From: Alistair Popple <apopple@nvidia.com>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, Alistair Popple <apopple@nvidia.com>,
gerald.schaefer@linux.ibm.com, dan.j.williams@intel.com,
jgg@ziepe.ca, willy@infradead.org, david@redhat.com,
linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de,
zhang.lyra@gmail.com, debug@rivosinc.com, bjorn@kernel.org,
balbirs@nvidia.com, lorenzo.stoakes@oracle.com,
linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
linux-cxl@vger.kernel.org, dri-devel@lists.freedesktop.org,
John@Groves.net, m.szyprowski@samsung.com
Subject: [PATCH v3 06/14] mm/huge_memory: Remove pXd_devmap usage from insert_pXd_pfn()
Date: Thu, 19 Jun 2025 18:57:58 +1000 [thread overview]
Message-ID: <cd8658f9ff10afcfffd8b145a39d98bf1c595ffa.1750323463.git-series.apopple@nvidia.com> (raw)
In-Reply-To: <cover.176965585864cb8d2cf41464b44dcc0471e643a0.1750323463.git-series.apopple@nvidia.com>
Nothing uses PFN_DEV anymore so no need to create devmap pXd's when
mapping a PFN. Instead special mappings will be created which ensures
vm_normal_page_pXd() will not return pages which don't have an
associated page. This could change behaviour slightly on architectures
where pXd_devmap() does not imply pXd_special() as the normal page
checks would have fallen through to checking VM_PFNMAP/MIXEDMAP instead,
which in theory at least could have returned a page.
However vm_normal_page_pXd() should never have been returning pages for
pXd_devmap() entries anyway, so anything relying on that would have been
a bug.
Signed-off-by: Alistair Popple <apopple@nvidia.com>
---
Changes since v1:
- New for v2
---
mm/huge_memory.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b096240..6514e25 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1415,11 +1415,7 @@ static int insert_pmd(struct vm_area_struct *vma, unsigned long addr,
add_mm_counter(mm, mm_counter_file(fop.folio), HPAGE_PMD_NR);
} else {
entry = pmd_mkhuge(pfn_t_pmd(fop.pfn, prot));
-
- if (pfn_t_devmap(fop.pfn))
- entry = pmd_mkdevmap(entry);
- else
- entry = pmd_mkspecial(entry);
+ entry = pmd_mkspecial(entry);
}
if (write) {
entry = pmd_mkyoung(pmd_mkdirty(entry));
@@ -1565,11 +1561,7 @@ static void insert_pud(struct vm_area_struct *vma, unsigned long addr,
add_mm_counter(mm, mm_counter_file(fop.folio), HPAGE_PUD_NR);
} else {
entry = pud_mkhuge(pfn_t_pud(fop.pfn, prot));
-
- if (pfn_t_devmap(fop.pfn))
- entry = pud_mkdevmap(entry);
- else
- entry = pud_mkspecial(entry);
+ entry = pud_mkspecial(entry);
}
if (write) {
entry = pud_mkyoung(pud_mkdirty(entry));
--
git-series 0.9.1
next prev parent reply other threads:[~2025-06-19 9:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-19 8:57 [PATCH v3 00/14] mm: Remove pXX_devmap page table bit and pfn_t type Alistair Popple
2025-06-19 8:57 ` [PATCH v3 01/14] mm: Convert pXd_devmap checks to vma_is_dax Alistair Popple
2025-06-19 8:57 ` [PATCH v3 02/14] mm: Filter zone device pages returned from folio_walk_start() Alistair Popple
2025-06-19 8:57 ` [PATCH v3 03/14] mm: Remove remaining uses of PFN_DEV Alistair Popple
2025-06-19 8:57 ` [PATCH v3 04/14] mm: Convert vmf_insert_mixed() from using pte_devmap to pte_special Alistair Popple
2025-06-19 8:57 ` [PATCH v3 05/14] mm/gup: Remove pXX_devmap usage from get_user_pages() Alistair Popple
2025-06-19 8:57 ` Alistair Popple [this message]
2025-06-19 8:57 ` [PATCH v3 07/14] mm: Remove redundant pXd_devmap calls Alistair Popple
2025-06-19 8:58 ` [PATCH v3 08/14] mm/khugepaged: Remove redundant pmd_devmap() check Alistair Popple
2025-06-19 8:58 ` [PATCH v3 09/14] powerpc: Remove checks for devmap pages and PMDs/PUDs Alistair Popple
2025-06-19 8:58 ` [PATCH v3 10/14] fs/dax: Remove FS_DAX_LIMITED config option Alistair Popple
2025-06-19 8:58 ` [PATCH v3 11/14] mm: Remove devmap related functions and page table bits Alistair Popple
2025-06-19 8:58 ` [PATCH v3 12/14] mm: Remove PFN_DEV, PFN_MAP, PFN_SPECIAL, PFN_SG_CHAIN and PFN_SG_LAST Alistair Popple
2025-06-19 8:58 ` [PATCH v3 13/14] mm: Remove callers of pfn_t functionality Alistair Popple
2025-06-19 8:58 ` [PATCH v3 14/14] mm/memremap: Remove unused devmap_managed_key Alistair Popple
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