[PATCH RFC 1/3] mm: extend rmap flags arguments for folio_add_new_anon_rmap
From: Barry Song
Date: Wed Jun 12 2024 - 20:08:10 EST
From: Barry Song <v-songbaohua@xxxxxxxx>
In the case of do_swap_page(), a new anonymous folio isn’t necessarily
exclusive. This patch extends the rmap flags to allow treating a new
anon folio as either exclusive or non-exclusive. To maintain the current
behavior, we always use EXCLUSIVE as arguments.
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
---
include/linux/rmap.h | 2 +-
kernel/events/uprobes.c | 2 +-
mm/huge_memory.c | 2 +-
mm/khugepaged.c | 2 +-
mm/memory.c | 10 +++++-----
mm/migrate_device.c | 2 +-
mm/rmap.c | 15 +++++++++------
mm/swapfile.c | 2 +-
mm/userfaultfd.c | 2 +-
9 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index cae38a2a643d..01a64e7e72b9 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -244,7 +244,7 @@ void folio_add_anon_rmap_ptes(struct folio *, struct page *, int nr_pages,
void folio_add_anon_rmap_pmd(struct folio *, struct page *,
struct vm_area_struct *, unsigned long address, rmap_t flags);
void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
- unsigned long address);
+ unsigned long address, rmap_t flags);
void folio_add_file_rmap_ptes(struct folio *, struct page *, int nr_pages,
struct vm_area_struct *);
#define folio_add_file_rmap_pte(folio, page, vma) \
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 2c83ba776fc7..c20368aa33dd 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -181,7 +181,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
if (new_page) {
folio_get(new_folio);
- folio_add_new_anon_rmap(new_folio, vma, addr);
+ folio_add_new_anon_rmap(new_folio, vma, addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(new_folio, vma);
} else
/* no new page, just dec_mm_counter for old_page */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f409ea9fcc18..09a83e43c71a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -973,7 +973,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
entry = mk_huge_pmd(page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
- folio_add_new_anon_rmap(folio, vma, haddr);
+ folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 774a97e6e2da..4d759a7487d0 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1213,7 +1213,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
spin_lock(pmd_ptl);
BUG_ON(!pmd_none(*pmd));
- folio_add_new_anon_rmap(folio, vma, address);
+ folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
pgtable_trans_huge_deposit(mm, pmd, pgtable);
set_pmd_at(mm, address, pmd, _pmd);
diff --git a/mm/memory.c b/mm/memory.c
index 54d7d2acdf39..2f94921091fb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -930,7 +930,7 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
*prealloc = NULL;
copy_user_highpage(&new_folio->page, page, addr, src_vma);
__folio_mark_uptodate(new_folio);
- folio_add_new_anon_rmap(new_folio, dst_vma, addr);
+ folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(new_folio, dst_vma);
rss[MM_ANONPAGES]++;
@@ -3400,7 +3400,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
* some TLBs while the old PTE remains in others.
*/
ptep_clear_flush(vma, vmf->address, vmf->pte);
- folio_add_new_anon_rmap(new_folio, vma, vmf->address);
+ folio_add_new_anon_rmap(new_folio, vma, vmf->address, RMAP_EXCLUSIVE);
folio_add_lru_vma(new_folio, vma);
BUG_ON(unshare && pte_write(entry));
set_pte_at(mm, vmf->address, vmf->pte, entry);
@@ -4337,7 +4337,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
/* ksm created a completely new copy */
if (unlikely(folio != swapcache && swapcache)) {
- folio_add_new_anon_rmap(folio, vma, address);
+ folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
} else {
folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address,
@@ -4592,7 +4592,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_FAULT_ALLOC);
#endif
- folio_add_new_anon_rmap(folio, vma, addr);
+ folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
setpte:
if (vmf_orig_pte_uffd_wp(vmf))
@@ -4790,7 +4790,7 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
/* copy-on-write page */
if (write && !(vma->vm_flags & VM_SHARED)) {
VM_BUG_ON_FOLIO(nr != 1, folio);
- folio_add_new_anon_rmap(folio, vma, addr);
+ folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
} else {
folio_add_file_rmap_ptes(folio, page, nr, vma);
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 051d0a3ccbee..6d66dc1c6ffa 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -658,7 +658,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
goto unlock_abort;
inc_mm_counter(mm, MM_ANONPAGES);
- folio_add_new_anon_rmap(folio, vma, addr);
+ folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE);
if (!folio_is_zone_device(folio))
folio_add_lru_vma(folio, vma);
folio_get(folio);
diff --git a/mm/rmap.c b/mm/rmap.c
index b9e5943c8349..e612d999811a 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1406,14 +1406,14 @@ void folio_add_anon_rmap_pmd(struct folio *folio, struct page *page,
* This means the inc-and-test can be bypassed.
* The folio does not have to be locked.
*
- * If the folio is pmd-mappable, it is accounted as a THP. As the folio
- * is new, it's assumed to be mapped exclusively by a single process.
+ * If the folio is pmd-mappable, it is accounted as a THP.
*/
void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
- unsigned long address)
+ unsigned long address, rmap_t flags)
{
int nr = folio_nr_pages(folio);
int nr_pmdmapped = 0;
+ bool exclusive = flags & RMAP_EXCLUSIVE;
VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_BUG_ON_VMA(address < vma->vm_start ||
@@ -1424,7 +1424,8 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
if (likely(!folio_test_large(folio))) {
/* increment count (starts at -1) */
atomic_set(&folio->_mapcount, 0);
- SetPageAnonExclusive(&folio->page);
+ if (exclusive)
+ SetPageAnonExclusive(&folio->page);
} else if (!folio_test_pmd_mappable(folio)) {
int i;
@@ -1433,7 +1434,8 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
/* increment count (starts at -1) */
atomic_set(&page->_mapcount, 0);
- SetPageAnonExclusive(page);
+ if (exclusive)
+ SetPageAnonExclusive(page);
}
/* increment count (starts at -1) */
@@ -1445,7 +1447,8 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
/* increment count (starts at -1) */
atomic_set(&folio->_large_mapcount, 0);
atomic_set(&folio->_nr_pages_mapped, ENTIRELY_MAPPED);
- SetPageAnonExclusive(&folio->page);
+ if (exclusive)
+ SetPageAnonExclusive(&folio->page);
nr_pmdmapped = nr;
}
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9c6d8e557c0f..ae1d2700f6a3 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1911,7 +1911,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
folio_add_anon_rmap_pte(folio, page, vma, addr, rmap_flags);
} else { /* ksm created a completely new copy */
- folio_add_new_anon_rmap(folio, vma, addr);
+ folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, vma);
}
new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot));
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 5e7f2801698a..8dedaec00486 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -216,7 +216,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd,
folio_add_lru(folio);
folio_add_file_rmap_pte(folio, page, dst_vma);
} else {
- folio_add_new_anon_rmap(folio, dst_vma, dst_addr);
+ folio_add_new_anon_rmap(folio, dst_vma, dst_addr, RMAP_EXCLUSIVE);
folio_add_lru_vma(folio, dst_vma);
}
--
2.34.1