linux-kernel - Re: [PATCH] hugetlb: increase hugepage reservations when using node-specific "hugepages=" cmdline

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Message-Id: <20260122141900.3eb028abe20f6c31808f9b5d@linux-foundation.org>
Date: Thu, 22 Jan 2026 14:19:00 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: "Li Zhe" <lizhe.67@...edance.com>
Cc: <muchun.song@...ux.dev>, <osalvador@...e.de>, <david@...nel.org>,
 <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] hugetlb: increase hugepage reservations when using
 node-specific "hugepages=" cmdline

On Thu, 22 Jan 2026 11:50:02 +0800 "Li Zhe" <lizhe.67@...edance.com> wrote:

> Commit 3dfd02c90037 ("hugetlb: increase number of reserving hugepages
> via cmdline") raised the number of hugepages that can be reserved
> through the boot-time "hugepages=" parameter for the non-node-specific
> case, but left the node-specific form of the same parameter unchanged.
> 
> This patch extends the same optimization to node-specific reservations.
> When HugeTLB vmemmap optimization (HVO) is enabled and a node cannot
> satisfy the requested hugepages, the code first releases ordinary
> struct-page memory of hugepages obtained from the buddy allocator,
> allowing their struct-page memory to be reclaimed and reused for
> additional hugepage reservations on that node.
> 
> This is particularly beneficial for configurations that require
> identical, large per-node hugepage reservations. On a four-node, 384 GB
> x86 VM, the patch raises the attainable 2 MiB hugepage reservation from
> under 374 GB to more than 379 GB.
> 

Thanks.

I *think* the hugepages= documentation in
Documentation/admin-guide/mm/hugetlbpage.rst is still up to date and
complete, but can you please check it, see if there's somethig we should
do?