[PATCH 01/11] mm/ksm: Convert get_ksm_page to return a folio

alexs
2024-03-20T07:37:40Z

The ksm only contains single pages, so use folio instead of pages to
save a couple of compound_head calls.

Signed-off-by: Alex Shi (tencent) <alexs@kernel.org>
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>
---
mm/ksm.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 8c001819cf10..fda291b054c2 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -915,10 +915,10 @@ enum get_ksm_page_flags {
* a page to put something that might look like our key in page->mapping.
* is on its way to being freed; but it is an anomaly to bear in mind.
*/
-static struct page *get_ksm_page(struct ksm_stable_node *stable_node,
+static void *get_ksm_page(struct ksm_stable_node *stable_node,
enum get_ksm_page_flags flags)
{
- struct page *page;
+ struct folio *folio;
void *expected_mapping;
unsigned long kpfn;

@@ -926,8 +926,8 @@ static struct page *get_ksm_page(struct ksm_stable_node *stable_node,
PAGE_MAPPING_KSM);
again:
kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */
- page = pfn_to_page(kpfn);
- if (READ_ONCE(page->mapping) != expected_mapping)
+ folio = pfn_folio(kpfn);
+ if (READ_ONCE(folio->mapping) != expected_mapping)
goto stale;

/*
@@ -940,7 +940,7 @@ static struct page *get_ksm_page(struct ksm_stable_node *stable_node,
* in folio_migrate_mapping(), it might still be our page,
* in which case it's essential to keep the node.
*/
- while (!get_page_unless_zero(page)) {
+ while (!folio_try_get(folio)) {
/*
* Another check for page->mapping != expected_mapping would
* work here too. We have chosen the !PageSwapCache test to
@@ -949,32 +949,32 @@ static struct page *get_ksm_page(struct ksm_stable_node *stable_node,
* in the ref_freeze section of __remove_mapping(); but Anon
* page->mapping reset to NULL later, in free_pages_prepare().
*/
- if (!PageSwapCache(page))
+ if (!folio_test_swapcache(folio))
goto stale;
cpu_relax();
}

- if (READ_ONCE(page->mapping) != expected_mapping) {
- put_page(page);
+ if (READ_ONCE(folio->mapping) != expected_mapping) {
+ folio_put(folio);
goto stale;
}

if (flags == GET_KSM_PAGE_TRYLOCK) {
- if (!trylock_page(page)) {
- put_page(page);
+ if (!folio_trylock(folio)) {
+ folio_put(folio);
return ERR_PTR(-EBUSY);
}
} else if (flags == GET_KSM_PAGE_LOCK)
- lock_page(page);
+ folio_lock(folio);

if (flags != GET_KSM_PAGE_NOLOCK) {
- if (READ_ONCE(page->mapping) != expected_mapping) {
- unlock_page(page);
- put_page(page);
+ if (READ_ONCE(folio->mapping) != expected_mapping) {
+ folio_unlock(folio);
+ folio_put(folio);
goto stale;
}
}
- return page;
+ return folio;

stale:
/*
--
2.43.0