From: "Oscar Salvador (SUSE)" <osalvador@kernel.org>
To: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>, Qi Zheng <qi.zheng@linux.dev>,
Lance Yang <lance.yang@linux.dev>,
James Houghton <jthoughton@google.com>,
David Hildenbrand <david@kernel.org>,
Muchun Song <muchun.song@linux.dev>,
Yili Zhang <zhangyili01@baidu.com>,
Kiryl Shutsemau <kas@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v4 01/13] mm: hugetlb_vmemmap: fix OOM during head page allocation
Date: Sat, 7 Nov 2026 18:16:22 +0100 [thread overview]
Message-ID: <au9c5jNwv2nhJdzD@localhost.localdomain> (raw)
In-Reply-To: <20261107022756.77731-2-songmuchun@bytedance.com>
On Sat, Nov 07, 2026 at 10:27:44AM +0800, Muchun Song wrote:
> From: Yili Zhang <zhangyili01@baidu.com>
>
> The head page used during HugeTLB vmemmap optimization is allocated with
> a bare GFP_KERNEL mask. When boot-time hugepage allocation drains free
> memory, parallel optimization workers can enter OOM handling before
> userspace exists, leaving the kernel with no killable process and causing
> a panic.
>
> hugetlb_pages_alloc_boot_node() invokes HVO on the folios accumulated so
> far when available memory reaches zero, allowing the released vmemmap pages
> to support further hugepage allocations. If allocating the HVO head page
> returns -ENOMEM, the bulk HVO path frees any vmemmap pages it has already
> accumulated and retries, while callers can continue with an unoptimized
> folio if the retry still fails. Therefore, neither an allocation warning
> nor OOM handling helps this best-effort allocation. Use GFP_KERNEL |
> __GFP_NOWARN | __GFP_RETRY_MAYFAIL to allow reclaim retries while avoiding
> both.
>
> Fixes: c0b495b91a47 ("mm/hugetlb: refactor code around vmemmap_walk")
> Cc: stable@vger.kernel.org
> Signed-off-by: Yili Zhang <zhangyili01@baidu.com>
> Co-developed-by: Muchun Song <songmuchun@bytedance.com>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org>
--
Oscar Salvador
SUSE Labs
next prev parent reply other threads:[~2026-11-07 17:16 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-07 2:27 [PATCH v4 00/13] mm: Decouple folio-based vmemmap optimization from HugeTLB Muchun Song
2026-11-07 2:27 ` [PATCH v4 01/13] mm: hugetlb_vmemmap: fix OOM during head page allocation Muchun Song
2026-11-07 17:16 ` Oscar Salvador (SUSE) [this message]
2026-11-07 2:27 ` [PATCH v4 02/13] mm: hugetlb_vmemmap: remove HugeTLB-specific vmemmap optimization macros Muchun Song
2026-11-07 2:27 ` [PATCH v4 03/13] mm: hugetlb_vmemmap: unify VMEMMAP_{SPLIT,REMAP}_NO_TLB_FLUSH Muchun Song
2026-11-07 2:27 ` [PATCH v4 04/13] mm: hugetlb_vmemmap: simplify vmemmap head page handling Muchun Song
2026-11-07 2:27 ` [PATCH v4 05/13] mm: hugetlb_vmemmap: generalize vmemmap page allocation Muchun Song
2026-11-07 2:27 ` [PATCH v4 06/13] mm: hugetlb_vmemmap: unify writable vmemmap page preparation Muchun Song
2026-11-07 2:27 ` [PATCH v4 07/13] mm: hugetlb_vmemmap: rename vmemmap_remap_pte() to vmemmap_optimize_pte() Muchun Song
2026-11-07 2:27 ` [PATCH v4 08/13] mm: hugetlb_vmemmap: simplify shared tail page handling Muchun Song
2026-11-07 2:27 ` [PATCH v4 09/13] mm: hugetlb_vmemmap: move alloc_vmemmap_page_list() next to its free helper Muchun Song
2026-11-07 2:27 ` [PATCH v4 10/13] mm: hugetlb_vmemmap: make vmemmap optimization folio-oriented Muchun Song
2026-11-07 2:27 ` [PATCH v4 11/13] mm: hugetlb_vmemmap: make vmemmap restoration folio-oriented Muchun Song
2026-11-07 2:27 ` [PATCH v4 12/13] mm: hugetlb_vmemmap: unify vmemmap range restoration Muchun Song
2026-11-07 2:27 ` [PATCH v4 13/13] mm: hugetlb_vmemmap: make vmemmap PTE conversion folio-oriented Muchun Song
2026-11-07 3:53 ` [PATCH v4 00/13] mm: Decouple folio-based vmemmap optimization from HugeTLB Andrew Morton
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