The patch titled
Subject: mm: convert unuse_pte() to use a folio throughout
has been added to the -mm mm-unstable branch. Its filename is
mm-convert-unuse_pte-to-use-a-folio-throughout.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-convert-unuse_pte-to-use-a-folio-throughout.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: convert unuse_pte() to use a folio throughout
Date: Mon, 11 Dec 2023 16:22:08 +0000
Saves about eight calls to compound_head().
Link: https://lkml.kernel.org/r/20231211162214.2146080-4-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 47 +++++++++++++++++++++++++----------------------
1 file changed, 25 insertions(+), 22 deletions(-)
--- a/mm/swapfile.c~mm-convert-unuse_pte-to-use-a-folio-throughout
+++ a/mm/swapfile.c
@@ -1741,21 +1741,25 @@ static inline int pte_same_as_swp(pte_t
static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, swp_entry_t entry, struct folio *folio)
{
- struct page *page = folio_file_page(folio, swp_offset(entry));
- struct page *swapcache;
+ struct page *page;
+ struct folio *swapcache;
spinlock_t *ptl;
pte_t *pte, new_pte, old_pte;
- bool hwpoisoned = PageHWPoison(page);
+ bool hwpoisoned = false;
int ret = 1;
- swapcache = page;
+ swapcache = folio;
folio = ksm_might_need_to_copy(folio, vma, addr);
if (unlikely(!folio))
return -ENOMEM;
- else if (unlikely(folio == ERR_PTR(-EHWPOISON)))
+ else if (unlikely(folio == ERR_PTR(-EHWPOISON))) {
+ hwpoisoned = true;
+ folio = swapcache;
+ }
+
+ page = folio_file_page(folio, swp_offset(entry));
+ if (PageHWPoison(page))
hwpoisoned = true;
- else
- page = folio_file_page(folio, swp_offset(entry));
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte),
@@ -1766,13 +1770,12 @@ static int unuse_pte(struct vm_area_stru
old_pte = ptep_get(pte);
- if (unlikely(hwpoisoned || !PageUptodate(page))) {
+ if (unlikely(hwpoisoned || !folio_test_uptodate(folio))) {
swp_entry_t swp_entry;
dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
if (hwpoisoned) {
- swp_entry = make_hwpoison_entry(swapcache);
- page = swapcache;
+ swp_entry = make_hwpoison_entry(page);
} else {
swp_entry = make_poisoned_swp_entry();
}
@@ -1786,7 +1789,7 @@ static int unuse_pte(struct vm_area_stru
* when reading from swap. This metadata may be indexed by swap entry
* so this must be called before swap_free().
*/
- arch_swap_restore(entry, page_folio(page));
+ arch_swap_restore(entry, folio);
/* See do_swap_page() */
VM_BUG_ON_FOLIO(!folio_test_anon(folio), folio);
@@ -1794,23 +1797,23 @@ static int unuse_pte(struct vm_area_stru
dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
- get_page(page);
- if (page == swapcache) {
+ folio_get(folio);
+ if (folio == swapcache) {
rmap_t rmap_flags = RMAP_NONE;
/*
- * See do_swap_page(): PageWriteback() would be problematic.
- * However, we do a wait_on_page_writeback() just before this
- * call and have the page locked.
+ * See do_swap_page(): writeback would be problematic.
+ * However, we do a folio_wait_writeback() just before this
+ * call and have the folio locked.
*/
- VM_BUG_ON_PAGE(PageWriteback(page), page);
+ VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio);
if (pte_swp_exclusive(old_pte))
rmap_flags |= RMAP_EXCLUSIVE;
page_add_anon_rmap(page, vma, addr, rmap_flags);
} else { /* ksm created a completely new copy */
- page_add_new_anon_rmap(page, vma, addr);
- lru_cache_add_inactive_or_unevictable(page, vma);
+ folio_add_new_anon_rmap(folio, vma, addr);
+ folio_add_lru_vma(folio, vma);
}
new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot));
if (pte_swp_soft_dirty(old_pte))
@@ -1823,9 +1826,9 @@ setpte:
out:
if (pte)
pte_unmap_unlock(pte, ptl);
- if (page != swapcache) {
- unlock_page(page);
- put_page(page);
+ if (folio != swapcache) {
+ folio_unlock(folio);
+ folio_put(folio);
}
return ret;
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
buffer-return-bool-from-grow_dev_folio.patch
buffer-calculate-block-number-inside-folio_init_buffers.patch
buffer-fix-grow_buffers-for-block-size-page_size.patch
buffer-cast-block-to-loff_t-before-shifting-it.patch
buffer-fix-various-functions-for-block-size-page_size.patch
buffer-handle-large-folios-in-__block_write_begin_int.patch
buffer-fix-more-functions-for-block-size-page_size.patch
mm-convert-ksm_might_need_to_copy-to-work-on-folios.patch
mm-simplify-the-assertions-in-unuse_pte.patch
mm-convert-unuse_pte-to-use-a-folio-throughout.patch
mm-remove-some-calls-to-page_add_new_anon_rmap.patch
mm-remove-stale-example-from-comment.patch
mm-remove-references-to-page_add_new_anon_rmap-in-comments.patch
mm-convert-migrate_vma_insert_page-to-use-a-folio.patch
mm-convert-collapse_huge_page-to-use-a-folio.patch
mm-remove-page_add_new_anon_rmap-and-lru_cache_add_inactive_or_unevictable.patch
