From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Dave Young <ruirui.yang@linux.dev>
Cc: David Carlier <devnexen@gmail.com>,
akpm@linux-foundation.org, axelrasmussen@google.com,
baohua@kernel.org, baolin.wang@linux.alibaba.com,
baoquan.he@linux.dev, brendan.jackman@linux.dev, dakr@kernel.org,
driver-core@lists.linux.dev, gregkh@linuxfoundation.org,
hannes@cmpxchg.org, jan.kiszka@siemens.com, kasong@tencent.com,
kbingham@kernel.org, liam@infradead.org,
linux-cxl@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org,
mhocko@suse.com, osalvador@suse.de, qi.zheng@linux.dev,
rafael@kernel.org, rppt@kernel.org, shakeel.butt@linux.dev,
surenb@google.com, vbabka@kernel.org, weixugc@google.com,
yuanchu@google.com, ziy@nvidia.com,
devel@lists.crash-utility.osci.io, kexec@lists.infradead.org,
Baoquan He <baoquan.he@linux.dev>
Subject: Re: [PATCH v2 10/13] mm/sparse: remove SECTION_MARKED_PRESENT
Date: Mon, 28 Sep 2026 10:50:11 +0200 [thread overview]
Message-ID: <9009312f-0ffb-4425-ab82-1eb7e52a4646@kernel.org> (raw)
In-Reply-To: <aroezLexo1WoeYI7@darkstar>
On 9/28/26 10:01, Dave Young wrote:
> Cced kexec list.
>
> On Mon, Sep 28, 2026 at 09:28:08AM +0200, David Hildenbrand (Arm) wrote:
>> On 9/27/26 21:20, David Carlier wrote:
>>>
>>> Hi David,
>>
>> Hi!
>>
>>>
>>> It seems dropping SECTION_MARKED_PRESENT_BIT shifts the other section flags down
>>> one bit. crash hardcodes SECTION_HAS_MEM_MAP as (1UL << 1) in
>>> pfn_to_map(), so it now tests SECTION_IS_ONLINE: offline and
>>> ZONE_DEVICE sections no longer resolve to a struct page. makedumpfile
>>> only checks bit 0 and is fine.
>>
>> Thanks. To be expected when relying on kernel internals.
>>
>> Which makes me wonder why makedumpfile
>> (https://github.com/makedumpfile/makedumpfile) not require any such information.
>>
>>>
>>> Keep bit 0 reserved, or export the bits via vmcoreinfo?
>> We could export it, or crash can simply detect the change based on the kernel
>> version. I remember the latter was done in makedumpfile in the past (although we
>> export it).
>>
>> I can send a separate patch to export it.
>
> Thanks David. Checking kernel internals via kernel version is not a good idea
> due to the downstream kernels.
Patch at:
https://lore.kernel.org/r/20260928-section_has_mem_map-v1-1-4129f6ba2838@kernel.org
--
Cheers,
David
next prev parent reply other threads:[~2026-09-28 8:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-21 19:58 [PATCH v2 00/13] mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 01/13] mm/sparse: move mem_section init to sparse_extreme_init() David Hildenbrand (Arm)
2026-09-21 23:12 ` Zi Yan
2026-09-21 19:58 ` [PATCH v2 02/13] mm/sparse: refactor sparse_sections_init() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 03/13] mm/sparse: move initialization of section metadata to sparse_metadata_init() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 04/13] mm/sparse: rename and cleanup sparse_init_nid() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 05/13] mm/sparse: cleanup sparse_init_one_section() David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 06/13] mm/sparse: rename __highest_present_section_nr to __highest_used_section_nr David Hildenbrand (Arm)
2026-09-21 19:58 ` [PATCH v2 07/13] mm/sparse: remove pfn_in_present_section() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 08/13] mm/sparse: move __highest_used_section_nr handling David Hildenbrand (Arm)
2026-09-22 4:24 ` Oscar Salvador (SUSE)
2026-09-22 10:22 ` David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 09/13] scripts/gdb: mm.py: remove fallbacks for SECTION_HAS_MEM_MAP and SECTION_IS_EARLY David Hildenbrand (Arm)
2026-09-22 6:49 ` Seongjun Hong
2026-09-21 19:59 ` [PATCH v2 10/13] mm/sparse: remove SECTION_MARKED_PRESENT David Hildenbrand (Arm)
2026-09-27 19:20 ` David Carlier
2026-09-28 7:28 ` David Hildenbrand (Arm)
2026-09-28 8:01 ` Dave Young
2026-09-28 8:50 ` David Hildenbrand (Arm) [this message]
2026-09-28 8:31 ` Baoquan He
2026-09-21 19:59 ` [PATCH v2 11/13] mm/sparse: remove flags parameter from sparse_init_one_section() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 12/13] fs/proc/page: clarify comment in get_max_dump_pfn() David Hildenbrand (Arm)
2026-09-21 19:59 ` [PATCH v2 13/13] mm/memory_hotplug: drop CONFIG_HAVE_ARCH_PFN_VALID handling from pfn_to_online_page() David Hildenbrand (Arm)
2026-09-22 4:25 ` Oscar Salvador (SUSE)
2026-09-21 22:53 ` [PATCH v2 00/13] mm/sparse: remove SECTION_MARKED_PRESENT and further cleanups Andrew Morton
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=9009312f-0ffb-4425-ab82-1eb7e52a4646@kernel.org \
--to=david@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=axelrasmussen@google.com \
--cc=baohua@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=baoquan.he@linux.dev \
--cc=brendan.jackman@linux.dev \
--cc=dakr@kernel.org \
--cc=devel@lists.crash-utility.osci.io \
--cc=devnexen@gmail.com \
--cc=driver-core@lists.linux.dev \
--cc=gregkh@linuxfoundation.org \
--cc=hannes@cmpxchg.org \
--cc=jan.kiszka@siemens.com \
--cc=kasong@tencent.com \
--cc=kbingham@kernel.org \
--cc=kexec@lists.infradead.org \
--cc=liam@infradead.org \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=mhocko@suse.com \
--cc=osalvador@suse.de \
--cc=qi.zheng@linux.dev \
--cc=rafael@kernel.org \
--cc=rppt@kernel.org \
--cc=ruirui.yang@linux.dev \
--cc=shakeel.butt@linux.dev \
--cc=surenb@google.com \
--cc=vbabka@kernel.org \
--cc=weixugc@google.com \
--cc=yuanchu@google.com \
--cc=ziy@nvidia.com \
/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
all inboxes | Powered by JetHome®