[PATCH 04/10] block, cfq: reorganize cfq_io_context into generic and cfq specific parts

From: Tejun Heo
Date: Sat Oct 29 2011 - 19:51:45 EST

Currently io_context and cfq logics are mixed without clear boundary.
Most of io_context is independent from cfq but cfq_io_context handling
logic is dispersed between generic ioc code and cfq.

cfq_io_context represents association between an io_context and a
request_queue, which is a concept useful outside of cfq, but it also
contains fields which are useful only to cfq.

This patch takes out generic part and put it into io_cq (io
context-queue) and the rest into cfq_io_cq (cic moniker remains the
same) which contains io_cq. The following changes are made together.

* cfq_ttime and cfq_io_cq now live in cfq-iosched.c.

* All related fields, functions and constants are renamed accordingly.

* ioc->ioc_data is now "struct io_cq *" instead of "void *" and
renamed to icq_hint.

This prepares for io_context API cleanup. Documentation is currently
sparse. It will be added later.

Changes in this patch are mechanical and don't cause functional
change.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
---
block/blk-ioc.c | 58 +++++------
block/cfq-iosched.c | 248 ++++++++++++++++++++++++---------------------
include/linux/iocontext.h | 43 +++-----
3 files changed, 175 insertions(+), 174 deletions(-)

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index e23c797..dc5e69d 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -46,7 +46,7 @@ EXPORT_SYMBOL(get_io_context);

/*
* Slow path for ioc release in put_io_context(). Performs double-lock
- * dancing to unlink all cic's and then frees ioc.
+ * dancing to unlink all icq's and then frees ioc.
*/
static void ioc_release_fn(struct work_struct *work)
{
@@ -56,11 +56,10 @@ static void ioc_release_fn(struct work_struct *work)

spin_lock_irq(&ioc->lock);

- while (!hlist_empty(&ioc->cic_list)) {
- struct cfq_io_context *cic = hlist_entry(ioc->cic_list.first,
- struct cfq_io_context,
- cic_list);
- struct request_queue *this_q = cic->q;
+ while (!hlist_empty(&ioc->icq_list)) {
+ struct io_cq *icq = hlist_entry(ioc->icq_list.first,
+ struct io_cq, ioc_node);
+ struct request_queue *this_q = icq->q;

if (this_q != last_q) {
/*
@@ -89,8 +88,8 @@ static void ioc_release_fn(struct work_struct *work)
continue;
}
ioc_release_depth_inc(this_q);
- cic->exit(cic);
- cic->release(cic);
+ icq->exit(icq);
+ icq->release(icq);
ioc_release_depth_dec(this_q);
}

@@ -131,10 +130,10 @@ void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
return;

/*
- * Destroy @ioc. This is a bit messy because cic's are chained
+ * Destroy @ioc. This is a bit messy because icq's are chained
* from both ioc and queue, and ioc->lock nests inside queue_lock.
- * The inner ioc->lock should be held to walk our cic_list and then
- * for each cic the outer matching queue_lock should be grabbed.
+ * The inner ioc->lock should be held to walk our icq_list and then
+ * for each icq the outer matching queue_lock should be grabbed.
* ie. We need to do reverse-order double lock dancing.
*
* Another twist is that we are often called with one of the
@@ -153,11 +152,10 @@ void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
spin_lock_irqsave_nested(&ioc->lock, flags,
ioc_release_depth(locked_q));

- while (!hlist_empty(&ioc->cic_list)) {
- struct cfq_io_context *cic = hlist_entry(ioc->cic_list.first,
- struct cfq_io_context,
- cic_list);
- struct request_queue *this_q = cic->q;
+ while (!hlist_empty(&ioc->icq_list)) {
+ struct io_cq *icq = hlist_entry(ioc->icq_list.first,
+ struct io_cq, ioc_node);
+ struct request_queue *this_q = icq->q;

if (this_q != last_q) {
if (last_q && last_q != locked_q)
@@ -170,8 +168,8 @@ void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
continue;
}
ioc_release_depth_inc(this_q);
- cic->exit(cic);
- cic->release(cic);
+ icq->exit(icq);
+ icq->release(icq);
ioc_release_depth_dec(this_q);
}

@@ -180,8 +178,8 @@ void put_io_context(struct io_context *ioc, struct request_queue *locked_q)

spin_unlock_irqrestore(&ioc->lock, flags);

- /* if no cic's left, we're done; otherwise, kick release_work */
- if (hlist_empty(&ioc->cic_list))
+ /* if no icq is left, we're done; otherwise, kick release_work */
+ if (hlist_empty(&ioc->icq_list))
kmem_cache_free(iocontext_cachep, ioc);
else
schedule_work(&ioc->release_work);
@@ -219,8 +217,8 @@ void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
atomic_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1);
spin_lock_init(&ioc->lock);
- INIT_RADIX_TREE(&ioc->radix_root, GFP_ATOMIC | __GFP_HIGH);
- INIT_HLIST_HEAD(&ioc->cic_list);
+ INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
+ INIT_HLIST_HEAD(&ioc->icq_list);
INIT_WORK(&ioc->release_work, ioc_release_fn);

/* try to install, somebody might already have beaten us to it */
@@ -270,11 +268,11 @@ EXPORT_SYMBOL(get_task_io_context);

void ioc_set_changed(struct io_context *ioc, int which)
{
- struct cfq_io_context *cic;
+ struct io_cq *icq;
struct hlist_node *n;

- hlist_for_each_entry(cic, n, &ioc->cic_list, cic_list)
- set_bit(which, &cic->changed);
+ hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
+ set_bit(which, &icq->changed);
}

/**
@@ -282,8 +280,8 @@ void ioc_set_changed(struct io_context *ioc, int which)
* @ioc: io_context of interest
* @ioprio: new ioprio
*
- * @ioc's ioprio has changed to @ioprio. Set %CIC_IOPRIO_CHANGED for all
- * cic's. iosched is responsible for checking the bit and applying it on
+ * @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
+ * icq's. iosched is responsible for checking the bit and applying it on
* request issue path.
*/
void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
@@ -292,7 +290,7 @@ void ioc_ioprio_changed(struct io_context *ioc, int ioprio)

spin_lock_irqsave(&ioc->lock, flags);
ioc->ioprio = ioprio;
- ioc_set_changed(ioc, CIC_IOPRIO_CHANGED);
+ ioc_set_changed(ioc, ICQ_IOPRIO_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}

@@ -300,7 +298,7 @@ void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
* ioc_cgroup_changed - notify cgroup change
* @ioc: io_context of interest
*
- * @ioc's cgroup has changed. Set %CIC_CGROUP_CHANGED for all cic's.
+ * @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
* iosched is responsible for checking the bit and applying it on request
* issue path.
*/
@@ -309,7 +307,7 @@ void ioc_cgroup_changed(struct io_context *ioc)
unsigned long flags;

spin_lock_irqsave(&ioc->lock, flags);
- ioc_set_changed(ioc, CIC_CGROUP_CHANGED);
+ ioc_set_changed(ioc, ICQ_CGROUP_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 5f7e4d1..d2f16fc 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -54,13 +54,12 @@ static const int cfq_hist_divisor = 4;
#define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32)
#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)

-#define RQ_CIC(rq) \
- ((struct cfq_io_context *) (rq)->elevator_private[0])
+#define RQ_CIC(rq) icq_to_cic((rq)->elevator_private[0])
#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1])
#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2])

static struct kmem_cache *cfq_pool;
-static struct kmem_cache *cfq_ioc_pool;
+static struct kmem_cache *cfq_icq_pool;

#define CFQ_PRIO_LISTS IOPRIO_BE_NR
#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
@@ -69,6 +68,14 @@ static struct kmem_cache *cfq_ioc_pool;
#define sample_valid(samples) ((samples) > 80)
#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node)

+struct cfq_ttime {
+ unsigned long last_end_request;
+
+ unsigned long ttime_total;
+ unsigned long ttime_samples;
+ unsigned long ttime_mean;
+};
+
/*
* Most of our rbtree usage is for sorting with min extraction, so
* if we cache the leftmost node we don't have to walk down the tree
@@ -210,6 +217,12 @@ struct cfq_group {
struct cfq_ttime ttime;
};

+struct cfq_io_cq {
+ struct io_cq icq; /* must be the first member */
+ struct cfq_queue *cfqq[2];
+ struct cfq_ttime ttime;
+};
+
/*
* Per block device queue structure
*/
@@ -261,7 +274,7 @@ struct cfq_data {
struct work_struct unplug_work;

struct cfq_queue *active_queue;
- struct cfq_io_context *active_cic;
+ struct cfq_io_cq *active_cic;

/*
* async queue for each priority case
@@ -284,7 +297,7 @@ struct cfq_data {
unsigned int cfq_group_idle;
unsigned int cfq_latency;

- struct list_head cic_list;
+ struct list_head icq_list;

/*
* Fallback dummy cfqq for extreme OOM conditions
@@ -457,24 +470,28 @@ static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
static void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
struct io_context *, gfp_t);
-static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
- struct io_context *);
+static struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *, struct io_context *);

-static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
- bool is_sync)
+static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
+{
+ /* cic->icq is the first member, %NULL will convert to %NULL */
+ return container_of(icq, struct cfq_io_cq, icq);
+}
+
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync)
{
return cic->cfqq[is_sync];
}

-static inline void cic_set_cfqq(struct cfq_io_context *cic,
- struct cfq_queue *cfqq, bool is_sync)
+static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
+ bool is_sync)
{
cic->cfqq[is_sync] = cfqq;
}

-static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic)
+static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic)
{
- return cic->q->elevator->elevator_data;
+ return cic->icq.q->elevator->elevator_data;
}

/*
@@ -1541,7 +1558,7 @@ static struct request *
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;

cic = cfq_cic_lookup(cfqd, tsk->io_context);
@@ -1655,7 +1672,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;

/*
@@ -1671,7 +1688,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
* and %current are guaranteed to be equal. Avoid lookup which
* requires queue_lock by using @rq's cic.
*/
- if (current->io_context == RQ_CIC(rq)->ioc) {
+ if (current->io_context == RQ_CIC(rq)->icq.ioc) {
cic = RQ_CIC(rq);
} else {
cic = cfq_cic_lookup(cfqd, current->io_context);
@@ -1761,7 +1778,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqd->active_queue = NULL;

if (cfqd->active_cic) {
- put_io_context(cfqd->active_cic->ioc, cfqd->queue);
+ put_io_context(cfqd->active_cic->icq.ioc, cfqd->queue);
cfqd->active_cic = NULL;
}
}
@@ -1981,7 +1998,7 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
static void cfq_arm_slice_timer(struct cfq_data *cfqd)
{
struct cfq_queue *cfqq = cfqd->active_queue;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
unsigned long sl, group_idle = 0;

/*
@@ -2016,7 +2033,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
* task has exited, don't wait
*/
cic = cfqd->active_cic;
- if (!cic || !atomic_read(&cic->ioc->nr_tasks))
+ if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
return;

/*
@@ -2567,9 +2584,9 @@ static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_dispatch_insert(cfqd->queue, rq);

if (!cfqd->active_cic) {
- struct cfq_io_context *cic = RQ_CIC(rq);
+ struct cfq_io_cq *cic = RQ_CIC(rq);

- atomic_long_inc(&cic->ioc->refcount);
+ atomic_long_inc(&cic->icq.ioc->refcount);
cfqd->active_cic = cic;
}

@@ -2652,24 +2669,24 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
cfq_put_cfqg(cfqg);
}

-static void cfq_cic_free_rcu(struct rcu_head *head)
+static void cfq_icq_free_rcu(struct rcu_head *head)
{
- kmem_cache_free(cfq_ioc_pool,
- container_of(head, struct cfq_io_context, rcu_head));
+ kmem_cache_free(cfq_icq_pool,
+ icq_to_cic(container_of(head, struct io_cq, rcu_head)));
}

-static void cfq_cic_free(struct cfq_io_context *cic)
+static void cfq_icq_free(struct io_cq *icq)
{
- call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
+ call_rcu(&icq->rcu_head, cfq_icq_free_rcu);
}

-static void cfq_release_cic(struct cfq_io_context *cic)
+static void cfq_release_icq(struct io_cq *icq)
{
- struct io_context *ioc = cic->ioc;
+ struct io_context *ioc = icq->ioc;

- radix_tree_delete(&ioc->radix_root, cic->q->id);
- hlist_del(&cic->cic_list);
- cfq_cic_free(cic);
+ radix_tree_delete(&ioc->icq_tree, icq->q->id);
+ hlist_del(&icq->ioc_node);
+ cfq_icq_free(icq);
}

static void cfq_put_cooperator(struct cfq_queue *cfqq)
@@ -2705,20 +2722,21 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_put_queue(cfqq);
}

-static void cfq_exit_cic(struct cfq_io_context *cic)
+static void cfq_exit_icq(struct io_cq *icq)
{
+ struct cfq_io_cq *cic = icq_to_cic(icq);
struct cfq_data *cfqd = cic_to_cfqd(cic);
- struct io_context *ioc = cic->ioc;
+ struct io_context *ioc = icq->ioc;

- list_del_init(&cic->queue_list);
+ list_del_init(&icq->q_node);

/*
- * Both setting lookup hint to and clearing it from @cic are done
- * under queue_lock. If it's not pointing to @cic now, it never
+ * Both setting lookup hint to and clearing it from @icq are done
+ * under queue_lock. If it's not pointing to @icq now, it never
* will. Hint assignment itself can race safely.
*/
- if (rcu_dereference_raw(ioc->ioc_data) == cic)
- rcu_assign_pointer(ioc->ioc_data, NULL);
+ if (rcu_dereference_raw(ioc->icq_hint) == icq)
+ rcu_assign_pointer(ioc->icq_hint, NULL);

if (cic->cfqq[BLK_RW_ASYNC]) {
cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
@@ -2731,19 +2749,18 @@ static void cfq_exit_cic(struct cfq_io_context *cic)
}
}

-static struct cfq_io_context *
-cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
+static struct cfq_io_cq *cfq_alloc_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
{
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;

- cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
+ cic = kmem_cache_alloc_node(cfq_icq_pool, gfp_mask | __GFP_ZERO,
cfqd->queue->node);
if (cic) {
cic->ttime.last_end_request = jiffies;
- INIT_LIST_HEAD(&cic->queue_list);
- INIT_HLIST_NODE(&cic->cic_list);
- cic->exit = cfq_exit_cic;
- cic->release = cfq_release_cic;
+ INIT_LIST_HEAD(&cic->icq.q_node);
+ INIT_HLIST_NODE(&cic->icq.ioc_node);
+ cic->icq.exit = cfq_exit_icq;
+ cic->icq.release = cfq_release_icq;
}

return cic;
@@ -2791,7 +2808,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
cfq_clear_cfqq_prio_changed(cfqq);
}

-static void changed_ioprio(struct cfq_io_context *cic)
+static void changed_ioprio(struct cfq_io_cq *cic)
{
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq;
@@ -2802,7 +2819,7 @@ static void changed_ioprio(struct cfq_io_context *cic)
cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc,
+ new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
@@ -2836,7 +2853,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}

#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void changed_cgroup(struct cfq_io_context *cic)
+static void changed_cgroup(struct cfq_io_cq *cic)
{
struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
struct cfq_data *cfqd = cic_to_cfqd(cic);
@@ -2864,7 +2881,7 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
struct io_context *ioc, gfp_t gfp_mask)
{
struct cfq_queue *cfqq, *new_cfqq = NULL;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_group *cfqg;

retry:
@@ -2956,56 +2973,57 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
}

/**
- * cfq_cic_lookup - lookup cfq_io_context
+ * cfq_cic_lookup - lookup cfq_io_cq
* @cfqd: the associated cfq_data
* @ioc: the associated io_context
*
- * Look up cfq_io_context associated with @cfqd - @ioc pair. Must be
- * called with queue_lock held.
+ * Look up cfq_io_cq associated with @cfqd - @ioc pair. Must be called
+ * with queue_lock held.
*/
-static struct cfq_io_context *
+static struct cfq_io_cq *
cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
{
struct request_queue *q = cfqd->queue;
- struct cfq_io_context *cic;
+ struct io_cq *icq;

lockdep_assert_held(cfqd->queue->queue_lock);
if (unlikely(!ioc))
return NULL;

/*
- * cic's are indexed from @ioc using radix tree and hint pointer,
+ * icq's are indexed from @ioc using radix tree and hint pointer,
* both of which are protected with RCU. All removals are done
* holding both q and ioc locks, and we're holding q lock - if we
- * find a cic which points to us, it's guaranteed to be valid.
+ * find a icq which points to us, it's guaranteed to be valid.
*/
rcu_read_lock();
- cic = rcu_dereference(ioc->ioc_data);
- if (cic && cic->q == q)
+ icq = rcu_dereference(ioc->icq_hint);
+ if (icq && icq->q == q)
goto out;

- cic = radix_tree_lookup(&ioc->radix_root, cfqd->queue->id);
- if (cic && cic->q == q)
- rcu_assign_pointer(ioc->ioc_data, cic); /* allowed to race */
+ icq = radix_tree_lookup(&ioc->icq_tree, cfqd->queue->id);
+ if (icq && icq->q == q)
+ rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
else
- cic = NULL;
+ icq = NULL;
out:
rcu_read_unlock();
- return cic;
+ return icq_to_cic(icq);
}

/**
- * cfq_create_cic - create and link a cfq_io_context
+ * cfq_create_cic - create and link a cfq_io_cq
* @cfqd: cfqd of interest
* @gfp_mask: allocation mask
*
- * Make sure cfq_io_context linking %current->io_context and @cfqd exists.
- * If ioc and/or cic doesn't exist, they will be created using @gfp_mask.
+ * Make sure cfq_io_cq linking %current->io_context and @cfqd exists. If
+ * ioc and/or cic doesn't exist, they will be created using @gfp_mask.
*/
static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
{
struct request_queue *q = cfqd->queue;
- struct cfq_io_context *cic = NULL;
+ struct io_cq *icq = NULL;
+ struct cfq_io_cq *cic;
struct io_context *ioc;
int ret = -ENOMEM;

@@ -3016,26 +3034,27 @@ static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
if (!ioc)
goto out;

- cic = cfq_alloc_io_context(cfqd, gfp_mask);
+ cic = cfq_alloc_cic(cfqd, gfp_mask);
if (!cic)
goto out;
+ icq = &cic->icq;

ret = radix_tree_preload(gfp_mask);
if (ret)
goto out;

- cic->ioc = ioc;
- cic->q = cfqd->queue;
+ icq->ioc = ioc;
+ icq->q = cfqd->queue;

- /* lock both q and ioc and try to link @cic */
+ /* lock both q and ioc and try to link @icq */
spin_lock_irq(q->queue_lock);
spin_lock(&ioc->lock);

- ret = radix_tree_insert(&ioc->radix_root, q->id, cic);
+ ret = radix_tree_insert(&ioc->icq_tree, q->id, icq);
if (likely(!ret)) {
- hlist_add_head(&cic->cic_list, &ioc->cic_list);
- list_add(&cic->queue_list, &cfqd->cic_list);
- cic = NULL;
+ hlist_add_head(&icq->ioc_node, &ioc->icq_list);
+ list_add(&icq->q_node, &cfqd->icq_list);
+ icq = NULL;
} else if (ret == -EEXIST) {
/* someone else already did it */
ret = 0;
@@ -3047,29 +3066,28 @@ static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
radix_tree_preload_end();
out:
if (ret)
- printk(KERN_ERR "cfq: cic link failed!\n");
- if (cic)
- cfq_cic_free(cic);
+ printk(KERN_ERR "cfq: icq link failed!\n");
+ if (icq)
+ cfq_icq_free(icq);
return ret;
}

/**
- * cfq_get_io_context - acquire cfq_io_context and bump refcnt on io_context
+ * cfq_get_cic - acquire cfq_io_cq and bump refcnt on io_context
* @cfqd: cfqd to setup cic for
* @gfp_mask: allocation mask
*
- * Return cfq_io_context associating @cfqd and %current->io_context and
+ * Return cfq_io_cq associating @cfqd and %current->io_context and
* bump refcnt on io_context. If ioc or cic doesn't exist, they're created
* using @gfp_mask.
*
* Must be called under queue_lock which may be released and re-acquired.
* This function also may sleep depending on @gfp_mask.
*/
-static struct cfq_io_context *
-cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
+static struct cfq_io_cq *cfq_get_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
{
struct request_queue *q = cfqd->queue;
- struct cfq_io_context *cic = NULL;
+ struct cfq_io_cq *cic = NULL;
struct io_context *ioc;
int err;

@@ -3095,11 +3113,11 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
/* bump @ioc's refcnt and handle changed notifications */
get_io_context(ioc);

- if (unlikely(cic->changed)) {
- if (test_and_clear_bit(CIC_IOPRIO_CHANGED, &cic->changed))
+ if (unlikely(cic->icq.changed)) {
+ if (test_and_clear_bit(ICQ_IOPRIO_CHANGED, &cic->icq.changed))
changed_ioprio(cic);
#ifdef CONFIG_CFQ_GROUP_IOSCHED
- if (test_and_clear_bit(CIC_CGROUP_CHANGED, &cic->changed))
+ if (test_and_clear_bit(ICQ_CGROUP_CHANGED, &cic->icq.changed))
changed_cgroup(cic);
#endif
}
@@ -3120,7 +3138,7 @@ __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)

static void
cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
+ struct cfq_io_cq *cic)
{
if (cfq_cfqq_sync(cfqq)) {
__cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle);
@@ -3158,7 +3176,7 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
*/
static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
+ struct cfq_io_cq *cic)
{
int old_idle, enable_idle;

@@ -3175,8 +3193,9 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,

if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
enable_idle = 0;
- else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
+ else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
+ !cfqd->cfq_slice_idle ||
+ (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
enable_idle = 0;
else if (sample_valid(cic->ttime.ttime_samples)) {
if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle)
@@ -3308,7 +3327,7 @@ static void
cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *rq)
{
- struct cfq_io_context *cic = RQ_CIC(rq);
+ struct cfq_io_cq *cic = RQ_CIC(rq);

cfqd->rq_queued++;
if (rq->cmd_flags & REQ_PRIO)
@@ -3361,7 +3380,7 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
struct cfq_queue *cfqq = RQ_CFQQ(rq);

cfq_log_cfqq(cfqd, cfqq, "insert_request");
- cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
+ cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc);

rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo);
@@ -3411,7 +3430,7 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd)

static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- struct cfq_io_context *cic = cfqd->active_cic;
+ struct cfq_io_cq *cic = cfqd->active_cic;

/* If the queue already has requests, don't wait */
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
@@ -3548,7 +3567,7 @@ static int cfq_may_queue(struct request_queue *q, int rw)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;

/*
@@ -3563,7 +3582,7 @@ static int cfq_may_queue(struct request_queue *q, int rw)

cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) {
- cfq_init_prio_data(cfqq, cic->ioc);
+ cfq_init_prio_data(cfqq, cic->icq.ioc);

return __cfq_may_queue(cfqq);
}
@@ -3584,7 +3603,7 @@ static void cfq_put_request(struct request *rq)
BUG_ON(!cfqq->allocated[rw]);
cfqq->allocated[rw]--;

- put_io_context(RQ_CIC(rq)->ioc, cfqq->cfqd->queue);
+ put_io_context(RQ_CIC(rq)->icq.ioc, cfqq->cfqd->queue);

rq->elevator_private[0] = NULL;
rq->elevator_private[1] = NULL;
@@ -3598,7 +3617,7 @@ static void cfq_put_request(struct request *rq)
}

static struct cfq_queue *
-cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
+cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic,
struct cfq_queue *cfqq)
{
cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
@@ -3613,7 +3632,7 @@ cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
* was the last process referring to said cfqq.
*/
static struct cfq_queue *
-split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
+split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
{
if (cfqq_process_refs(cfqq) == 1) {
cfqq->pid = current->pid;
@@ -3636,7 +3655,7 @@ static int
cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
const int rw = rq_data_dir(rq);
const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
@@ -3644,14 +3663,14 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
might_sleep_if(gfp_mask & __GFP_WAIT);

spin_lock_irq(q->queue_lock);
- cic = cfq_get_io_context(cfqd, gfp_mask);
+ cic = cfq_get_cic(cfqd, gfp_mask);
if (!cic)
goto queue_fail;

new_queue:
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq || cfqq == &cfqd->oom_cfqq) {
- cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
+ cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask);
cic_set_cfqq(cic, cfqq, is_sync);
} else {
/*
@@ -3677,7 +3696,7 @@ new_queue:
cfqq->allocated[rw]++;

cfqq->ref++;
- rq->elevator_private[0] = cic;
+ rq->elevator_private[0] = &cic->icq;
rq->elevator_private[1] = cfqq;
rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
spin_unlock_irq(q->queue_lock);
@@ -3791,15 +3810,14 @@ static void cfq_exit_queue(struct elevator_queue *e)
if (cfqd->active_queue)
__cfq_slice_expired(cfqd, cfqd->active_queue, 0);

- while (!list_empty(&cfqd->cic_list)) {
- struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
- struct cfq_io_context,
- queue_list);
- struct io_context *ioc = cic->ioc;
+ while (!list_empty(&cfqd->icq_list)) {
+ struct io_cq *icq = list_entry(cfqd->icq_list.next,
+ struct io_cq, q_node);
+ struct io_context *ioc = icq->ioc;

spin_lock(&ioc->lock);
- cfq_exit_cic(cic);
- cfq_release_cic(cic);
+ cfq_exit_icq(icq);
+ cfq_release_icq(icq);
spin_unlock(&ioc->lock);
}

@@ -3904,7 +3922,7 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->oom_cfqq.ref++;
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);

- INIT_LIST_HEAD(&cfqd->cic_list);
+ INIT_LIST_HEAD(&cfqd->icq_list);

cfqd->queue = q;

@@ -3942,8 +3960,8 @@ static void cfq_slab_kill(void)
*/
if (cfq_pool)
kmem_cache_destroy(cfq_pool);
- if (cfq_ioc_pool)
- kmem_cache_destroy(cfq_ioc_pool);
+ if (cfq_icq_pool)
+ kmem_cache_destroy(cfq_icq_pool);
}

static int __init cfq_slab_setup(void)
@@ -3952,8 +3970,8 @@ static int __init cfq_slab_setup(void)
if (!cfq_pool)
goto fail;

- cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
- if (!cfq_ioc_pool)
+ cfq_icq_pool = KMEM_CACHE(cfq_io_cq, 0);
+ if (!cfq_icq_pool)
goto fail;

return 0;
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index b2b75a5..d15ca65 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -5,38 +5,23 @@
#include <linux/rcupdate.h>
#include <linux/workqueue.h>

-struct cfq_queue;
-struct cfq_ttime {
- unsigned long last_end_request;
-
- unsigned long ttime_total;
- unsigned long ttime_samples;
- unsigned long ttime_mean;
-};
-
enum {
- CIC_IOPRIO_CHANGED,
- CIC_CGROUP_CHANGED,
+ ICQ_IOPRIO_CHANGED,
+ ICQ_CGROUP_CHANGED,
};

-struct cfq_io_context {
- struct request_queue *q;
-
- struct cfq_queue *cfqq[2];
-
- struct io_context *ioc;
-
- struct cfq_ttime ttime;
-
- struct list_head queue_list;
- struct hlist_node cic_list;
+struct io_cq {
+ struct request_queue *q;
+ struct io_context *ioc;

- unsigned long changed;
+ struct list_head q_node;
+ struct hlist_node ioc_node;

- void (*exit)(struct cfq_io_context *);
- void (*release)(struct cfq_io_context *);
+ unsigned long changed;
+ struct rcu_head rcu_head;

- struct rcu_head rcu_head;
+ void (*exit)(struct io_cq *);
+ void (*release)(struct io_cq *);
};

/*
@@ -58,9 +43,9 @@ struct io_context {
int nr_batch_requests; /* Number of requests left in the batch */
unsigned long last_waited; /* Time last woken after wait for request */

- struct radix_tree_root radix_root;
- struct hlist_head cic_list;
- void __rcu *ioc_data;
+ struct radix_tree_root icq_tree;
+ struct io_cq __rcu *icq_hint;
+ struct hlist_head icq_list;

struct work_struct release_work;
};
--
1.7.3.1

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