| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20250415024532.26632-7-songmuchun@bytedance.com>
Date: Tue, 15 Apr 2025 10:45:10 +0800
From: Muchun Song <songmuchun@...edance.com>
To: hannes@...xchg.org,
mhocko@...nel.org,
roman.gushchin@...ux.dev,
shakeel.butt@...ux.dev,
muchun.song@...ux.dev,
akpm@...ux-foundation.org,
david@...morbit.com,
zhengqi.arch@...edance.com,
yosry.ahmed@...ux.dev,
nphamcs@...il.com,
chengming.zhou@...ux.dev
Cc: linux-kernel@...r.kernel.org,
cgroups@...r.kernel.org,
linux-mm@...ck.org,
hamzamahfooz@...ux.microsoft.com,
apais@...ux.microsoft.com,
Muchun Song <songmuchun@...edance.com>
Subject: [PATCH RFC 06/28] mm: thp: introduce folio_split_queue_lock and its variants
In future memcg removal, the binding between a folio and a memcg may change,
making the split lock within the memcg unstable when held.
A new approach is required to reparent the split queue to its parent. This
patch starts introducing a unified way to acquire the split lock for future
work.
It's a code-only refactoring with no functional changes.
Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
include/linux/memcontrol.h | 10 ++++
mm/huge_memory.c | 100 +++++++++++++++++++++++++++----------
2 files changed, 83 insertions(+), 27 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a045819bcf40..bb4f203733f3 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1639,6 +1639,11 @@ int alloc_shrinker_info(struct mem_cgroup *memcg);
void free_shrinker_info(struct mem_cgroup *memcg);
void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id);
void reparent_shrinker_deferred(struct mem_cgroup *memcg);
+
+static inline int shrinker_id(struct shrinker *shrinker)
+{
+ return shrinker->id;
+}
#else
#define mem_cgroup_sockets_enabled 0
static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
@@ -1652,6 +1657,11 @@ static inline void set_shrinker_bit(struct mem_cgroup *memcg,
int nid, int shrinker_id)
{
}
+
+static inline int shrinker_id(struct shrinker *shrinker)
+{
+ return -1;
+}
#endif
#ifdef CONFIG_MEMCG
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a81e89987ca2..70820fa75c1f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1059,26 +1059,75 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
#ifdef CONFIG_MEMCG
static inline
-struct deferred_split *get_deferred_split_queue(struct folio *folio)
+struct mem_cgroup *folio_split_queue_memcg(struct folio *folio,
+ struct deferred_split *queue)
+{
+ if (mem_cgroup_disabled())
+ return NULL;
+ if (&NODE_DATA(folio_nid(folio))->deferred_split_queue == queue)
+ return NULL;
+ return container_of(queue, struct mem_cgroup, deferred_split_queue);
+}
+
+static inline struct deferred_split *folio_memcg_split_queue(struct folio *folio)
{
struct mem_cgroup *memcg = folio_memcg(folio);
- struct pglist_data *pgdat = NODE_DATA(folio_nid(folio));
- if (memcg)
- return &memcg->deferred_split_queue;
- else
- return &pgdat->deferred_split_queue;
+ return memcg ? &memcg->deferred_split_queue : NULL;
}
#else
static inline
-struct deferred_split *get_deferred_split_queue(struct folio *folio)
+struct mem_cgroup *folio_split_queue_memcg(struct folio *folio,
+ struct deferred_split *queue)
{
- struct pglist_data *pgdat = NODE_DATA(folio_nid(folio));
+ return NULL;
+}
- return &pgdat->deferred_split_queue;
+static inline struct deferred_split *folio_memcg_split_queue(struct folio *folio)
+{
+ return NULL;
}
#endif
+static struct deferred_split *folio_split_queue(struct folio *folio)
+{
+ struct deferred_split *queue = folio_memcg_split_queue(folio);
+
+ return queue ? : &NODE_DATA(folio_nid(folio))->deferred_split_queue;
+}
+
+static struct deferred_split *folio_split_queue_lock(struct folio *folio)
+{
+ struct deferred_split *queue;
+
+ queue = folio_split_queue(folio);
+ spin_lock(&queue->split_queue_lock);
+
+ return queue;
+}
+
+static struct deferred_split *
+folio_split_queue_lock_irqsave(struct folio *folio, unsigned long *flags)
+{
+ struct deferred_split *queue;
+
+ queue = folio_split_queue(folio);
+ spin_lock_irqsave(&queue->split_queue_lock, *flags);
+
+ return queue;
+}
+
+static inline void split_queue_unlock(struct deferred_split *queue)
+{
+ spin_unlock(&queue->split_queue_lock);
+}
+
+static inline void split_queue_unlock_irqrestore(struct deferred_split *queue,
+ unsigned long flags)
+{
+ spin_unlock_irqrestore(&queue->split_queue_lock, flags);
+}
+
static inline bool is_transparent_hugepage(const struct folio *folio)
{
if (!folio_test_large(folio))
@@ -3723,7 +3772,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
struct page *split_at, struct page *lock_at,
struct list_head *list, bool uniform_split)
{
- struct deferred_split *ds_queue = get_deferred_split_queue(folio);
+ struct deferred_split *ds_queue;
XA_STATE(xas, &folio->mapping->i_pages, folio->index);
bool is_anon = folio_test_anon(folio);
struct address_space *mapping = NULL;
@@ -3857,7 +3906,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
}
/* Prevent deferred_split_scan() touching ->_refcount */
- spin_lock(&ds_queue->split_queue_lock);
+ ds_queue = folio_split_queue_lock(folio);
if (folio_ref_freeze(folio, 1 + extra_pins)) {
if (folio_order(folio) > 1 &&
!list_empty(&folio->_deferred_list)) {
@@ -3875,7 +3924,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
*/
list_del_init(&folio->_deferred_list);
}
- spin_unlock(&ds_queue->split_queue_lock);
+ split_queue_unlock(ds_queue);
if (mapping) {
int nr = folio_nr_pages(folio);
@@ -3896,7 +3945,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
split_at, lock_at, list, end, &xas, mapping,
uniform_split);
} else {
- spin_unlock(&ds_queue->split_queue_lock);
+ split_queue_unlock(ds_queue);
fail:
if (mapping)
xas_unlock(&xas);
@@ -4050,8 +4099,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio)
WARN_ON_ONCE(folio_ref_count(folio));
WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg_charged(folio));
- ds_queue = get_deferred_split_queue(folio);
- spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
+ ds_queue = folio_split_queue_lock_irqsave(folio, &flags);
if (!list_empty(&folio->_deferred_list)) {
ds_queue->split_queue_len--;
if (folio_test_partially_mapped(folio)) {
@@ -4062,7 +4110,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio)
list_del_init(&folio->_deferred_list);
unqueued = true;
}
- spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+ split_queue_unlock_irqrestore(ds_queue, flags);
return unqueued; /* useful for debug warnings */
}
@@ -4070,10 +4118,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio)
/* partially_mapped=false won't clear PG_partially_mapped folio flag */
void deferred_split_folio(struct folio *folio, bool partially_mapped)
{
- struct deferred_split *ds_queue = get_deferred_split_queue(folio);
-#ifdef CONFIG_MEMCG
- struct mem_cgroup *memcg = folio_memcg(folio);
-#endif
+ struct deferred_split *ds_queue;
unsigned long flags;
/*
@@ -4096,7 +4141,7 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped)
if (folio_test_swapcache(folio))
return;
- spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
+ ds_queue = folio_split_queue_lock_irqsave(folio, &flags);
if (partially_mapped) {
if (!folio_test_partially_mapped(folio)) {
folio_set_partially_mapped(folio);
@@ -4111,15 +4156,16 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped)
VM_WARN_ON_FOLIO(folio_test_partially_mapped(folio), folio);
}
if (list_empty(&folio->_deferred_list)) {
+ struct mem_cgroup *memcg;
+
+ memcg = folio_split_queue_memcg(folio, ds_queue);
list_add_tail(&folio->_deferred_list, &ds_queue->split_queue);
ds_queue->split_queue_len++;
-#ifdef CONFIG_MEMCG
if (memcg)
set_shrinker_bit(memcg, folio_nid(folio),
- deferred_split_shrinker->id);
-#endif
+ shrinker_id(deferred_split_shrinker));
}
- spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+ split_queue_unlock_irqrestore(ds_queue, flags);
}
static unsigned long deferred_split_count(struct shrinker *shrink,
@@ -4202,7 +4248,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
if (!--sc->nr_to_scan)
break;
}
- spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+ split_queue_unlock_irqrestore(ds_queue, flags);
list_for_each_entry_safe(folio, next, &list, _deferred_list) {
bool did_split = false;
@@ -4251,7 +4297,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
list_splice_tail(&list, &ds_queue->split_queue);
ds_queue->split_queue_len -= removed;
- spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+ split_queue_unlock_irqrestore(ds_queue, flags);
if (prev)
folio_put(prev);
--
2.20.1
Powered by blists - more mailing lists