diff mbox series

[1/4] mm: migrate: add folio_isolate_movable()

Message ID 20240826040132.1202297-2-wangkefeng.wang@huawei.com (mailing list archive)
State New
Headers show
Series mm: convert to folio_isolate_movable() | expand

Commit Message

Kefeng Wang Aug. 26, 2024, 4:01 a.m. UTC 
Like isolate_lru_page(), make isolate_movable_page() as a wrapper
around folio_isolate_movable(), since isolate_movable_page() always
fails on a tail page, return immediately for a tail page in the warpper,
and the wrapper will be removed once all callers are converted to
folio_isolate_movable().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/migrate.h |  4 ++++
 mm/migrate.c            | 41 ++++++++++++++++++++++++-----------------
 2 files changed, 28 insertions(+), 17 deletions(-)

Comments

Andrew Morton Aug. 28, 2024, 1:14 a.m. UTC | #1 
On Mon, 26 Aug 2024 12:01:29 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:

> Like isolate_lru_page(), make isolate_movable_page() as a wrapper
> around folio_isolate_movable(), since isolate_movable_page() always
> fails on a tail page, return immediately for a tail page in the warpper,
> and the wrapper will be removed once all callers are converted to
> folio_isolate_movable().
> 
> ...
>
> +bool isolate_movable_page(struct page *page, isolate_mode_t mode)
> +{
> +	if (PageTail(page))
> +		return false;
> +
> +	return folio_isolate_movable((struct folio *)page, mode);
> +}

Use page_folio() here?
Kefeng Wang Aug. 28, 2024, 6:37 a.m. UTC | #2 
On 2024/8/28 9:14, Andrew Morton wrote:
> On Mon, 26 Aug 2024 12:01:29 +0800 Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
> 
>> Like isolate_lru_page(), make isolate_movable_page() as a wrapper
>> around folio_isolate_movable(), since isolate_movable_page() always
>> fails on a tail page, return immediately for a tail page in the warpper,
>> and the wrapper will be removed once all callers are converted to
>> folio_isolate_movable().
>>
>> ...
>>
>> +bool isolate_movable_page(struct page *page, isolate_mode_t mode)
>> +{
>> +	if (PageTail(page))
>> +		return false;
>> +
>> +	return folio_isolate_movable((struct folio *)page, mode);
>> +}
> 
> Use page_folio() here?

Page must head after above check, and this function will be killed in 
patch4 , so no need to use page_folio().
diff mbox series

Patch

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 002e49b2ebd9..0a33f751596c 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -70,6 +70,7 @@  int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free,
 		  unsigned int *ret_succeeded);
 struct folio *alloc_migration_target(struct folio *src, unsigned long private);
 bool isolate_movable_page(struct page *page, isolate_mode_t mode);
+bool folio_isolate_movable(struct folio *folio, isolate_mode_t mode);
 bool isolate_folio_to_list(struct folio *folio, struct list_head *list);
 
 int migrate_huge_page_move_mapping(struct address_space *mapping,
@@ -92,6 +93,9 @@  static inline struct folio *alloc_migration_target(struct folio *src,
 	{ return NULL; }
 static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode)
 	{ return false; }
+static inline bool folio_isolate_movable(struct folio *folio,
+					 isolate_mode_t mode)
+	{ return false; }
 static inline bool isolate_folio_to_list(struct folio *folio, struct list_head *list)
 	{ return false; }
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 4f55f4930fe8..cc1c268c3822 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -58,21 +58,20 @@ 
 
 #include "internal.h"
 
-bool isolate_movable_page(struct page *page, isolate_mode_t mode)
+bool folio_isolate_movable(struct folio *folio, isolate_mode_t mode)
 {
-	struct folio *folio = folio_get_nontail_page(page);
 	const struct movable_operations *mops;
 
 	/*
-	 * Avoid burning cycles with pages that are yet under __free_pages(),
+	 * Avoid burning cycles with folios that are yet under __free_pages(),
 	 * or just got freed under us.
 	 *
-	 * In case we 'win' a race for a movable page being freed under us and
+	 * In case we 'win' a race for a movable folio being freed under us and
 	 * raise its refcount preventing __free_pages() from doing its job
-	 * the put_page() at the end of this block will take care of
-	 * release this page, thus avoiding a nasty leakage.
+	 * the folio_put() at the end of this block will take care of
+	 * release this folio, thus avoiding a nasty leakage.
 	 */
-	if (!folio)
+	if (!folio_try_get(folio))
 		goto out;
 
 	if (unlikely(folio_test_slab(folio)))
@@ -80,9 +79,9 @@  bool isolate_movable_page(struct page *page, isolate_mode_t mode)
 	/* Pairs with smp_wmb() in slab freeing, e.g. SLUB's __free_slab() */
 	smp_rmb();
 	/*
-	 * Check movable flag before taking the page lock because
-	 * we use non-atomic bitops on newly allocated page flags so
-	 * unconditionally grabbing the lock ruins page's owner side.
+	 * Check movable flag before taking the folio lock because
+	 * we use non-atomic bitops on newly allocated folio flags so
+	 * unconditionally grabbing the lock ruins folio's owner side.
 	 */
 	if (unlikely(!__folio_test_movable(folio)))
 		goto out_putfolio;
@@ -92,15 +91,15 @@  bool isolate_movable_page(struct page *page, isolate_mode_t mode)
 		goto out_putfolio;
 
 	/*
-	 * As movable pages are not isolated from LRU lists, concurrent
-	 * compaction threads can race against page migration functions
-	 * as well as race against the releasing a page.
+	 * As movable folios are not isolated from LRU lists, concurrent
+	 * compaction threads can race against folio migration functions
+	 * as well as race against the releasing a folio.
 	 *
-	 * In order to avoid having an already isolated movable page
+	 * In order to avoid having an already isolated movable folio
 	 * being (wrongly) re-isolated while it is under migration,
-	 * or to avoid attempting to isolate pages being released,
-	 * lets be sure we have the page lock
-	 * before proceeding with the movable page isolation steps.
+	 * or to avoid attempting to isolate folios being released,
+	 * lets be sure we have the folio lock
+	 * before proceeding with the movable folio isolation steps.
 	 */
 	if (unlikely(!folio_trylock(folio)))
 		goto out_putfolio;
@@ -129,6 +128,14 @@  bool isolate_movable_page(struct page *page, isolate_mode_t mode)
 	return false;
 }
 
+bool isolate_movable_page(struct page *page, isolate_mode_t mode)
+{
+	if (PageTail(page))
+		return false;
+
+	return folio_isolate_movable((struct folio *)page, mode);
+}
+
 static void putback_movable_folio(struct folio *folio)
 {
 	const struct movable_operations *mops = folio_movable_ops(folio);