From: Mike Rapoport <rppt@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Evangelos Petrongonas <epetron@amazon.de>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Pratyush Yadav <pratyush@kernel.org>,
Alexander Graf <graf@amazon.com>, Jason Miu <jasonmiu@google.com>,
linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
linux-mm@kvack.org, nh-open-source@amazon.com
Subject: Re: [PATCH v2] kho: skip memoryless NUMA nodes when reserving scratch areas
Date: Fri, 23 Jan 2026 10:53:42 +0200 [thread overview]
Message-ID: <aXM3FoK7g12P5h91@kernel.org> (raw)
In-Reply-To: <20260122152112.1a8be8e7bdab72631234cd69@linux-foundation.org>
On Thu, Jan 22, 2026 at 03:21:12PM -0800, Andrew Morton wrote:
> On Tue, 20 Jan 2026 17:59:11 +0000 Evangelos Petrongonas <epetron@amazon.de> wrote:
>
> > kho_reserve_scratch() iterates over all online NUMA nodes to allocate
> > per-node scratch memory. On systems with memoryless NUMA nodes (nodes
> > that have CPUs but no memory), memblock_alloc_range_nid() fails because
> > there is no memory available on that node. This causes KHO initialization
> > to fail and kho_enable to be set to false.
> >
> > Some ARM64 systems have NUMA topologies where certain nodes contain only
> > CPUs without any associated memory. These configurations are valid and
> > should not prevent KHO from functioning.
> >
> > Fix this by only counting nodes that have memory (N_MEMORY state) and
> > skip memoryless nodes in the per-node scratch allocation loop.
> >
>
> So kho is unusable on such machines.
>
> Should we backport this? I'm thinking
>
> Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers").
It's only for v6.18, but sure, why not.
--
Sincerely yours,
Mike.
prev parent reply other threads:[~2026-01-23 8:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 17:59 [PATCH v2] kho: skip memoryless NUMA nodes when reserving scratch areas Evangelos Petrongonas
2026-01-20 18:37 ` Pratyush Yadav
2026-01-20 19:00 ` Mike Rapoport
2026-01-22 18:18 ` Pasha Tatashin
2026-01-22 23:21 ` Andrew Morton
2026-01-23 8:53 ` Mike Rapoport [this message]
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=aXM3FoK7g12P5h91@kernel.org \
--to=rppt@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=epetron@amazon.de \
--cc=graf@amazon.com \
--cc=jasonmiu@google.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=nh-open-source@amazon.com \
--cc=pasha.tatashin@soleen.com \
--cc=pratyush@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.