1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
From: Vlastimil Babka <vbabka@suse.cz>
Date: Tue, 23 Aug 2022 19:03:59 +0200
Subject: [PATCH 4/5] mm/slub: convert object_map_lock to non-raw spinlock
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.0/older/patches-6.0.5-rt14.tar.xz
The only remaining user of object_map_lock is list_slab_objects().
Obtaining the lock there used to happen under slab_lock() which implied
disabling irqs on PREEMPT_RT, thus it's a raw_spinlock. With the
slab_lock() removed, we can convert it to a normal spinlock.
Also remove the get_map()/put_map() wrappers as list_slab_objects()
became their only remaining user.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
mm/slub.c | 36 ++++++------------------------------
1 file changed, 6 insertions(+), 30 deletions(-)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -565,7 +565,7 @@ static inline bool cmpxchg_double_slab(s
#ifdef CONFIG_SLUB_DEBUG
static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
-static DEFINE_RAW_SPINLOCK(object_map_lock);
+static DEFINE_SPINLOCK(object_map_lock);
static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
struct slab *slab)
@@ -599,30 +599,6 @@ static bool slab_add_kunit_errors(void)
static inline bool slab_add_kunit_errors(void) { return false; }
#endif
-/*
- * Determine a map of objects in use in a slab.
- *
- * Node listlock must be held to guarantee that the slab does
- * not vanish from under us.
- */
-static unsigned long *get_map(struct kmem_cache *s, struct slab *slab)
- __acquires(&object_map_lock)
-{
- VM_BUG_ON(!irqs_disabled());
-
- raw_spin_lock(&object_map_lock);
-
- __fill_map(object_map, s, slab);
-
- return object_map;
-}
-
-static void put_map(unsigned long *map) __releases(&object_map_lock)
-{
- VM_BUG_ON(map != object_map);
- raw_spin_unlock(&object_map_lock);
-}
-
static inline unsigned int size_from_object(struct kmem_cache *s)
{
if (s->flags & SLAB_RED_ZONE)
@@ -4367,21 +4343,21 @@ static void list_slab_objects(struct kme
{
#ifdef CONFIG_SLUB_DEBUG
void *addr = slab_address(slab);
- unsigned long flags;
- unsigned long *map;
void *p;
slab_err(s, slab, text, s->name);
- map = get_map(s, slab);
+ spin_lock(&object_map_lock);
+ __fill_map(object_map, s, slab);
+
for_each_object(p, s, addr, slab->objects) {
- if (!test_bit(__obj_to_index(s, addr, p), map)) {
+ if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
print_tracking(s, p);
}
}
- put_map(map);
+ spin_unlock(&object_map_lock);
#endif
}
|
