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mm: convert do_wp_page() to use a folio

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Saves many calls to compound_head().

Link: https://lkml.kernel.org/r/20220902194653.1739778-42-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) 2022-09-02 20:46:37 +01:00 committed by Andrew Morton
parent 71fa1a533d
commit e4a2ed9490
1 changed files with 20 additions and 20 deletions
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40
mm/memory.c
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@ -3368,6 +3368,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
{
const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE;
struct vm_area_struct *vma = vmf->vma;
struct folio *folio;
VM_BUG_ON(unshare && (vmf->flags & FAULT_FLAG_WRITE));
VM_BUG_ON(!unshare && !(vmf->flags & FAULT_FLAG_WRITE));
@ -3414,48 +3415,47 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
* Take out anonymous pages first, anonymous shared vmas are
* not dirty accountable.
*/
if (PageAnon(vmf->page)) {
struct page *page = vmf->page;
folio = page_folio(vmf->page);
if (folio_test_anon(folio)) {
/*
* If the page is exclusive to this process we must reuse the
* page without further checks.
*/
if (PageAnonExclusive(page))
if (PageAnonExclusive(vmf->page))
goto reuse;
/*
* We have to verify under page lock: these early checks are
* just an optimization to avoid locking the page and freeing
* We have to verify under folio lock: these early checks are
* just an optimization to avoid locking the folio and freeing
* the swapcache if there is little hope that we can reuse.
*
* PageKsm() doesn't necessarily raise the page refcount.
* KSM doesn't necessarily raise the folio refcount.
*/
if (PageKsm(page) || page_count(page) > 3)
if (folio_test_ksm(folio) || folio_ref_count(folio) > 3)
goto copy;
if (!PageLRU(page))
if (!folio_test_lru(folio))
/*
* Note: We cannot easily detect+handle references from
* remote LRU pagevecs or references to PageLRU() pages.
* remote LRU pagevecs or references to LRU folios.
*/
lru_add_drain();
if (page_count(page) > 1 + PageSwapCache(page))
if (folio_ref_count(folio) > 1 + folio_test_swapcache(folio))
goto copy;
if (!trylock_page(page))
if (!folio_trylock(folio))
goto copy;
if (PageSwapCache(page))
try_to_free_swap(page);
if (PageKsm(page) || page_count(page) != 1) {
unlock_page(page);
if (folio_test_swapcache(folio))
folio_free_swap(folio);
if (folio_test_ksm(folio) || folio_ref_count(folio) != 1) {
folio_unlock(folio);
goto copy;
}
/*
* Ok, we've got the only page reference from our mapping
* and the page is locked, it's dark out, and we're wearing
* Ok, we've got the only folio reference from our mapping
* and the folio is locked, it's dark out, and we're wearing
* sunglasses. Hit it.
*/
page_move_anon_rmap(page, vma);
unlock_page(page);
page_move_anon_rmap(vmf->page, vma);
folio_unlock(folio);
reuse:
if (unlikely(unshare)) {
pte_unmap_unlock(vmf->pte, vmf->ptl);