From: Muchun Song <songmuchun@bytedance•com>
To: Andrew Morton <akpm@linux-foundation•org>,
David Hildenbrand <david@kernel•org>,
Catalin Marinas <catalin.marinas@arm•com>,
Will Deacon <will@kernel•org>,
Palmer Dabbelt <palmer@dabbelt•com>,
Paul Walmsley <pjw@kernel•org>,
Huacai Chen <chenhuacai@kernel•org>,
Andreas Larsson <andreas@gaisler•com>,
"David S. Miller" <davem@davemloft•net>
Cc: Muchun Song <muchun.song@linux•dev>,
Muchun Song <songmuchun@bytedance•com>,
linux-mm@kvack•org, linux-kernel@vger•kernel.org,
linux-arm-kernel@lists•infradead.org,
linux-riscv@lists•infradead.org, loongarch@lists•linux.dev,
sparclinux@vger•kernel.org, Alexandre Ghiti <alex@ghiti•fr>,
Albert Ou <aou@eecs•berkeley.edu>,
WANG Xuerui <kernel@xen0n•name>, Lorenzo Stoakes <ljs@kernel•org>,
"Liam R. Howlett" <liam@infradead•org>,
Vlastimil Babka <vbabka@kernel•org>,
Mike Rapoport <rppt@kernel•org>,
Suren Baghdasaryan <surenb@google•com>,
Michal Hocko <mhocko@suse•com>
Subject: [PATCH v3 1/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
Date: Mon, 1 Jun 2026 16:48:40 +0800 [thread overview]
Message-ID: <20260601084845.3792171-2-songmuchun@bytedance.com> (raw)
In-Reply-To: <20260601084845.3792171-1-songmuchun@bytedance.com>
The two weak functions are currently no-ops on every architecture,
forcing each platform that needs them to duplicate the same handful
of lines. Provide a generic implementation:
- vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection.
- vmemmap_check_pmd() verifies that the PMD is present and leaf,
then calls the existing vmemmap_verify() helper.
Architectures that need special handling can continue to override the
weak symbols; everyone else gets the standard version for free.
Signed-off-by: Muchun Song <songmuchun@bytedance•com>
---
v2->v3:
- Replace BUG_ON() with WARN_ON_ONCE() in vmemmap_set_pmd()
---
mm/sparse-vmemmap.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 112ccf9c71ca..99e2be39671b 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -386,12 +386,17 @@ int __meminit vmemmap_populate_hvo(unsigned long addr, unsigned long end,
void __weak __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
unsigned long addr, unsigned long next)
{
+ WARN_ON_ONCE(!pmd_set_huge(pmd, virt_to_phys(p), PAGE_KERNEL));
}
int __weak __meminit vmemmap_check_pmd(pmd_t *pmd, int node,
unsigned long addr, unsigned long next)
{
- return 0;
+ if (!pmd_leaf(pmdp_get(pmd)))
+ return 0;
+ vmemmap_verify((pte_t *)pmd, node, addr, next);
+
+ return 1;
}
int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end,
--
2.54.0
next prev parent reply other threads:[~2026-06-01 8:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-01 8:48 [PATCH v3 0/5] mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and vmemmap_check_pmd() Muchun Song
2026-06-01 8:48 ` Muchun Song [this message]
2026-06-01 12:22 ` [PATCH v3 1/5] mm/sparse-vmemmap: provide " David Hildenbrand (Arm)
2026-06-01 12:37 ` Muchun Song
2026-06-02 4:40 ` Oscar Salvador (SUSE)
2026-06-02 4:41 ` Oscar Salvador (SUSE)
2026-06-01 8:48 ` [PATCH v3 2/5] arm64/mm: drop vmemmap_pmd helpers and use generic code Muchun Song
2026-06-01 12:23 ` David Hildenbrand (Arm)
2026-06-02 4:42 ` Oscar Salvador (SUSE)
2026-06-01 8:48 ` [PATCH v3 3/5] riscv/mm: " Muchun Song
2026-06-01 12:23 ` David Hildenbrand (Arm)
2026-06-02 4:44 ` Oscar Salvador (SUSE)
2026-06-01 8:48 ` [PATCH v3 4/5] loongarch/mm: drop vmemmap_check_pmd helper " Muchun Song
2026-06-01 12:24 ` David Hildenbrand (Arm)
2026-06-01 12:26 ` Muchun Song
2026-06-02 4:45 ` Oscar Salvador (SUSE)
2026-06-01 8:48 ` [PATCH v3 5/5] sparc/mm: " Muchun Song
2026-06-01 12:25 ` David Hildenbrand (Arm)
2026-06-02 4:46 ` Oscar Salvador (SUSE)
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