The commit 4c39529663b9 adds a warning about duplicate cache names if
CONFIG_DEBUG_VM is selected. These warnings are triggered by the dm-cache
code.
The dm-cache code allocates a slab cache for each device. This commit
changes it to allocate just one slab cache in the module init function.
Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
Fixes: 4c39529663b9 ("slab: Warn on duplicate cache names when DEBUG_VM=y")
---
drivers/md/dm-cache-background-tracker.c | 25 ++++++-------------------
drivers/md/dm-cache-background-tracker.h | 8 ++++++++
drivers/md/dm-cache-target.c | 25 ++++++++++++++++++++-----
3 files changed, 34 insertions(+), 24 deletions(-)
Index: linux-2.6/drivers/md/dm-cache-background-tracker.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-cache-background-tracker.c 2023-09-05
14:45:58.000000000 +0200
+++ linux-2.6/drivers/md/dm-cache-background-tracker.c 2024-11-07
15:54:05.000000000 +0100
@@ -11,12 +11,6 @@
#define DM_MSG_PREFIX "dm-background-tracker"
-struct bt_work {
- struct list_head list;
- struct rb_node node;
- struct policy_work work;
-};
-
struct background_tracker {
unsigned int max_work;
atomic_t pending_promotes;
@@ -26,10 +20,10 @@ struct background_tracker {
struct list_head issued;
struct list_head queued;
struct rb_root pending;
-
- struct kmem_cache *work_cache;
};
+struct kmem_cache *btracker_work_cache = NULL;
+
struct background_tracker *btracker_create(unsigned int max_work)
{
struct background_tracker *b = kmalloc(sizeof(*b), GFP_KERNEL);
@@ -48,12 +42,6 @@ struct background_tracker *btracker_crea
INIT_LIST_HEAD(&b->queued);
b->pending = RB_ROOT;
- b->work_cache = KMEM_CACHE(bt_work, 0);
- if (!b->work_cache) {
- DMERR("couldn't create mempool for background work items");
- kfree(b);
- b = NULL;
- }
return b;
}
@@ -66,10 +54,9 @@ void btracker_destroy(struct background_
BUG_ON(!list_empty(&b->issued));
list_for_each_entry_safe (w, tmp, &b->queued, list) {
list_del(&w->list);
- kmem_cache_free(b->work_cache, w);
+ kmem_cache_free(btracker_work_cache, w);
}
- kmem_cache_destroy(b->work_cache);
kfree(b);
}
EXPORT_SYMBOL_GPL(btracker_destroy);
@@ -180,7 +167,7 @@ static struct bt_work *alloc_work(struct
if (max_work_reached(b))
return NULL;
- return kmem_cache_alloc(b->work_cache, GFP_NOWAIT);
+ return kmem_cache_alloc(btracker_work_cache, GFP_NOWAIT);
}
int btracker_queue(struct background_tracker *b,
@@ -203,7 +190,7 @@ int btracker_queue(struct background_tra
* There was a race, we'll just ignore this second
* bit of work for the same oblock.
*/
- kmem_cache_free(b->work_cache, w);
+ kmem_cache_free(btracker_work_cache, w);
return -EINVAL;
}
@@ -244,7 +231,7 @@ void btracker_complete(struct background
update_stats(b, &w->work, -1);
rb_erase(&w->node, &b->pending);
list_del(&w->list);
- kmem_cache_free(b->work_cache, w);
+ kmem_cache_free(btracker_work_cache, w);
}
EXPORT_SYMBOL_GPL(btracker_complete);
Index: linux-2.6/drivers/md/dm-cache-background-tracker.h
===================================================================
--- linux-2.6.orig/drivers/md/dm-cache-background-tracker.h 2023-09-05
14:45:58.000000000 +0200
+++ linux-2.6/drivers/md/dm-cache-background-tracker.h 2024-11-07
15:53:42.000000000 +0100
@@ -26,6 +26,14 @@
* protected with a spinlock.
*/
+struct bt_work {
+ struct list_head list;
+ struct rb_node node;
+ struct policy_work work;
+};
+
+extern struct kmem_cache *btracker_work_cache;
+
struct background_work;
struct background_tracker;
Index: linux-2.6/drivers/md/dm-cache-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-cache-target.c 2024-11-07 12:47:50.000000000
+0100
+++ linux-2.6/drivers/md/dm-cache-target.c 2024-11-07 15:58:34.000000000
+0100
@@ -10,6 +10,7 @@
#include "dm-bio-record.h"
#include "dm-cache-metadata.h"
#include "dm-io-tracker.h"
+#include "dm-cache-background-tracker.h"
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
@@ -2263,7 +2264,7 @@ static int parse_cache_args(struct cache
/*----------------------------------------------------------------*/
-static struct kmem_cache *migration_cache;
+static struct kmem_cache *migration_cache = NULL;
#define NOT_CORE_OPTION 1
@@ -3445,22 +3446,36 @@ static int __init dm_cache_init(void)
int r;
migration_cache = KMEM_CACHE(dm_cache_migration, 0);
- if (!migration_cache)
- return -ENOMEM;
+ if (!migration_cache) {
+ r = -ENOMEM;
+ goto err;
+ }
+
+ btracker_work_cache = kmem_cache_create("dm_cache_bt_work",
+ sizeof(struct bt_work), __alignof__(struct bt_work), 0, NULL);
+ if (!btracker_work_cache) {
+ r = -ENOMEM;
+ goto err;
+ }
r = dm_register_target(&cache_target);
if (r) {
- kmem_cache_destroy(migration_cache);
- return r;
+ goto err;
}
return 0;
+
+err:
+ kmem_cache_destroy(migration_cache);
+ kmem_cache_destroy(btracker_work_cache);
+ return r;
}
static void __exit dm_cache_exit(void)
{
dm_unregister_target(&cache_target);
kmem_cache_destroy(migration_cache);
+ kmem_cache_destroy(btracker_work_cache);
}
module_init(dm_cache_init);
