blkio: Implement dynamic io controlling policy registration
o One of the goals of block IO controller is that it should be able to
support mulitple io control policies, some of which be operational at
higher level in storage hierarchy.
o To begin with, we had one io controlling policy implemented by CFQ, and
I hard coded the CFQ functions called by blkio. This created issues when
CFQ is compiled as module.
o This patch implements a basic dynamic io controlling policy registration
functionality in blkio. This is similar to elevator functionality where
ioschedulers register the functions dynamically.
o Now in future, when more IO controlling policies are implemented, these
can dynakically register with block IO controller.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 7f3f343..78f4829 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -14,7 +14,6 @@
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
#include "blk-cgroup.h"
-#include "cfq-iosched.h"
/*
* tunables
@@ -3855,6 +3854,17 @@
.elevator_owner = THIS_MODULE,
};
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+static struct blkio_policy_type blkio_policy_cfq = {
+ .ops = {
+ .blkio_unlink_group_fn = cfq_unlink_blkio_group,
+ .blkio_update_group_weight_fn = cfq_update_blkio_group_weight,
+ },
+};
+#else
+static struct blkio_policy_type blkio_policy_cfq;
+#endif
+
static int __init cfq_init(void)
{
/*
@@ -3869,6 +3879,7 @@
return -ENOMEM;
elv_register(&iosched_cfq);
+ blkio_policy_register(&blkio_policy_cfq);
return 0;
}
@@ -3876,6 +3887,7 @@
static void __exit cfq_exit(void)
{
DECLARE_COMPLETION_ONSTACK(all_gone);
+ blkio_policy_unregister(&blkio_policy_cfq);
elv_unregister(&iosched_cfq);
ioc_gone = &all_gone;
/* ioc_gone's update must be visible before reading ioc_count */
