dm: add reserved_rq_based_ios module parameter
Allow user to change the number of IOs that are reserved by
request-based DM's mempools by writing to this file:
/sys/module/dm_mod/parameters/reserved_rq_based_ios
The default value is RESERVED_REQUEST_BASED_IOS (256). The maximum
allowed value is RESERVED_MAX_IOS (1024).
Export dm_get_reserved_rq_based_ios() for use by DM targets and core
code. Switch to sizing dm-mpath's mempool using DM core's configurable
'reserved_rq_based_ios'.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index e08be94..de570a5 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -7,6 +7,7 @@
#include <linux/device-mapper.h>
+#include "dm.h"
#include "dm-path-selector.h"
#include "dm-uevent.h"
@@ -116,8 +117,6 @@
typedef int (*action_fn) (struct pgpath *pgpath);
-#define MIN_IOS 256 /* Mempool size */
-
static struct kmem_cache *_mpio_cache;
static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
@@ -190,6 +189,7 @@
static struct multipath *alloc_multipath(struct dm_target *ti)
{
struct multipath *m;
+ unsigned min_ios = dm_get_reserved_rq_based_ios();
m = kzalloc(sizeof(*m), GFP_KERNEL);
if (m) {
@@ -202,7 +202,7 @@
INIT_WORK(&m->trigger_event, trigger_event);
init_waitqueue_head(&m->pg_init_wait);
mutex_init(&m->work_mutex);
- m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
+ m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
return NULL;