mm: page_idle: convert page idle to use a folio

Firstly, make page_idle_get_page() return a folio, also rename it to
page_idle_get_folio(), then, use it to convert page_idle_bitmap_read() and
page_idle_bitmap_write() functions.

Link: https://lkml.kernel.org/r/20221230070849.63358-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_idle.c b/mm/page_idle.c
index bc08332..41ea77f 100644 (file)
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -31,19 +31,22 @@
  *
  * This function tries to get a user memory page by pfn as described above.
  */
-static struct page *page_idle_get_page(unsigned long pfn)
+static struct folio *page_idle_get_folio(unsigned long pfn)
 {
        struct page *page = pfn_to_online_page(pfn);
+       struct folio *folio;
 
-       if (!page || !PageLRU(page) ||
-           !get_page_unless_zero(page))
+       if (!page || PageTail(page))
                return NULL;
 
-       if (unlikely(!PageLRU(page))) {
-               put_page(page);
-               page = NULL;
+       folio = page_folio(page);
+       if (!folio_test_lru(folio) || !folio_try_get(folio))
+               return NULL;
+       if (unlikely(page_folio(page) != folio || !folio_test_lru(folio))) {
+               folio_put(folio);
+               folio = NULL;
        }
-       return page;
+       return folio;
 }
 
 static bool page_idle_clear_pte_refs_one(struct folio *folio,
@@ -83,10 +86,8 @@ static bool page_idle_clear_pte_refs_one(struct folio *folio,
        return true;
 }
 
-static void page_idle_clear_pte_refs(struct page *page)
+static void page_idle_clear_pte_refs(struct folio *folio)
 {
-       struct folio *folio = page_folio(page);
-
        /*
         * Since rwc.try_lock is unused, rwc is effectively immutable, so we
         * can make it static to save some cycles and stack.
@@ -115,7 +116,7 @@ static ssize_t page_idle_bitmap_read(struct file *file, struct kobject *kobj,
                                     loff_t pos, size_t count)
 {
        u64 *out = (u64 *)buf;
-       struct page *page;
+       struct folio *folio;
        unsigned long pfn, end_pfn;
        int bit;
 
@@ -134,19 +135,19 @@ static ssize_t page_idle_bitmap_read(struct file *file, struct kobject *kobj,
                bit = pfn % BITMAP_CHUNK_BITS;
                if (!bit)
                        *out = 0ULL;
-               page = page_idle_get_page(pfn);
-               if (page) {
-                       if (page_is_idle(page)) {
+               folio = page_idle_get_folio(pfn);
+               if (folio) {
+                       if (folio_test_idle(folio)) {
                                /*
                                 * The page might have been referenced via a
                                 * pte, in which case it is not idle. Clear
                                 * refs and recheck.
                                 */
-                               page_idle_clear_pte_refs(page);
-                               if (page_is_idle(page))
+                               page_idle_clear_pte_refs(folio);
+                               if (folio_test_idle(folio))
                                        *out |= 1ULL << bit;
                        }
-                       put_page(page);
+                       folio_put(folio);
                }
                if (bit == BITMAP_CHUNK_BITS - 1)
                        out++;
@@ -160,7 +161,7 @@ static ssize_t page_idle_bitmap_write(struct file *file, struct kobject *kobj,
                                      loff_t pos, size_t count)
 {
        const u64 *in = (u64 *)buf;
-       struct page *page;
+       struct folio *folio;
        unsigned long pfn, end_pfn;
        int bit;
 
@@ -178,11 +179,11 @@ static ssize_t page_idle_bitmap_write(struct file *file, struct kobject *kobj,
        for (; pfn < end_pfn; pfn++) {
                bit = pfn % BITMAP_CHUNK_BITS;
                if ((*in >> bit) & 1) {
-                       page = page_idle_get_page(pfn);
-                       if (page) {
-                               page_idle_clear_pte_refs(page);
-                               set_page_idle(page);
-                               put_page(page);
+                       folio = page_idle_get_folio(pfn);
+                       if (folio) {
+                               page_idle_clear_pte_refs(folio);
+                               folio_set_idle(folio);
+                               folio_put(folio);
                        }
                }
                if (bit == BITMAP_CHUNK_BITS - 1)