From: Shivank Garg <shivankg@amd.com>
To: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>, Rik van Riel <riel@surriel.com>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>, Harry Yoo <harry@kernel.org>,
Jann Horn <jannh@google.com>, Lance Yang <lance.yang@linux.dev>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Zi Yan <ziy@nvidia.com>,
Matthew Brost <matthew.brost@intel.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Gregory Price <gourry@gourry.net>,
Ying Huang <ying.huang@linux.alibaba.com>,
"Alistair Popple" <apopple@nvidia.com>
Cc: Karim Manaouil <kmanaouil.dev@gmail.com>,
Frank van der Linden <fvdl@google.com>,
Kinsey Ho <kinseyho@google.com>, Wei Xu <weixugc@google.com>,
Bharata B Rao <bharata@amd.com>,
David Rientjes <rientjes@google.com>, Dev Jain <dev.jain@arm.com>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Shivank Garg <shivankg@amd.com>
Subject: [PATCH v2 5/7] mm/rmap: factor out migration PTE construction
Date: Thu, 13 Aug 2026 04:23:16 +0000 [thread overview]
Message-ID: <20260813-migrate-rmap-batch-v2-5-3c5424c555c7@amd.com> (raw)
In-Reply-To: <20260813-migrate-rmap-batch-v2-0-3c5424c555c7@amd.com>
try_to_migrate_one() constructs the migration PTE that replaces a
present PTE or non-present swap PTE.
Factor it into make_migration_pte() which can be shared when the
hugetlb migration path is separated.
No functional change intended.
Signed-off-by: Shivank Garg <shivankg@amd.com>
---
mm/rmap.c | 65 +++++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 38 insertions(+), 27 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 0a4a0945dc65..8b89e32ae489 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2507,6 +2507,42 @@ void try_to_unmap(struct folio *folio, enum ttu_flags flags)
rmap_walk(folio, &rwc);
}
+/* Build the migration PTE that replaces pteval for a page. */
+static pte_t make_migration_pte(struct page *page, pte_t pteval,
+ bool writable, bool anon_exclusive)
+{
+ swp_entry_t entry;
+ pte_t swp_pte;
+
+ if (writable)
+ entry = make_writable_migration_entry(page_to_pfn(page));
+ else if (anon_exclusive)
+ entry = make_readable_exclusive_migration_entry(
+ page_to_pfn(page));
+ else
+ entry = make_readable_migration_entry(page_to_pfn(page));
+
+ if (likely(pte_present(pteval))) {
+ if (pte_young(pteval))
+ entry = make_migration_entry_young(entry);
+ if (pte_dirty(pteval))
+ entry = make_migration_entry_dirty(entry);
+ swp_pte = swp_entry_to_pte(entry);
+ if (pte_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_uffd(pteval))
+ swp_pte = pte_swp_mkuffd(swp_pte);
+ } else {
+ swp_pte = swp_entry_to_pte(entry);
+ if (pte_swp_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_swp_uffd(pteval))
+ swp_pte = pte_swp_mkuffd(swp_pte);
+ }
+
+ return swp_pte;
+}
+
/*
* @arg: enum ttu_flags will be passed to this argument.
*
@@ -2737,7 +2773,6 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
*/
dec_mm_counter(mm, mm_counter(folio));
} else {
- swp_entry_t entry;
pte_t swp_pte;
/*
@@ -2779,32 +2814,8 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
* pte. do_swap_page() will wait until the migration
* pte is removed and then restart fault handling.
*/
- if (writable)
- entry = make_writable_migration_entry(
- page_to_pfn(subpage));
- else if (anon_exclusive)
- entry = make_readable_exclusive_migration_entry(
- page_to_pfn(subpage));
- else
- entry = make_readable_migration_entry(
- page_to_pfn(subpage));
- if (likely(pte_present(pteval))) {
- if (pte_young(pteval))
- entry = make_migration_entry_young(entry);
- if (pte_dirty(pteval))
- entry = make_migration_entry_dirty(entry);
- swp_pte = swp_entry_to_pte(entry);
- if (pte_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_uffd(pteval))
- swp_pte = pte_swp_mkuffd(swp_pte);
- } else {
- swp_pte = swp_entry_to_pte(entry);
- if (pte_swp_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_swp_uffd(pteval))
- swp_pte = pte_swp_mkuffd(swp_pte);
- }
+ swp_pte = make_migration_pte(subpage, pteval,
+ writable, anon_exclusive);
if (folio_test_hugetlb(folio))
set_huge_pte_at(mm, address, pvmw.pte, swp_pte,
hsz);
--
2.43.0
next prev parent reply other threads:[~2026-08-13 4:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-13 4:23 [PATCH v2 0/7] mm: batch rmap walks during large folio migration Shivank Garg
2026-08-13 4:23 ` [PATCH v2 1/7] mm: factor out generic PTE batch detection from swap_pte_batch() Shivank Garg
2026-08-13 9:57 ` David Hildenbrand (Arm)
2026-08-14 8:00 ` Garg, Shivank
2026-08-16 7:48 ` Garg, Shivank
2026-08-13 4:23 ` [PATCH v2 2/7] mm/migrate: factor out migration PTE construction Shivank Garg
2026-08-13 4:23 ` [PATCH v2 3/7] mm/migrate: split remove_migration_pte_hugetlb() out of remove_migration_pte() Shivank Garg
2026-08-13 4:23 ` [PATCH v2 4/7] mm/migrate: batch the restore-side migration rmap walk Shivank Garg
2026-08-13 4:23 ` Shivank Garg [this message]
2026-08-13 4:23 ` [PATCH v2 6/7] mm/rmap: split try_to_migrate_hugetlb_one() out of try_to_migrate_one() Shivank Garg
2026-08-13 4:23 ` [PATCH v2 7/7] mm/rmap: batch the unmap of large folios in try_to_migrate_one() Shivank Garg
2026-08-17 9:14 ` Lance Yang
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