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mm: convert unuse_pte() to use a folio throughout 

Saves about eight calls to compound_head().

Link: https://lkml.kernel.org/r/20231211162214.2146080-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-12-11 16:22:08 +00:00 committed by Andrew Morton
parent 8d294a8c63
commit f00f48436c
1 changed files with 25 additions and 22 deletions
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47
mm/swapfile.c
View File

@ -1741,21 +1741,25 @@ static inline int pte_same_as_swp(pte_t pte, pte_t swp_pte)
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_struct *vma, pmd_t *pmd,
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();
}
@ -1786,27 +1789,27 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
* 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);
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))
@ -1819,9 +1822,9 @@ 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;
}