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Date: Thu, 21 Oct 2010 10:36:51 +0800
From: Gui Jianfeng <guijianfeng@...fujitsu.com>
To: Vivek Goyal <vgoyal@...hat.com>, Jens Axboe <axboe@...nel.dk>
CC: Nauman Rafique <nauman@...gle.com>,
Chad Talbott <ctalbott@...gle.com>,
Divyesh Shah <dpshah@...gle.com>,
linux kernel mailing list <linux-kernel@...r.kernel.org>,
Gui Jianfeng <guijianfeng@...fujitsu.com>
Subject: [PATCH 3/4] cfq-iosched: Enable both hierarchical mode and flat mode
for cfq group scheduling
This patch enables both hierarchical mode and flat mode for cfq group scheduling.
Users can switch between two modes by using "use_hierarchy" interface in blkio
cgroup.
Signed-off-by: Gui Jianfeng <guijianfeng@...fujitsu.com>
---
block/cfq-iosched.c | 256 +++++++++++++++++++++++++++++++++++++++------------
1 files changed, 196 insertions(+), 60 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f781e4d..98c9191 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -240,6 +240,9 @@ struct cfq_data {
/* cfq group schedule in flat or hierarchy manner. */
bool use_hierarchy;
+ /* Service tree for cfq group flat scheduling mode. */
+ struct cfq_rb_root grp_service_tree;
+
/*
* The priority currently being served
*/
@@ -635,10 +638,20 @@ static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
static inline unsigned
cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
- struct io_sched_entity *queue_entity = &cfqg->queue_se;
- struct cfq_rb_root *st = queue_entity->st;
+ struct cfq_rb_root *st;
+ unsigned int weight;
+
+ if (cfqd->use_hierarchy) {
+ struct io_sched_entity *queue_entity = &cfqg->queue_se;
+ st = queue_entity->st;
+ weight = queue_entity->weight;
+ } else {
+ struct io_sched_entity *group_entity = &cfqg->group_se;
+ st = &cfqd->grp_service_tree;
+ weight = group_entity->weight;
+ }
- return cfq_target_latency * queue_entity->weight / st->total_weight;
+ return cfq_target_latency * weight / st->total_weight;
}
static inline void
@@ -932,16 +945,30 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfqg->nr_cfqq++;
- io_sched_entity_add(queue_entity->st, queue_entity);
+ if (cfqd->use_hierarchy) {
+ io_sched_entity_add(queue_entity->st, queue_entity);
- while (group_entity && group_entity->parent) {
+ while (group_entity && group_entity->parent) {
+ if (group_entity->on_st)
+ return;
+ io_sched_entity_add(group_entity->st, group_entity);
+ group_entity = group_entity->parent;
+ __cfqg = cfqg_of_group_entity(group_entity);
+ __cfqg->nr_subgp++;
+ }
+ } else {
if (group_entity->on_st)
return;
+
+ /*
+ * For flat mode, all cfq group schedule on the global service
+ * tree(cfqd->grp_service_tree).
+ */
io_sched_entity_add(group_entity->st, group_entity);
- group_entity = group_entity->parent;
- __cfqg = cfqg_of_group_entity(group_entity);
- __cfqg->nr_subgp++;
+
}
+
+
}
static void io_sched_entity_del(struct io_sched_entity *se)
@@ -975,24 +1002,32 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
if (cfqg->nr_cfqq)
return;
- /* dequeue queue se from group */
- io_sched_entity_del(queue_entity);
+ /* For cfq group hierarchical schuduling case */
+ if (cfqd->use_hierarchy) {
+ /* dequeue queue se from group */
+ io_sched_entity_del(queue_entity);
- if (cfqg->nr_subgp)
- return;
+ if (cfqg->nr_subgp)
+ return;
- /* prevent from dequeuing root group */
- while (group_entity && group_entity->parent) {
- __cfqg = cfqg_of_group_entity(group_entity);
- p_cfqg = cfqg_of_group_entity(group_entity->parent);
+ /* prevent from dequeuing root group */
+ while (group_entity && group_entity->parent) {
+ __cfqg = cfqg_of_group_entity(group_entity);
+ p_cfqg = cfqg_of_group_entity(group_entity->parent);
+ io_sched_entity_del(group_entity);
+ cfq_blkiocg_update_dequeue_stats(&__cfqg->blkg, 1);
+ cfq_log_cfqg(cfqd, __cfqg, "del_from_rr group");
+ __cfqg->saved_workload_slice = 0;
+ group_entity = group_entity->parent;
+ p_cfqg->nr_subgp--;
+ if (p_cfqg->nr_cfqq || p_cfqg->nr_subgp)
+ return;
+ }
+ } else {
+ cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
io_sched_entity_del(group_entity);
- cfq_blkiocg_update_dequeue_stats(&__cfqg->blkg, 1);
- cfq_log_cfqg(cfqd, __cfqg, "del_from_rr group");
- __cfqg->saved_workload_slice = 0;
- group_entity = group_entity->parent;
- p_cfqg->nr_subgp--;
- if (p_cfqg->nr_cfqq || p_cfqg->nr_subgp)
- return;
+ cfqg->saved_workload_slice = 0;
+ cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
}
}
@@ -1026,7 +1061,7 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
struct cfq_queue *cfqq)
{
struct io_sched_entity *group_entity = &cfqg->group_se;
- struct io_sched_entity *queue_entity = &cfqg->queue_se;
+ struct io_sched_entity *queue_entity;
unsigned int used_sl, charge;
int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
- cfqg->service_tree_idle.count;
@@ -1039,25 +1074,33 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
else if (!cfq_cfqq_sync(cfqq) && !nr_sync)
charge = cfqq->allocated_slice;
- /*
- * update queue se's vdisktime.
- * Can't update vdisktime while group is on service tree.
- */
-
- cfq_rb_erase(&queue_entity->rb_node, queue_entity->st);
- queue_entity->vdisktime += cfq_scale_slice(charge, queue_entity);
- __io_sched_entity_add(queue_entity->st, queue_entity);
- if (&queue_entity->rb_node == queue_entity->st->active)
- queue_entity->st->active = NULL;
-
- while (group_entity && group_entity->parent) {
+ if (cfqd->use_hierarchy) {
+ /*
+ * update queue se's vdisktime.
+ * Can't update vdisktime while group is on service tree.
+ */
+ queue_entity = &cfqg->queue_se;
+ cfq_rb_erase(&queue_entity->rb_node, queue_entity->st);
+ queue_entity->vdisktime += cfq_scale_slice(charge,
+ queue_entity);
+ __io_sched_entity_add(queue_entity->st, queue_entity);
+ if (&queue_entity->rb_node == queue_entity->st->active)
+ queue_entity->st->active = NULL;
+
+ while (group_entity && group_entity->parent) {
+ cfq_rb_erase(&group_entity->rb_node, group_entity->st);
+ group_entity->vdisktime += cfq_scale_slice(charge,
+ group_entity);
+ __io_sched_entity_add(group_entity->st, group_entity);
+ if (&group_entity->rb_node == group_entity->st->active)
+ group_entity->st->active = NULL;
+ group_entity = group_entity->parent;
+ }
+ } else {
cfq_rb_erase(&group_entity->rb_node, group_entity->st);
group_entity->vdisktime += cfq_scale_slice(charge,
group_entity);
__io_sched_entity_add(group_entity->st, group_entity);
- if (&group_entity->rb_node == group_entity->st->active)
- group_entity->st->active = NULL;
- group_entity = group_entity->parent;
}
/* This group is being expired. Save the context */
@@ -1125,13 +1168,35 @@ static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfq_put_cfqg(cfqg);
}
-void
-cfq_update_blkio_use_hierarchy(struct blkio_group *blkg, bool val)
+static int cfq_forced_dispatch(struct cfq_data *cfqd);
+
+void cfq_update_blkio_use_hierarchy(struct blkio_group *blkg, bool val)
{
+ unsigned long flags;
struct cfq_group *cfqg;
+ struct cfq_data *cfqd;
+ struct io_sched_entity *group_entity;
+ int nr;
+ /* Get root group here */
cfqg = cfqg_of_blkg(blkg);
- cfqg->cfqd->use_hierarchy = val;
+ cfqd = cfqg->cfqd;
+
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+
+ /* Drain all requests */
+ nr = cfq_forced_dispatch(cfqd);
+
+ group_entity = &cfqg->group_se;
+
+ if (!val)
+ group_entity->st = &cfqd->grp_service_tree;
+ else
+ group_entity->st = NULL;
+
+ cfqd->use_hierarchy = val;
+
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
static void init_group_queue_entity(struct blkio_cgroup *blkcg,
@@ -1202,11 +1267,21 @@ static void uninit_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfq_destroy_cfqg(cfqd, cfqg);
}
-static void cfqg_set_parent(struct cfq_group *cfqg, struct cfq_group *p_cfqg)
+static void cfqg_set_parent(struct cfq_data *cfqd, struct cfq_group *cfqg,
+ struct cfq_group *p_cfqg)
{
- struct io_sched_entity *group_entity = &cfqg->group_se;
- struct io_sched_entity *queue_entity = &cfqg->queue_se;
- struct io_sched_entity *p_group_entity = &p_cfqg->group_se;
+ struct io_sched_entity *group_entity, *queue_entity, *p_group_entity;
+
+ group_entity = &cfqg->group_se;
+
+ if (!p_cfqg) {
+ group_entity->st = &cfqd->grp_service_tree;
+ group_entity->parent = NULL;
+ return;
+ }
+
+ queue_entity = &cfqg->queue_se;
+ p_group_entity = &p_cfqg->group_se;
group_entity->parent = p_group_entity;
group_entity->st = &p_cfqg->grp_service_tree;
@@ -1258,10 +1333,39 @@ int cfqg_chain_alloc(struct cfq_data *cfqd, struct cgroup *cgroup)
p_cfqg = cfqg_of_blkg(blkiocg_lookup_group(p_blkcg, key));
BUG_ON(p_cfqg == NULL);
- cfqg_set_parent(cfqg, p_cfqg);
+ cfqg_set_parent(cfqd, cfqg, p_cfqg);
return 0;
}
+static struct cfq_group *cfqg_alloc(struct cfq_data *cfqd,
+ struct cgroup *cgroup)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
+ struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
+ unsigned int major, minor;
+ struct cfq_group *cfqg;
+ void *key = cfqd;
+
+ cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ if (cfqg) {
+ if (!cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
+ sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+ cfqg->blkg.dev = MKDEV(major, minor);
+ }
+ return cfqg;
+ }
+
+ cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node);
+ if (!cfqg)
+ return NULL;
+
+ init_cfqg(cfqd, blkcg, cfqg);
+
+ cfqg_set_parent(cfqd, cfqg, NULL);
+
+ return cfqg;
+}
+
static struct cfq_group *
cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
{
@@ -1281,11 +1385,26 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
if (cfqg || !create)
goto done;
- ret = cfqg_chain_alloc(cfqd, cgroup);
- if (!ret) {
- cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
- BUG_ON(cfqg == NULL);
- goto done;
+ if (!cfqd->use_hierarchy) {
+ /*
+ * For flat cfq group scheduling, we just need to allocate a
+ * single cfq group.
+ */
+ cfqg = cfqg_alloc(cfqd, cgroup);
+ if (!cfqg)
+ goto done;
+ return cfqg;
+ } else {
+ /*
+ * For hierarchical cfq group scheduling, we need to allocate
+ * the whole cfq group chain.
+ */
+ ret = cfqg_chain_alloc(cfqd, cgroup);
+ if (!ret) {
+ cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ BUG_ON(cfqg == NULL);
+ goto done;
+ }
}
done:
return cfqg;
@@ -2404,23 +2523,37 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
{
- struct cfq_group *root_group = &cfqd->root_group;
- struct cfq_rb_root *st = &root_group->grp_service_tree;
+ struct cfq_rb_root *st;
struct cfq_group *cfqg;
struct io_sched_entity *se;
- do {
+ if (cfqd->use_hierarchy) {
+ struct cfq_group *root_group = &cfqd->root_group;
+ st = &root_group->grp_service_tree;
+
+ do {
+ se = cfq_rb_first_se(st);
+ if (!se)
+ return NULL;
+ st->active = &se->rb_node;
+ update_min_vdisktime(st);
+ cfqg = cfqg_of_queue_entity(se);
+ if (cfqg)
+ return cfqg;
+ cfqg = cfqg_of_group_entity(se);
+ st = &cfqg->grp_service_tree;
+ } while (1);
+ } else {
+ st = &cfqd->grp_service_tree;
se = cfq_rb_first_se(st);
if (!se)
return NULL;
st->active = &se->rb_node;
update_min_vdisktime(st);
- cfqg = cfqg_of_queue_entity(se);
- if (cfqg)
- return cfqg;
cfqg = cfqg_of_group_entity(se);
- st = &cfqg->grp_service_tree;
- } while (1);
+ BUG_ON(!cfqg);
+ return cfqg;
+ }
}
static void cfq_choose_cfqg(struct cfq_data *cfqd)
@@ -4089,6 +4222,9 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->cic_index = i;
+ /* Init flat service tree */
+ cfqd->grp_service_tree = CFQ_RB_ROOT;
+
/* Init root group */
cfqg = &cfqd->root_group;
cfqg->cfqd = cfqd;
-- 1.6.5.2
--
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