The patch titled
Subject: mm: migrate: add folio_isolate_movable()
has been added to the -mm mm-unstable branch. Its filename is
mm-migrate-add-folio_isolate_movable.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migrate-add-folio_isolate_movable.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: migrate: add folio_isolate_movable()
Date: Thu, 29 Aug 2024 22:54:53 +0800
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().
Note all isolate_movable_page() users increased page reference, so replace
redundant folio_get_nontail_page() with folio_get() and add a reference
count check into folio_isolate_movable().
Link: https://lkml.kernel.org/r/20240829145456.2591719-3-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/migrate.h | 4 ++
mm/migrate.c | 54 +++++++++++++++++++++-----------------
2 files changed, 34 insertions(+), 24 deletions(-)
--- a/include/linux/migrate.h~mm-migrate-add-folio_isolate_movable
+++ a/include/linux/migrate.h
@@ -70,6 +70,7 @@ int migrate_pages(struct list_head *l, n
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_migrat
{ 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; }
--- a/mm/migrate.c~mm-migrate-add-folio_isolate_movable
+++ a/mm/migrate.c
@@ -58,31 +58,30 @@
#include "internal.h"
-bool isolate_movable_page(struct page *page, isolate_mode_t mode)
+/**
+ * folio_isolate_movable() - Try to isolate a non-lru movable folio.
+ * @folio: Folio to isolate.
+ *
+ * Must be called with an elevated refcount on the folio.
+ *
+ * Return: true if the folio was isolated, false otherwise
+ */
+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(),
- * or just got freed under us.
- *
- * In case we 'win' a race for a movable page 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.
- */
- if (!folio)
- goto out;
+ VM_BUG_ON_FOLIO(!folio_ref_count(folio), folio);
+
+ folio_get(folio);
if (unlikely(folio_test_slab(folio)))
goto out_putfolio;
/* 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 *p
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;
@@ -125,10 +124,17 @@ out_no_isolated:
folio_unlock(folio);
out_putfolio:
folio_put(folio);
-out:
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);
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-hugetlb-remove-left-over-comment-about-follow_huge_foo.patch
mm-remove-migration-for-hugepage-in-isolate_single_pageblock.patch
mm-support-only-one-page_type-per-page-fix.patch
mm-memory_hotplug-remove-head-variable-in-do_migrate_range.patch
mm-memory-failure-add-unmap_poisoned_folio.patch
mm-memory_hotplug-check-hwpoisoned-page-firstly-in-do_migrate_range.patch
mm-migrate-add-isolate_folio_to_list.patch
mm-memory_hotplug-unify-huge-lru-non-lru-movable-folio-isolation.patch
mm-memory_hotplug-unify-huge-lru-non-lru-movable-folio-isolation-fix.patch
mm-migrate_device-convert-to-migrate_device_coherent_folio.patch
mm-migrate_device-use-a-folio-in-migrate_device_range.patch
mm-migrate_device-use-more-folio-in-migrate_device_unmap.patch
mm-migrate_device-use-more-folio-in-migrate_device_finalize.patch
mm-remove-isolate_lru_page.patch
mm-remove-isolate_lru_page-fix.patch
mm-remove-putback_lru_page.patch
mm-compaction-get-reference-before-non-lru-movable-folio-isolation.patch
mm-migrate-add-folio_isolate_movable.patch
mm-migrate-convert-to-folio_isolate_movable.patch
mm-compaction-convert-to-folio_isolate_movable.patch
mm-migrate-remove-isolate_movable_page.patch
