The patch titled
Subject: mm: vmscan: rework move_pages_to_lru()
has been added to the -mm mm-unstable branch. Its filename is
mm-vmscan-rework-move_pages_to_lru.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-rework-move_pages_to_lru.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: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: vmscan: rework move_pages_to_lru()
Date: Tue, 21 Jun 2022 20:56:52 +0800
In a later patch, we will reparent the LRU pages. The pages moved to
appropriate LRU list can be reparented during the process of the
move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we
should use the more general interface of folio_lruvec_relock_irq() to
acquire the correct lruvec lock.
Link: https://lkml.kernel.org/r/20220621125658.64935-6-songmuchun@xxxxxxxxxxxxx
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 39 +++++++++++++++++++--------------------
1 file changed, 19 insertions(+), 20 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-rework-move_pages_to_lru
+++ a/mm/vmscan.c
@@ -2312,23 +2312,26 @@ static int too_many_isolated(struct pgli
* move_pages_to_lru() moves folios from private @list to appropriate LRU list.
* On return, @list is reused as a list of folios to be freed by the caller.
*
- * Returns the number of pages moved to the given lruvec.
+ * Returns the number of pages moved to the appropriate LRU list.
+ *
+ * Note: The caller must not hold any lruvec lock.
*/
-static unsigned int move_pages_to_lru(struct lruvec *lruvec,
- struct list_head *list)
+static unsigned int move_pages_to_lru(struct list_head *list)
{
int nr_pages, nr_moved = 0;
+ struct lruvec *lruvec = NULL;
LIST_HEAD(folios_to_free);
while (!list_empty(list)) {
struct folio *folio = lru_to_folio(list);
+ lruvec = folio_lruvec_relock_irq(folio, lruvec);
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
list_del(&folio->lru);
if (unlikely(!folio_evictable(folio))) {
- spin_unlock_irq(&lruvec->lru_lock);
+ lruvec_unlock_irq(lruvec);
folio_putback_lru(folio);
- spin_lock_irq(&lruvec->lru_lock);
+ lruvec = NULL;
continue;
}
@@ -2349,19 +2352,15 @@ static unsigned int move_pages_to_lru(st
__folio_clear_lru_flags(folio);
if (unlikely(folio_test_large(folio))) {
- spin_unlock_irq(&lruvec->lru_lock);
+ lruvec_unlock_irq(lruvec);
destroy_large_folio(folio);
- spin_lock_irq(&lruvec->lru_lock);
+ lruvec = NULL;
} else
list_add(&folio->lru, &folios_to_free);
continue;
}
- /*
- * All pages were isolated from the same lruvec (and isolation
- * inhibits memcg migration).
- */
VM_BUG_ON_FOLIO(!folio_matches_lruvec(folio, lruvec), folio);
lruvec_add_folio(lruvec, folio);
nr_pages = folio_nr_pages(folio);
@@ -2370,6 +2369,8 @@ static unsigned int move_pages_to_lru(st
workingset_age_nonresident(lruvec, nr_pages);
}
+ if (lruvec)
+ lruvec_unlock_irq(lruvec);
/*
* To save our caller's stack, now use input list for pages to free.
*/
@@ -2440,16 +2441,16 @@ shrink_inactive_list(unsigned long nr_to
nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false);
- spin_lock_irq(&lruvec->lru_lock);
- move_pages_to_lru(lruvec, &page_list);
+ move_pages_to_lru(&page_list);
+ local_irq_disable();
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
if (!cgroup_reclaim(sc))
__count_vm_events(item, nr_reclaimed);
__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
__count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
- spin_unlock_irq(&lruvec->lru_lock);
+ local_irq_enable();
lru_note_cost(lruvec, file, stat.nr_pageout);
mem_cgroup_uncharge_list(&page_list);
@@ -2578,18 +2579,16 @@ static void shrink_active_list(unsigned
/*
* Move folios back to the lru list.
*/
- spin_lock_irq(&lruvec->lru_lock);
-
- nr_activate = move_pages_to_lru(lruvec, &l_active);
- nr_deactivate = move_pages_to_lru(lruvec, &l_inactive);
+ nr_activate = move_pages_to_lru(&l_active);
+ nr_deactivate = move_pages_to_lru(&l_inactive);
/* Keep all free folios in l_active list */
list_splice(&l_inactive, &l_active);
+ local_irq_disable();
__count_vm_events(PGDEACTIVATE, nr_deactivate);
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
-
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
- spin_unlock_irq(&lruvec->lru_lock);
+ local_irq_enable();
mem_cgroup_uncharge_list(&l_active);
free_unref_page_list(&l_active);
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-memory_hotplug-enumerate-all-supported-section-flags.patch
mm-memory_hotplug-make-hugetlb_optimize_vmemmap-compatible-with-memmap_on_memory.patch
mm-hugetlb-remove-minimum_order-variable.patch
mm-memcontrol-remove-dead-code-and-comments.patch
mm-rename-unlock_page_lruvec_irq-_irqrestore-to-lruvec_unlock_irq-_irqrestore.patch
mm-memcontrol-prepare-objcg-api-for-non-kmem-usage.patch
mm-memcontrol-make-lruvec-lock-safe-when-lru-pages-are-reparented.patch
mm-vmscan-rework-move_pages_to_lru.patch
mm-thp-make-split-queue-lock-safe-when-lru-pages-are-reparented.patch
mm-memcontrol-make-all-the-callers-of-foliopage_memcg-safe.patch
mm-memcontrol-introduce-memcg_reparent_ops.patch
mm-memcontrol-use-obj_cgroup-apis-to-charge-the-lru-pages.patch
mm-lru-add-vm_warn_on_once_folio-to-lru-maintenance-function.patch
mm-lru-use-lruvec-lock-to-serialize-memcg-changes.patch
