From: Andrew Morton <akpm@linux-foundation.org>
To: Evangelos Petrongonas <epetron@amazon.de>
Cc: Mike Rapoport <rppt@kernel.org>,
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: Thu, 22 Jan 2026 15:21:12 -0800 [thread overview]
Message-ID: <20260122152112.1a8be8e7bdab72631234cd69@linux-foundation.org> (raw)
In-Reply-To: <20260120175913.34368-1-epetron@amazon.de>
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").
next prev parent reply other threads:[~2026-01-23 4:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 17:59 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 [this message]
2026-01-23 8:53 ` Mike Rapoport
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