[PATCH 1/3] madvise: Convert madvise_cold_or_pageout_pte_range() to use folios

From: Vishal Moola (Oracle)
Date: Tue Dec 06 2022 - 19:22:29 EST


This change removes a number of calls to compound_head(), and saves 1319
bytes of kernel text.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
---
mm/madvise.c | 88 +++++++++++++++++++++++++++-------------------------
1 file changed, 45 insertions(+), 43 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 2baa93ca2310..59bfc6c9c548 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -332,8 +332,9 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
struct vm_area_struct *vma = walk->vma;
pte_t *orig_pte, *pte, ptent;
spinlock_t *ptl;
+ struct folio *folio = NULL;
struct page *page = NULL;
- LIST_HEAD(page_list);
+ LIST_HEAD(folio_list);

if (fatal_signal_pending(current))
return -EINTR;
@@ -358,23 +359,23 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
goto huge_unlock;
}

- page = pmd_page(orig_pmd);
+ folio = pfn_folio(pmd_pfn(orig_pmd));

- /* Do not interfere with other mappings of this page */
- if (page_mapcount(page) != 1)
+ /* Do not interfere with other mappings of this folio */
+ if (folio_mapcount(folio) != 1)
goto huge_unlock;

if (next - addr != HPAGE_PMD_SIZE) {
int err;

- get_page(page);
+ folio_get(folio);
spin_unlock(ptl);
- lock_page(page);
- err = split_huge_page(page);
- unlock_page(page);
- put_page(page);
+ folio_lock(folio);
+ err = split_folio(folio);
+ folio_unlock(folio);
+ folio_put(folio);
if (!err)
- goto regular_page;
+ goto regular_folio;
return 0;
}

@@ -386,25 +387,25 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
}

- ClearPageReferenced(page);
- test_and_clear_page_young(page);
+ folio_clear_referenced(folio);
+ folio_test_clear_young(folio);
if (pageout) {
- if (!isolate_lru_page(page)) {
- if (PageUnevictable(page))
- putback_lru_page(page);
+ if (!folio_isolate_lru(folio)) {
+ if (folio_test_unevictable(folio))
+ folio_putback_lru(folio);
else
- list_add(&page->lru, &page_list);
+ list_add(&folio->lru, &folio_list);
}
} else
- deactivate_page(page);
+ deactivate_page(&folio->page);
huge_unlock:
spin_unlock(ptl);
if (pageout)
- reclaim_pages(&page_list);
+ reclaim_pages(&folio_list);
return 0;
}

-regular_page:
+regular_folio:
if (pmd_trans_unstable(pmd))
return 0;
#endif
@@ -424,28 +425,29 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
page = vm_normal_page(vma, addr, ptent);
if (!page || is_zone_device_page(page))
continue;
+ folio = page_folio(page);

/*
* Creating a THP page is expensive so split it only if we
* are sure it's worth. Split it if we are only owner.
*/
- if (PageTransCompound(page)) {
- if (page_mapcount(page) != 1)
+ if (folio_test_large(folio)) {
+ if (folio_mapcount(folio) != 1)
break;
- get_page(page);
- if (!trylock_page(page)) {
- put_page(page);
+ folio_get(folio);
+ if (!folio_trylock(folio)) {
+ folio_put(folio);
break;
}
pte_unmap_unlock(orig_pte, ptl);
- if (split_huge_page(page)) {
- unlock_page(page);
- put_page(page);
+ if (split_folio(folio)) {
+ folio_unlock(folio);
+ folio_put(folio);
orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
break;
}
- unlock_page(page);
- put_page(page);
+ folio_unlock(folio);
+ folio_put(folio);
orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
pte--;
addr -= PAGE_SIZE;
@@ -453,13 +455,13 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
}

/*
- * Do not interfere with other mappings of this page and
- * non-LRU page.
+ * Do not interfere with other mappings of this folio and
+ * non-LRU folio.
*/
- if (!PageLRU(page) || page_mapcount(page) != 1)
+ if (!folio_test_lru(folio))
continue;

- VM_BUG_ON_PAGE(PageTransCompound(page), page);
+ VM_BUG_ON_PAGE(folio_test_large(folio), folio);

if (pte_young(ptent)) {
ptent = ptep_get_and_clear_full(mm, addr, pte,
@@ -470,28 +472,28 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
}

/*
- * We are deactivating a page for accelerating reclaiming.
- * VM couldn't reclaim the page unless we clear PG_young.
+ * We are deactivating a folio for accelerating reclaiming.
+ * VM couldn't reclaim the folio unless we clear PG_young.
* As a side effect, it makes confuse idle-page tracking
* because they will miss recent referenced history.
*/
- ClearPageReferenced(page);
- test_and_clear_page_young(page);
+ folio_clear_referenced(folio);
+ folio_test_clear_young(folio);
if (pageout) {
- if (!isolate_lru_page(page)) {
- if (PageUnevictable(page))
- putback_lru_page(page);
+ if (!folio_isolate_lru(folio)) {
+ if (folio_test_unevictable(folio))
+ folio_putback_lru(folio);
else
- list_add(&page->lru, &page_list);
+ list_add(&folio->lru, &folio_list);
}
} else
- deactivate_page(page);
+ deactivate_page(&folio->page);
}

arch_leave_lazy_mmu_mode();
pte_unmap_unlock(orig_pte, ptl);
if (pageout)
- reclaim_pages(&page_list);
+ reclaim_pages(&folio_list);
cond_resched();

return 0;
--
2.38.1