PATCH] arm64 : Update the
>         section_size_bits       for     latest kernel
> Message-ID:
>         <
> TYYPR01MB67775E90F3F2EF285ACF5E86DD8D9 at TYYPR01MB6777.jpnprd01.prod.outlook.com
> >
>
> Content-Type: text/plain; charset="iso-2022-jp"
>
> Hi Ankur,
>
> Thanks for the patch.
>
> -----Original Message-----
> > correct the section_size_bits for kernel version >= 5.12
> > becuase of linux upstream change
> >
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=f0b13ee23241846f6f6cd0d
> > 119a8ac8059416ec4
> > (arm64/sparsemem: reduce SECTION_SIZE_BITS)
> >
> > Change-Id: I31b66fbfe421a02aa9f370ce7a615fbc70efcf2f
> > ---
> >  arm64.c | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/arm64.c b/arm64.c
> > index 3dcbcc6..4a207fc 100644
> > --- a/arm64.c
> > +++ b/arm64.c
> > @@ -1123,9 +1123,15 @@ arm64_get_section_size_bits(void)
> >               free(string);
> >       } else if (kt->ikconfig_flags & IKCONFIG_AVAIL) {
> >               if ((ret = get_kernel_config("CONFIG_MEMORY_HOTPLUG",
> NULL)) == IKCONFIG_Y) {
> > -                     if ((ret =
> get_kernel_config("CONFIG_HOTPLUG_SIZE_BITS", &string)) == IKCONFIG_STR)
> > +                     if (THIS_KERNEL_VERSION >= LINUX(5,12,0)){
> > +                             if((ret =
> get_kernel_config("CONFIG_ARM64_64K_PAGES", NULL)) == IKCONFIG_Y)
> > +                                     machdep->section_size_bits = 29;
> > +                             else
> > +                                     machdep->section_size_bits = 27;
> > +                     }
> > +                     else if ((ret =
> get_kernel_config("CONFIG_HOTPLUG_SIZE_BITS", &string)) ==
> > IKCONFIG_STR)
>
> Considering dumpfiles without vmcoreinfo and IKCONFIG too, it will be
> better
> to switch the default value of section_size_bits.  We can use
> machdep->pagesize
> here, so how about this?
>
> -       machdep->section_size_bits = _SECTION_SIZE_BITS;
> +       if (THIS_KERNEL_VERSION >= LINUX(5,12,0)) {
> +               if (machdep->pagesize == 65536)
> +                       machdep->section_size_bits = 29;
> +               else
> +                       machdep->section_size_bits = 27;
> +       } else
> +               machdep->section_size_bits = _SECTION_SIZE_BITS;
>
>
This change covers more scenarios and looks good to me. Could you please
update this patch? Ankur and Kazu.

Thanks.
Lianbo
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