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mm/slub: convert object_map_lock to non-raw spinlock 

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>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
This commit is contained in:
Vlastimil Babka 2022-08-23 19:03:59 +02:00
parent 41bec7c33f
commit 4ef3f5a320
1 changed files with 6 additions and 30 deletions
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36
mm/slub.c
View File

@ -565,7 +565,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
#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)
@ -4368,21 +4344,21 @@ static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
{
#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
}