[PATCH -next 1/2] mm: compaction: convert to use a folio in isolate_migratepages_block()

From: Kefeng Wang
Date: Mon Jun 12 2023 - 10:42:56 EST


Directly use a folio instead of page_folio() when page successfully
isolated (hugepage and movable page) and after folio_get_nontail_page(),
which removes several calls to compound_head().

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/compaction.c | 71 ++++++++++++++++++++++++++-----------------------
1 file changed, 38 insertions(+), 33 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 3398ef3a55fe..5d3f0aaa6785 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -831,6 +831,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
struct lruvec *lruvec;
unsigned long flags = 0;
struct lruvec *locked = NULL;
+ struct folio *folio = NULL;
struct page *page = NULL, *valid_page = NULL;
struct address_space *mapping;
unsigned long start_pfn = low_pfn;
@@ -927,7 +928,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
if (!valid_page && pageblock_aligned(low_pfn)) {
if (!isolation_suitable(cc, page)) {
low_pfn = end_pfn;
- page = NULL;
+ folio = NULL;
goto isolate_abort;
}
valid_page = page;
@@ -959,7 +960,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* Hugepage was successfully isolated and placed
* on the cc->migratepages list.
*/
- low_pfn += compound_nr(page) - 1;
+ folio = page_folio(page);
+ low_pfn += folio_nr_pages(folio) - 1;
goto isolate_success_no_list;
}

@@ -1027,8 +1029,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
locked = NULL;
}

- if (isolate_movable_page(page, mode))
+ if (isolate_movable_page(page, mode)) {
+ folio = page_folio(page);
goto isolate_success;
+ }
}

goto isolate_fail;
@@ -1039,7 +1043,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* sure the page is not being freed elsewhere -- the
* page release code relies on it.
*/
- if (unlikely(!get_page_unless_zero(page)))
+ folio = folio_get_nontail_page(page);
+ if (unlikely(!folio))
goto isolate_fail;

/*
@@ -1047,7 +1052,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* from long term pinning preventing it from migrating,
* so avoid taking lru_lock and isolating it unnecessarily.
*/
- mapping = page_mapping(page);
+ mapping = folio_mapping(folio);
if (!cc->alloc_contig && page_has_extra_refs(page, mapping))
goto isolate_fail_put;

@@ -1063,7 +1068,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
goto isolate_fail_put;

/* Compaction might skip unevictable pages but CMA takes them */
- if (!(mode & ISOLATE_UNEVICTABLE) && PageUnevictable(page))
+ if (!(mode & ISOLATE_UNEVICTABLE) && folio_test_unevictable(folio))
goto isolate_fail_put;

/*
@@ -1072,10 +1077,10 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* it will be able to migrate without blocking - clean pages
* for the most part. PageWriteback would require blocking.
*/
- if ((mode & ISOLATE_ASYNC_MIGRATE) && PageWriteback(page))
+ if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_writeback(folio))
goto isolate_fail_put;

- if ((mode & ISOLATE_ASYNC_MIGRATE) && PageDirty(page)) {
+ if ((mode & ISOLATE_ASYNC_MIGRATE) && folio_test_dirty(folio)) {
bool migrate_dirty;

/*
@@ -1087,22 +1092,22 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* the page lock until after the page is removed
* from the page cache.
*/
- if (!trylock_page(page))
+ if (!folio_trylock(folio))
goto isolate_fail_put;

- mapping = page_mapping(page);
+ mapping = folio_mapping(folio);
migrate_dirty = !mapping ||
mapping->a_ops->migrate_folio;
- unlock_page(page);
+ folio_unlock(folio);
if (!migrate_dirty)
goto isolate_fail_put;
}

/* Try isolate the page */
- if (!TestClearPageLRU(page))
+ if (!folio_test_clear_lru(folio))
goto isolate_fail_put;

- lruvec = folio_lruvec(page_folio(page));
+ lruvec = folio_lruvec(folio);

/* If we already hold the lock, we can skip some rechecking */
if (lruvec != locked) {
@@ -1112,7 +1117,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
locked = lruvec;

- lruvec_memcg_debug(lruvec, page_folio(page));
+ lruvec_memcg_debug(lruvec, folio);

/*
* Try get exclusive access under lock. If marked for
@@ -1132,30 +1137,30 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
* and it's on LRU. It can only be a THP so the order
* is safe to read and it's 0 for tail pages.
*/
- if (unlikely(PageCompound(page) && !cc->alloc_contig)) {
- low_pfn += compound_nr(page) - 1;
- nr_scanned += compound_nr(page) - 1;
- SetPageLRU(page);
+ if (unlikely(folio_test_large(folio) && !cc->alloc_contig)) {
+ low_pfn += folio_nr_pages(folio) - 1;
+ nr_scanned += folio_nr_pages(folio) - 1;
+ folio_set_lru(folio);
goto isolate_fail_put;
}
}

/* The whole page is taken off the LRU; skip the tail pages. */
- if (PageCompound(page))
- low_pfn += compound_nr(page) - 1;
+ if (folio_test_large(folio))
+ low_pfn += folio_nr_pages(folio) - 1;

/* Successfully isolated */
- del_page_from_lru_list(page, lruvec);
- mod_node_page_state(page_pgdat(page),
- NR_ISOLATED_ANON + page_is_file_lru(page),
- thp_nr_pages(page));
+ lruvec_del_folio(lruvec, folio);
+ mod_node_page_state(folio_pgdat(folio),
+ NR_ISOLATED_ANON + folio_is_file_lru(folio),
+ folio_nr_pages(folio));

isolate_success:
- list_add(&page->lru, &cc->migratepages);
+ list_add(&folio->lru, &cc->migratepages);
isolate_success_no_list:
- cc->nr_migratepages += compound_nr(page);
- nr_isolated += compound_nr(page);
- nr_scanned += compound_nr(page) - 1;
+ cc->nr_migratepages += folio_nr_pages(folio);
+ nr_isolated += folio_nr_pages(folio);
+ nr_scanned += folio_nr_pages(folio) - 1;

/*
* Avoid isolating too much unless this block is being
@@ -1177,7 +1182,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
unlock_page_lruvec_irqrestore(locked, flags);
locked = NULL;
}
- put_page(page);
+ folio_put(folio);

isolate_fail:
if (!skip_on_failure && ret != -ENOMEM)
@@ -1218,14 +1223,14 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
if (unlikely(low_pfn > end_pfn))
low_pfn = end_pfn;

- page = NULL;
+ folio = NULL;

isolate_abort:
if (locked)
unlock_page_lruvec_irqrestore(locked, flags);
- if (page) {
- SetPageLRU(page);
- put_page(page);
+ if (folio) {
+ folio_set_lru(folio);
+ folio_put(folio);
}

/*
--
2.35.3