From: Mike Rapoport <rppt@kernel.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: akpm@linux-foundation.org, izumi.taku@jp.fujitsu.com,
linux-mm@kvack.org, Yuan Liu <yuan1.liu@intel.com>,
David Hildenbrand <david@kernel.org>
Subject: Re: [PATCH] mm/mm_init: fix incorrect node_spanned_pages
Date: Tue, 23 Jun 2026 12:22:15 +0300 [thread overview]
Message-ID: <ajpQR0hX681OryCB@kernel.org> (raw)
In-Reply-To: <20260623083507.kg7jmd7ofz3awqmq@master>
Hi Wei,
On Tue, Jun 23, 2026 at 08:35:07AM +0000, Wei Yang wrote:
> On Mon, Jun 22, 2026 at 04:58:47PM +0300, Mike Rapoport wrote:
> >On Mon, Jun 22, 2026 at 02:24:03AM +0000, Wei Yang wrote:
> >> Current node_spanned_pages is got as a summation of all zone's spanned page
> >> in calculate_node_totalpages(). Generally this is good, but if we use
> >> kernelcore=mirror, it is would be wrong.
> >>
> >> As we already passed in node_start_pfn and node_end_pfn, fix this by get it
> >> from (node_start_pfn - node_end_pfn) directly.
> >>
> >> Fixes: 342332e6a925 ("mm/page_alloc.c: introduce kernelcore=mirror option")
> >> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> >> Cc: Yuan Liu <yuan1.liu@intel.com>
> >
> >I queued it for now, will push to one of memblock branches after merge
> >window closes.
> >
>
> After some investigation, I found current mirrored_kernelcore may still affect
> memmap_init() in some aspects.
>
> But how to fix is not sure, will prepare an RFC for discussion.
After I applied your patch, I did some checks to see why
mirrored_kernelcore causes us troubles. I found that unlike other variants
of kernelcore/movablecore settings, mirrored_kernelcore creates zone
overlap for no apparent reason. I did some git archaeology and I didn't
find a justification for making overlapping pages absent in ZONE_NORMAL.
So I came up with this cleanup:
https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=kernelcore-mirror
I'm waiting for the bots to chew on it before positing the patches.
> --
> Wei Yang
> Help you, Help me
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2026-06-23 9:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-22 2:24 [PATCH] mm/mm_init: fix incorrect node_spanned_pages Wei Yang
2026-06-22 13:58 ` Mike Rapoport
2026-06-23 8:35 ` Wei Yang
2026-06-23 9:22 ` Mike Rapoport [this message]
2026-06-23 9:26 ` Wei Yang
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