From: Dev Jain <dev.jain@arm.com>
To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org,
chrisl@kernel.org, kasong@tencent.com, hughd@google.com,
liam@infradead.org
Cc: Dev Jain <dev.jain@arm.com>,
riel@surriel.com, vbabka@kernel.org, harry@kernel.org,
jannh@google.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, qi.zheng@linux.dev, shakeel.butt@linux.dev,
baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com,
weixugc@google.com, shikemeng@huaweicloud.com, nphamcs@gmail.com,
bhe@redhat.com, youngjun.park@lge.com,
baolin.wang@linux.alibaba.com, pfalcato@suse.de,
ryan.roberts@arm.com, anshuman.khandual@arm.com
Subject: [PATCH v4 10/12] mm/rmap: refactor anon folio unmap in try_to_unmap_one
Date: Tue, 26 May 2026 12:06:33 +0530 [thread overview]
Message-ID: <20260526063635.61721-11-dev.jain@arm.com> (raw)
In-Reply-To: <20260526063635.61721-1-dev.jain@arm.com>
Refactor anonymous folio unmap to ttu_anon_folio.
No functional change intended.
Signed-off-by: Dev Jain <dev.jain@arm.com>
---
mm/rmap.c | 116 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 68 insertions(+), 48 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index c0e385882f562..b1639bad8e27f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2136,6 +2136,70 @@ static inline bool ttu_lazyfree_folio(struct vm_area_struct *vma,
return true;
}
+static inline void set_swp_pte_at(struct mm_struct *mm, unsigned long address,
+ pte_t *ptep, swp_entry_t entry, pte_t pteval, bool anon_exclusive)
+{
+ pte_t swp_pte = swp_entry_to_pte(entry);
+
+ if (anon_exclusive)
+ swp_pte = pte_swp_mkexclusive(swp_pte);
+
+ if (likely(pte_present(pteval))) {
+ if (pte_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_uffd_wp(pteval))
+ swp_pte = pte_swp_mkuffd_wp(swp_pte);
+ } else {
+ /* Device-exclusive entry */
+ if (pte_swp_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
+ if (pte_swp_uffd_wp(pteval))
+ swp_pte = pte_swp_mkuffd_wp(swp_pte);
+ }
+
+ set_pte_at(mm, address, ptep, swp_pte);
+}
+
+static inline bool ttu_anon_folio(struct vm_area_struct *vma, struct folio *folio,
+ struct page *subpage, unsigned long address, pte_t *ptep,
+ pte_t pteval)
+{
+ bool anon_exclusive = folio_test_anon(folio) && PageAnonExclusive(subpage);
+ swp_entry_t entry = page_swap_entry(subpage);
+ struct mm_struct *mm = vma->vm_mm;
+
+ if (folio_dup_swap_pages(folio, subpage, 1) < 0)
+ return false;
+
+ /*
+ * arch_unmap_one() is expected to be a NOP on
+ * architectures where we could have PFN swap PTEs,
+ * so we'll not check/care.
+ */
+ if (arch_unmap_one(mm, vma, address, pteval) < 0) {
+ folio_put_swap_pages(folio, subpage, 1);
+ return false;
+ }
+
+ /* See folio_try_share_anon_rmap(): clear PTE first. */
+ if (anon_exclusive && folio_try_share_anon_rmap_pte(folio, subpage)) {
+ folio_put_swap_pages(folio, subpage, 1);
+ return false;
+ }
+
+ if (list_empty(&mm->mmlist)) {
+ spin_lock(&mmlist_lock);
+ if (list_empty(&mm->mmlist))
+ list_add(&mm->mmlist, &init_mm.mmlist);
+ spin_unlock(&mmlist_lock);
+ }
+
+ dec_mm_counter(mm, MM_ANONPAGES);
+ inc_mm_counter(mm, MM_SWAPENTS);
+ set_swp_pte_at(mm, address, ptep, entry, pteval, anon_exclusive);
+ return true;
+}
+
/*
* @arg: enum ttu_flags will be passed to this argument
*/
@@ -2144,7 +2208,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
{
struct mm_struct *mm = vma->vm_mm;
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0);
- bool anon_exclusive, ret = true;
+ bool ret = true;
pte_t pteval;
struct page *subpage;
struct mmu_notifier_range range;
@@ -2252,8 +2316,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
subpage = folio_page(folio, pfn - folio_pfn(folio));
address = pvmw.address;
- anon_exclusive = folio_test_anon(folio) &&
- PageAnonExclusive(subpage);
if (likely(pte_present(pteval))) {
nr_pages = folio_unmap_pte_batch(folio, &pvmw, flags, pteval);
@@ -2308,8 +2370,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
*/
dec_mm_counter(mm, mm_counter(folio));
} else if (folio_test_anon(folio)) {
- swp_entry_t entry = page_swap_entry(subpage);
- pte_t swp_pte;
/*
* Store the swap location in the pte.
* See handle_pte_fault() ...
@@ -2331,52 +2391,12 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
goto finish_unmap;
}
- if (folio_dup_swap_pages(folio, subpage, 1) < 0) {
- set_pte_at(mm, address, pvmw.pte, pteval);
- goto walk_abort;
- }
-
- /*
- * arch_unmap_one() is expected to be a NOP on
- * architectures where we could have PFN swap PTEs,
- * so we'll not check/care.
- */
- if (arch_unmap_one(mm, vma, address, pteval) < 0) {
- folio_put_swap_pages(folio, subpage, 1);
- set_pte_at(mm, address, pvmw.pte, pteval);
- goto walk_abort;
- }
-
- /* See folio_try_share_anon_rmap(): clear PTE first. */
- if (anon_exclusive &&
- folio_try_share_anon_rmap_pte(folio, subpage)) {
- folio_put_swap_pages(folio, subpage, 1);
+ if (!ttu_anon_folio(vma, folio, subpage, address,
+ pvmw.pte, pteval)) {
set_pte_at(mm, address, pvmw.pte, pteval);
goto walk_abort;
}
- if (list_empty(&mm->mmlist)) {
- spin_lock(&mmlist_lock);
- if (list_empty(&mm->mmlist))
- list_add(&mm->mmlist, &init_mm.mmlist);
- spin_unlock(&mmlist_lock);
- }
- dec_mm_counter(mm, MM_ANONPAGES);
- inc_mm_counter(mm, MM_SWAPENTS);
- swp_pte = swp_entry_to_pte(entry);
- if (anon_exclusive)
- swp_pte = pte_swp_mkexclusive(swp_pte);
- if (likely(pte_present(pteval))) {
- if (pte_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_uffd_wp(pteval))
- swp_pte = pte_swp_mkuffd_wp(swp_pte);
- } else {
- if (pte_swp_soft_dirty(pteval))
- swp_pte = pte_swp_mksoft_dirty(swp_pte);
- if (pte_swp_uffd_wp(pteval))
- swp_pte = pte_swp_mkuffd_wp(swp_pte);
- }
- set_pte_at(mm, address, pvmw.pte, swp_pte);
+ goto finish_unmap;
} else {
/*
* This is a locked file-backed folio,
--
2.34.1
next prev parent reply other threads:[~2026-05-26 6:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-26 6:36 [PATCH v4 00/12] Optimize anonymous large folio unmapping Dev Jain
2026-05-26 6:36 ` [PATCH v4 01/12] mm/rmap: convert page -> folio for hwpoison checks Dev Jain
2026-05-26 6:36 ` [PATCH v4 02/12] mm/rmap: Add try_to_unmap_hugetlb_one Dev Jain
2026-05-26 6:36 ` [PATCH v4 03/12] mm/rmap: refactor some code around lazyfree folio unmapping Dev Jain
2026-05-26 6:36 ` [PATCH v4 04/12] mm/memory: Batch set uffd-wp markers during zapping Dev Jain
2026-05-26 6:36 ` [PATCH v4 05/12] mm/rmap: batch unmap folios belonging to uffd-wp VMAs Dev Jain
2026-05-26 6:36 ` [PATCH v4 06/12] mm/swap: rename subpage->page in folio_dup_swap/folio_put_swap Dev Jain
2026-05-26 6:36 ` [PATCH v4 07/12] mm/swapfile: Add batched version of folio_dup_swap Dev Jain
2026-05-26 6:36 ` [PATCH v4 08/12] mm/swapfile: Add batched version of folio_put_swap Dev Jain
2026-05-26 6:36 ` [PATCH v4 09/12] mm/rmap: Add batched version of folio_try_share_anon_rmap_pte Dev Jain
2026-05-26 6:36 ` Dev Jain [this message]
2026-05-26 6:36 ` [PATCH v4 11/12] mm/mprotect: drop 'sub' from page_anon_exclusive_sub_batch Dev Jain
2026-05-26 6:36 ` [PATCH v4 12/12] mm/rmap: enable batch unmapping of anonymous folios Dev Jain
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