dm: add reserved_bio_based_ios module parameter
Allow user to change the number of IOs that are reserved by
bio-based DM's mempools by writing to this file:
/sys/module/dm_mod/parameters/reserved_bio_based_ios
The default value is RESERVED_BIO_BASED_IOS (16). The maximum allowed
value is RESERVED_MAX_IOS (1024).
Export dm_get_reserved_bio_based_ios() for use by DM targets and core
code. Switch to sizing dm-io's mempool and bioset using DM core's
configurable 'reserved_bio_based_ios'.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Frank Mayhar <fmayhar@google.com>
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ea49834..2a20986 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -19,8 +19,6 @@
#define DM_MSG_PREFIX "io"
#define DM_IO_MAX_REGIONS BITS_PER_LONG
-#define MIN_IOS 16
-#define MIN_BIOS 16
struct dm_io_client {
mempool_t *pool;
@@ -50,16 +48,17 @@
struct dm_io_client *dm_io_client_create(void)
{
struct dm_io_client *client;
+ unsigned min_ios = dm_get_reserved_bio_based_ios();
client = kmalloc(sizeof(*client), GFP_KERNEL);
if (!client)
return ERR_PTR(-ENOMEM);
- client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);
+ client->pool = mempool_create_slab_pool(min_ios, _dm_io_cache);
if (!client->pool)
goto bad;
- client->bios = bioset_create(MIN_BIOS, 0);
+ client->bios = bioset_create(min_ios, 0);
if (!client->bios)
goto bad;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 1e85f1d..b3e26c7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -218,6 +218,11 @@
static struct kmem_cache *_rq_tio_cache;
/*
+ * Bio-based DM's mempools' reserved IOs set by the user.
+ */
+static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
+
+/*
* Request-based DM's mempools' reserved IOs set by the user.
*/
static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
@@ -241,6 +246,13 @@
return ios;
}
+unsigned dm_get_reserved_bio_based_ios(void)
+{
+ return __dm_get_reserved_ios(&reserved_bio_based_ios,
+ RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
+}
+EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
+
unsigned dm_get_reserved_rq_based_ios(void)
{
return __dm_get_reserved_ios(&reserved_rq_based_ios,
@@ -2906,7 +2918,7 @@
if (type == DM_TYPE_BIO_BASED) {
cachep = _io_cache;
- pool_size = RESERVED_BIO_BASED_IOS;
+ pool_size = dm_get_reserved_bio_based_ios();
front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
} else if (type == DM_TYPE_REQUEST_BASED) {
cachep = _rq_tio_cache;
@@ -2969,6 +2981,9 @@
module_param(major, uint, 0);
MODULE_PARM_DESC(major, "The major number of the device mapper");
+module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
+
module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 1539650..1d1ad7b 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -184,6 +184,7 @@
/*
* Helpers that are used by DM core
*/
+unsigned dm_get_reserved_bio_based_ios(void);
unsigned dm_get_reserved_rq_based_ios(void);
static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)