From: Andrew Morton <akpm@linux-foundation.org>
To: Baoquan He <bhe@redhat.com>
Cc: Pingfan Liu <kernelfans@gmail.com>,
Bhupesh Sharma <bhupesh.sharma@linaro.org>,
Kazuhito Hagio <k-hagio@ab.jp.nec.com>,
Dave Young <dyoung@redhat.com>, Boris Petkov <bp@alien8.de>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
James Morse <james.morse@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Dave Anderson <anderson@redhat.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
kexec@lists.infradead.org, x86@kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] crash_core, vmcoreinfo: Append 'SECTION_SIZE_BITS' to vmcoreinfo
Date: Tue, 8 Jun 2021 14:14:10 -0700 [thread overview]
Message-ID: <20210608141410.0026a925ba3a609b0dd4e560@linux-foundation.org> (raw)
In-Reply-To: <20210608142432.GA587883@MiWiFi-R3L-srv>
On Tue, 8 Jun 2021 22:24:32 +0800 Baoquan He <bhe@redhat.com> wrote:
> On 06/08/21 at 06:33am, Pingfan Liu wrote:
> > As mentioned in kernel commit 1d50e5d0c505 ("crash_core, vmcoreinfo:
> > Append 'MAX_PHYSMEM_BITS' to vmcoreinfo"), SECTION_SIZE_BITS in the
> > formula:
> > #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
> >
> > Besides SECTIONS_SHIFT, SECTION_SIZE_BITS is also used to calculate
> > PAGES_PER_SECTION in makedumpfile just like kernel.
> >
> > Unfortunately, this arch-dependent macro SECTION_SIZE_BITS changes, e.g.
> > recently in kernel commit f0b13ee23241 ("arm64/sparsemem: reduce
> > SECTION_SIZE_BITS"). But user space wants a stable interface to get this
> > info. Such info is impossible to be deduced from a crashdump vmcore.
> > Hence append SECTION_SIZE_BITS to vmcoreinfo.
>
> ...
>
> Add the discussion of the original thread in kexec ML for reference:
> http://lists.infradead.org/pipermail/kexec/2021-June/022676.html
I added a Link: for this.
> This looks good to me.
>
> Acked-by: Baoquan He <bhe@redhat.com>
I'm thinking we should backport this at least to Fixes:f0b13ee23241.
But perhaps it's simpler to just backport it as far as possible, so I
added a bare cc:stable with no Fixes:. Thoughts?
next prev parent reply other threads:[~2021-06-08 21:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-08 10:33 [PATCH] crash_core, vmcoreinfo: Append 'SECTION_SIZE_BITS' to vmcoreinfo Pingfan Liu
2021-06-08 14:24 ` Baoquan He
2021-06-08 21:14 ` Andrew Morton [this message]
2021-06-09 2:47 ` Baoquan He
2021-06-09 0:16 ` Pingfan Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210608141410.0026a925ba3a609b0dd4e560@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=anderson@redhat.com \
--cc=benh@kernel.crashing.org \
--cc=bhe@redhat.com \
--cc=bhupesh.sharma@linaro.org \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dyoung@redhat.com \
--cc=james.morse@arm.com \
--cc=k-hagio@ab.jp.nec.com \
--cc=kernelfans@gmail.com \
--cc=kexec@lists.infradead.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mark.rutland@arm.com \
--cc=mingo@kernel.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).