[PATCH 20/28] io-controller: noop changes for hierarchical fair queuing

From: Vivek Goyal
Date: Thu Sep 24 2009 - 15:32:26 EST


This patch changes noop to use queue scheduling code from elevator layer.
One can go back to old noop by deselecting CONFIG_IOSCHED_NOOP_HIER.

Signed-off-by: Nauman Rafique <nauman@xxxxxxxxxx>
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
---
block/Kconfig.iosched | 11 +++++++++++
block/noop-iosched.c | 14 ++++++++++++++
2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index a7d0bf8..28cd500 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -25,6 +25,17 @@ config IOSCHED_NOOP
that do their own scheduling and require only minimal assistance from
the kernel.

+config IOSCHED_NOOP_HIER
+ bool "Noop Hierarchical Scheduling support"
+ depends on IOSCHED_NOOP && CGROUPS
+ select ELV_FAIR_QUEUING
+ select GROUP_IOSCHED
+ default n
+ ---help---
+ Enable hierarhical scheduling in noop. In this mode noop keeps
+ one IO queue per cgroup instead of a global queue. Elevator
+ fair queuing logic ensures fairness among various queues.
+
config IOSCHED_AS
tristate "Anticipatory I/O scheduler"
default y
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
index 731dbf2..4ba496f 100644
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -6,6 +6,7 @@
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/init.h>
+#include "elevator-fq.h"

struct noop_queue {
struct list_head queue;
@@ -82,6 +83,15 @@ static void noop_free_noop_queue(struct elevator_queue *e, void *sched_queue)
kfree(nq);
}

+#ifdef CONFIG_IOSCHED_NOOP_HIER
+static struct elv_fs_entry noop_attrs[] = {
+ ELV_ATTR(fairness),
+ ELV_ATTR(slice_sync),
+ ELV_ATTR(group_idle),
+ __ATTR_NULL
+};
+#endif
+
static struct elevator_type elevator_noop = {
.ops = {
.elevator_merge_req_fn = noop_merged_requests,
@@ -92,6 +102,10 @@ static struct elevator_type elevator_noop = {
.elevator_alloc_sched_queue_fn = noop_alloc_noop_queue,
.elevator_free_sched_queue_fn = noop_free_noop_queue,
},
+#ifdef CONFIG_IOSCHED_NOOP_HIER
+ .elevator_features = ELV_IOSCHED_NEED_FQ | ELV_IOSCHED_SINGLE_IOQ,
+ .elevator_attrs = noop_attrs,
+#endif
.elevator_name = "noop",
.elevator_owner = THIS_MODULE,
};
--
1.6.0.6

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