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.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");