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mm/rmap: Convert try_to_migrate() to folios 

Convert the callers to pass a folio and the try_to_migrate_one()
worker to use a folio throughout.  Fixes an assumption that a
folio must be <= PMD size.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-01-28 14:29:43 -05:00
parent 869f7ee6f6
commit 4b8554c527
5 changed files with 42 additions and 35 deletions
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2
include/linux/rmap.h
View File

@ -193,7 +193,7 @@ static inline void page_dup_rmap(struct page *page, bool compound)
int folio_referenced(struct folio *, int is_locked,
struct mem_cgroup *memcg, unsigned long *vm_flags);
void try_to_migrate(struct page *page, enum ttu_flags flags);
void try_to_migrate(struct folio *folio, enum ttu_flags flags);
void try_to_unmap(struct folio *, enum ttu_flags flags);
int make_device_exclusive_range(struct mm_struct *mm, unsigned long start,

4
mm/huge_memory.c
View File

@ -2262,8 +2262,8 @@ static void unmap_page(struct page *page)
* pages can simply be left unmapped, then faulted back on demand.
* If that is ever changed (perhaps for mlock), update remap_page().
*/
if (PageAnon(page))
try_to_migrate(page, ttu_flags);
if (folio_test_anon(folio))
try_to_migrate(folio, ttu_flags);
else
try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK);

6
mm/migrate.c
View File

@ -912,6 +912,7 @@ static int move_to_new_page(struct page *newpage, struct page *page,
static int __unmap_and_move(struct page *page, struct page *newpage,
int force, enum migrate_mode mode)
{
struct folio *folio = page_folio(page);
int rc = -EAGAIN;
bool page_was_mapped = false;
struct anon_vma *anon_vma = NULL;
@ -1015,7 +1016,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
/* Establish migration ptes */
VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
page);
try_to_migrate(page, 0);
try_to_migrate(folio, 0);
page_was_mapped = true;
}
@ -1165,6 +1166,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
enum migrate_mode mode, int reason,
struct list_head *ret)
{
struct folio *src = page_folio(hpage);
int rc = -EAGAIN;
int page_was_mapped = 0;
struct page *new_hpage;
@ -1241,7 +1243,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
ttu |= TTU_RMAP_LOCKED;
}
try_to_migrate(hpage, ttu);
try_to_migrate(src, ttu);
page_was_mapped = 1;
if (mapping_locked)

6
mm/migrate_device.c
View File

@ -333,6 +333,7 @@ static void migrate_vma_unmap(struct migrate_vma *migrate)
for (i = 0; i < npages; i++) {
struct page *page = migrate_pfn_to_page(migrate->src[i]);
struct folio *folio;
if (!page)
continue;
@ -356,8 +357,9 @@ static void migrate_vma_unmap(struct migrate_vma *migrate)
put_page(page);
}
if (page_mapped(page))
try_to_migrate(page, 0);
folio = page_folio(page);
if (folio_mapped(folio))
try_to_migrate(folio, 0);
if (page_mapped(page) || !migrate_vma_check_page(page)) {
if (!is_zone_device_page(page)) {

59
mm/rmap.c
View File

@ -1706,7 +1706,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
{
struct folio *folio = page_folio(page);
struct mm_struct *mm = vma->vm_mm;
DEFINE_PAGE_VMA_WALK(pvmw, page, vma, address, 0);
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0);
pte_t pteval;
struct page *subpage;
bool ret = true;
@ -1740,7 +1740,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
range.end = vma_address_end(&pvmw);
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
address, range.end);
if (PageHuge(page)) {
if (folio_test_hugetlb(folio)) {
/*
* If sharing is possible, start and end will be adjusted
* accordingly.
@ -1754,21 +1754,24 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
/* PMD-mapped THP migration entry */
if (!pvmw.pte) {
VM_BUG_ON_PAGE(PageHuge(page) ||
!PageTransCompound(page), page);
subpage = folio_page(folio,
pmd_pfn(*pvmw.pmd) - folio_pfn(folio));
VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) ||
!folio_test_pmd_mappable(folio), folio);
set_pmd_migration_entry(&pvmw, page);
set_pmd_migration_entry(&pvmw, subpage);
continue;
}
#endif
/* Unexpected PMD-mapped THP? */
VM_BUG_ON_PAGE(!pvmw.pte, page);
VM_BUG_ON_FOLIO(!pvmw.pte, folio);
subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte);
subpage = folio_page(folio,
pte_pfn(*pvmw.pte) - folio_pfn(folio));
address = pvmw.address;
if (PageHuge(page) && !PageAnon(page)) {
if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) {
/*
* To call huge_pmd_unshare, i_mmap_rwsem must be
* held in write mode. Caller needs to explicitly
@ -1806,15 +1809,15 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
flush_cache_page(vma, address, pte_pfn(*pvmw.pte));
pteval = ptep_clear_flush(vma, address, pvmw.pte);
/* Move the dirty bit to the page. Now the pte is gone. */
/* Set the dirty flag on the folio now the pte is gone. */
if (pte_dirty(pteval))
set_page_dirty(page);
folio_mark_dirty(folio);
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);
if (is_zone_device_page(page)) {
unsigned long pfn = page_to_pfn(page);
if (folio_is_zone_device(folio)) {
unsigned long pfn = folio_pfn(folio);
swp_entry_t entry;
pte_t swp_pte;
@ -1850,16 +1853,16 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
* changed when hugepage migrations to device private
* memory are supported.
*/
subpage = page;
} else if (PageHWPoison(page)) {
subpage = &folio->page;
} else if (PageHWPoison(subpage)) {
pteval = swp_entry_to_pte(make_hwpoison_entry(subpage));
if (PageHuge(page)) {
hugetlb_count_sub(compound_nr(page), mm);
if (folio_test_hugetlb(folio)) {
hugetlb_count_sub(folio_nr_pages(folio), mm);
set_huge_swap_pte_at(mm, address,
pvmw.pte, pteval,
vma_mmu_pagesize(vma));
} else {
dec_mm_counter(mm, mm_counter(page));
dec_mm_counter(mm, mm_counter(&folio->page));
set_pte_at(mm, address, pvmw.pte, pteval);
}
@ -1874,7 +1877,7 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
* migration) will not expect userfaults on already
* copied pages.
*/
dec_mm_counter(mm, mm_counter(page));
dec_mm_counter(mm, mm_counter(&folio->page));
/* We have to invalidate as we cleared the pte */
mmu_notifier_invalidate_range(mm, address,
address + PAGE_SIZE);
@ -1920,10 +1923,10 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
*
* See Documentation/vm/mmu_notifier.rst
*/
page_remove_rmap(subpage, vma, PageHuge(page));
page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
if (vma->vm_flags & VM_LOCKED)
mlock_page_drain(smp_processor_id());
put_page(page);
folio_put(folio);
}
mmu_notifier_invalidate_range_end(&range);
@ -1933,13 +1936,13 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
/**
* try_to_migrate - try to replace all page table mappings with swap entries
* @page: the page to replace page table entries for
* @folio: the folio to replace page table entries for
* @flags: action and flags
*
* Tries to remove all the page table entries which are mapping this page and
* replace them with special swap entries. Caller must hold the page lock.
* Tries to remove all the page table entries which are mapping this folio and
* replace them with special swap entries. Caller must hold the folio lock.
*/
void try_to_migrate(struct page *page, enum ttu_flags flags)
void try_to_migrate(struct folio *folio, enum ttu_flags flags)
{
struct rmap_walk_control rwc = {
.rmap_one = try_to_migrate_one,
@ -1956,7 +1959,7 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
TTU_SYNC)))
return;
if (is_zone_device_page(page) && !is_device_private_page(page))
if (folio_is_zone_device(folio) && !folio_is_device_private(folio))
return;
/*
@ -1967,13 +1970,13 @@ void try_to_migrate(struct page *page, enum ttu_flags flags)
* locking requirements of exec(), migration skips
* temporary VMAs until after exec() completes.
*/
if (!PageKsm(page) && PageAnon(page))
if (!folio_test_ksm(folio) && folio_test_anon(folio))
rwc.invalid_vma = invalid_migration_vma;
if (flags & TTU_RMAP_LOCKED)
rmap_walk_locked(page, &rwc);
rmap_walk_locked(&folio->page, &rwc);
else
rmap_walk(page, &rwc);
rmap_walk(&folio->page, &rwc);
}
#ifdef CONFIG_DEVICE_PRIVATE