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mm/ksm: use folio in write_protect_page

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Compound page is checked and skipped before write_protect_page() called,
use folio to save a few compound_head checks.

Link: https://lkml.kernel.org/r/20240411061713.1847574-8-alexs@kernel.org
Signed-off-by: Alex Shi (tencent) <alexs@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Alex Shi (tencent) 2024-04-11 14:17:08 +08:00 committed by Andrew Morton
parent 72556a4c06
commit 40d707f33d
1 changed files with 13 additions and 12 deletions
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25
mm/ksm.c
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@ -1289,23 +1289,24 @@ static u32 calc_checksum(struct page *page)
return checksum;
}
static int write_protect_page(struct vm_area_struct *vma, struct page *page,
static int write_protect_page(struct vm_area_struct *vma, struct folio *folio,
pte_t *orig_pte)
{
struct mm_struct *mm = vma->vm_mm;
DEFINE_PAGE_VMA_WALK(pvmw, page, vma, 0, 0);
DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, 0, 0);
int swapped;
int err = -EFAULT;
struct mmu_notifier_range range;
bool anon_exclusive;
pte_t entry;
pvmw.address = page_address_in_vma(page, vma);
if (WARN_ON_ONCE(folio_test_large(folio)))
return err;
pvmw.address = page_address_in_vma(&folio->page, vma);
if (pvmw.address == -EFAULT)
goto out;
BUG_ON(PageTransCompound(page));
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, pvmw.address,
pvmw.address + PAGE_SIZE);
mmu_notifier_invalidate_range_start(&range);
@ -1315,12 +1316,12 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?"))
goto out_unlock;
anon_exclusive = PageAnonExclusive(page);
anon_exclusive = PageAnonExclusive(&folio->page);
entry = ptep_get(pvmw.pte);
if (pte_write(entry) || pte_dirty(entry) ||
anon_exclusive || mm_tlb_flush_pending(mm)) {
swapped = PageSwapCache(page);
flush_cache_page(vma, pvmw.address, page_to_pfn(page));
swapped = folio_test_swapcache(folio);
flush_cache_page(vma, pvmw.address, folio_pfn(folio));
/*
* Ok this is tricky, when get_user_pages_fast() run it doesn't
* take any lock, therefore the check that we are going to make
@ -1340,20 +1341,20 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
* Check that no O_DIRECT or similar I/O is in progress on the
* page
*/
if (page_mapcount(page) + 1 + swapped != page_count(page)) {
if (folio_mapcount(folio) + 1 + swapped != folio_ref_count(folio)) {
set_pte_at(mm, pvmw.address, pvmw.pte, entry);
goto out_unlock;
}
/* See folio_try_share_anon_rmap_pte(): clear PTE first. */
if (anon_exclusive &&
folio_try_share_anon_rmap_pte(page_folio(page), page)) {
folio_try_share_anon_rmap_pte(folio, &folio->page)) {
set_pte_at(mm, pvmw.address, pvmw.pte, entry);
goto out_unlock;
}
if (pte_dirty(entry))
set_page_dirty(page);
folio_mark_dirty(folio);
entry = pte_mkclean(entry);
if (pte_write(entry))
@ -1519,7 +1520,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
* ptes are necessarily already write-protected. But in either
* case, we need to lock and check page_count is not raised.
*/
if (write_protect_page(vma, page, &orig_pte) == 0) {
if (write_protect_page(vma, page_folio(page), &orig_pte) == 0) {
if (!kpage) {
/*
* While we hold page lock, upgrade page from