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block, cfq: reorganize cfq_io_context into generic and cfq specific parts 

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@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hifive-unleashed-5.1
Tejun Heo 2011-12-14 00:33:41 +01:00 committed by Jens Axboe
parent 22f746e235
commit c586980732
3 changed files with 175 additions and 174 deletions
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58
block/blk-ioc.c
View File

@ -46,7 +46,7 @@ EXPORT_SYMBOL(get_io_context);
/* /*
* Slow path for ioc release in put_io_context(). Performs double-lock * 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) 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); spin_lock_irq(&ioc->lock);
while (!hlist_empty(&ioc->cic_list)) { while (!hlist_empty(&ioc->icq_list)) {
struct cfq_io_context *cic = hlist_entry(ioc->cic_list.first, struct io_cq *icq = hlist_entry(ioc->icq_list.first,
struct cfq_io_context, struct io_cq, ioc_node);
cic_list); struct request_queue *this_q = icq->q;
struct request_queue *this_q = cic->q;
if (this_q != last_q) { if (this_q != last_q) {
/* /*
@ -89,8 +88,8 @@ static void ioc_release_fn(struct work_struct *work)
continue; continue;
} }
ioc_release_depth_inc(this_q); ioc_release_depth_inc(this_q);
cic->exit(cic); icq->exit(icq);
cic->release(cic); icq->release(icq);
ioc_release_depth_dec(this_q); ioc_release_depth_dec(this_q);
} }
@ -131,10 +130,10 @@ void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
return; 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. * 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 * The inner ioc->lock should be held to walk our icq_list and then
* for each cic the outer matching queue_lock should be grabbed. * for each icq the outer matching queue_lock should be grabbed.
* ie. We need to do reverse-order double lock dancing. * ie. We need to do reverse-order double lock dancing.
* *
* Another twist is that we are often called with one of the * 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, spin_lock_irqsave_nested(&ioc->lock, flags,
ioc_release_depth(locked_q)); ioc_release_depth(locked_q));
while (!hlist_empty(&ioc->cic_list)) { while (!hlist_empty(&ioc->icq_list)) {
struct cfq_io_context *cic = hlist_entry(ioc->cic_list.first, struct io_cq *icq = hlist_entry(ioc->icq_list.first,
struct cfq_io_context, struct io_cq, ioc_node);
cic_list); struct request_queue *this_q = icq->q;
struct request_queue *this_q = cic->q;
if (this_q != last_q) { if (this_q != last_q) {
if (last_q && last_q != locked_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; continue;
} }
ioc_release_depth_inc(this_q); ioc_release_depth_inc(this_q);
cic->exit(cic); icq->exit(icq);
cic->release(cic); icq->release(icq);
ioc_release_depth_dec(this_q); 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); spin_unlock_irqrestore(&ioc->lock, flags);
/* if no cic's left, we're done; otherwise, kick release_work */ /* if no icq is left, we're done; otherwise, kick release_work */
if (hlist_empty(&ioc->cic_list)) if (hlist_empty(&ioc->icq_list))
kmem_cache_free(iocontext_cachep, ioc); kmem_cache_free(iocontext_cachep, ioc);
else else
schedule_work(&ioc->release_work); 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_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1); atomic_set(&ioc->nr_tasks, 1);
spin_lock_init(&ioc->lock); spin_lock_init(&ioc->lock);
INIT_RADIX_TREE(&ioc->radix_root, GFP_ATOMIC | __GFP_HIGH); INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ioc->cic_list); INIT_HLIST_HEAD(&ioc->icq_list);
INIT_WORK(&ioc->release_work, ioc_release_fn); INIT_WORK(&ioc->release_work, ioc_release_fn);
/* try to install, somebody might already have beaten us to it */ /* 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) void ioc_set_changed(struct io_context *ioc, int which)
{ {
struct cfq_io_context *cic; struct io_cq *icq;
struct hlist_node *n; struct hlist_node *n;
hlist_for_each_entry(cic, n, &ioc->cic_list, cic_list) hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
set_bit(which, &cic->changed); set_bit(which, &icq->changed);
} }
/** /**
@ -282,8 +280,8 @@ void ioc_set_changed(struct io_context *ioc, int which)
* @ioc: io_context of interest * @ioc: io_context of interest
* @ioprio: new ioprio * @ioprio: new ioprio
* *
* @ioc's ioprio has changed to @ioprio. Set %CIC_IOPRIO_CHANGED for all * @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
* cic's. iosched is responsible for checking the bit and applying it on * icq's. iosched is responsible for checking the bit and applying it on
* request issue path. * request issue path.
*/ */
void ioc_ioprio_changed(struct io_context *ioc, int ioprio) 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); spin_lock_irqsave(&ioc->lock, flags);
ioc->ioprio = ioprio; ioc->ioprio = ioprio;
ioc_set_changed(ioc, CIC_IOPRIO_CHANGED); ioc_set_changed(ioc, ICQ_IOPRIO_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags); 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_cgroup_changed - notify cgroup change
* @ioc: io_context of interest * @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 * iosched is responsible for checking the bit and applying it on request
* issue path. * issue path.
*/ */
@ -309,7 +307,7 @@ void ioc_cgroup_changed(struct io_context *ioc)
unsigned long flags; unsigned long flags;
spin_lock_irqsave(&ioc->lock, 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); spin_unlock_irqrestore(&ioc->lock, flags);
} }

248
block/cfq-iosched.c
View File

@ -54,13 +54,12 @@ static const int cfq_hist_divisor = 4;
#define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32) #define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32)
#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
#define RQ_CIC(rq) \ #define RQ_CIC(rq) icq_to_cic((rq)->elevator_private[0])
((struct cfq_io_context *) (rq)->elevator_private[0])
#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1]) #define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1])
#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2]) #define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2])
static struct kmem_cache *cfq_pool; 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_PRIO_LISTS IOPRIO_BE_NR
#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) #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 sample_valid(samples) ((samples) > 80)
#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node) #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 * 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 * 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_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 * Per block device queue structure
*/ */
@ -261,7 +274,7 @@ struct cfq_data {
struct work_struct unplug_work; struct work_struct unplug_work;
struct cfq_queue *active_queue; struct cfq_queue *active_queue;
struct cfq_io_context *active_cic; struct cfq_io_cq *active_cic;
/* /*
* async queue for each priority case * async queue for each priority case
@ -284,7 +297,7 @@ struct cfq_data {
unsigned int cfq_group_idle; unsigned int cfq_group_idle;
unsigned int cfq_latency; unsigned int cfq_latency;
struct list_head cic_list; struct list_head icq_list;
/* /*
* Fallback dummy cfqq for extreme OOM conditions * 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 void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool, static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
struct io_context *, gfp_t); struct io_context *, gfp_t);
static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, static struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *, struct io_context *);
struct io_context *);
static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
bool is_sync) {
/* 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]; return cic->cfqq[is_sync];
} }
static inline void cic_set_cfqq(struct cfq_io_context *cic, static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
struct cfq_queue *cfqq, bool is_sync) bool is_sync)
{ {
cic->cfqq[is_sync] = cfqq; 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) cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{ {
struct task_struct *tsk = current; struct task_struct *tsk = current;
struct cfq_io_context *cic; struct cfq_io_cq *cic;
struct cfq_queue *cfqq; struct cfq_queue *cfqq;
cic = cfq_cic_lookup(cfqd, tsk->io_context); 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 bio *bio)
{ {
struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_io_context *cic; struct cfq_io_cq *cic;
struct cfq_queue *cfqq; 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 * and %current are guaranteed to be equal. Avoid lookup which
* requires queue_lock by using @rq's cic. * 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); cic = RQ_CIC(rq);
} else { } else {
cic = cfq_cic_lookup(cfqd, current->io_context); 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; cfqd->active_queue = NULL;
if (cfqd->active_cic) { 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; 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) static void cfq_arm_slice_timer(struct cfq_data *cfqd)
{ {
struct cfq_queue *cfqq = cfqd->active_queue; struct cfq_queue *cfqq = cfqd->active_queue;
struct cfq_io_context *cic; struct cfq_io_cq *cic;
unsigned long sl, group_idle = 0; 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 * task has exited, don't wait
*/ */
cic = cfqd->active_cic; cic = cfqd->active_cic;
if (!cic || !atomic_read(&cic->ioc->nr_tasks)) if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
return; return;
/* /*
@ -2567,9 +2584,9 @@ static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_dispatch_insert(cfqd->queue, rq); cfq_dispatch_insert(cfqd->queue, rq);
if (!cfqd->active_cic) { 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; cfqd->active_cic = cic;
} }
@ -2652,24 +2669,24 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
cfq_put_cfqg(cfqg); 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, kmem_cache_free(cfq_icq_pool,
container_of(head, struct cfq_io_context, rcu_head)); 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); radix_tree_delete(&ioc->icq_tree, icq->q->id);
hlist_del(&cic->cic_list); hlist_del(&icq->ioc_node);
cfq_cic_free(cic); cfq_icq_free(icq);
} }
static void cfq_put_cooperator(struct cfq_queue *cfqq) 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); 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 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 * Both setting lookup hint to and clearing it from @icq are done
* under queue_lock. If it's not pointing to @cic now, it never * under queue_lock. If it's not pointing to @icq now, it never
* will. Hint assignment itself can race safely. * will. Hint assignment itself can race safely.
*/ */
if (rcu_dereference_raw(ioc->ioc_data) == cic) if (rcu_dereference_raw(ioc->icq_hint) == icq)
rcu_assign_pointer(ioc->ioc_data, NULL); rcu_assign_pointer(ioc->icq_hint, NULL);
if (cic->cfqq[BLK_RW_ASYNC]) { if (cic->cfqq[BLK_RW_ASYNC]) {
cfq_exit_cfqq(cfqd, 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 * static struct cfq_io_cq *cfq_alloc_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
cfq_alloc_io_context(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); cfqd->queue->node);
if (cic) { if (cic) {
cic->ttime.last_end_request = jiffies; cic->ttime.last_end_request = jiffies;
INIT_LIST_HEAD(&cic->queue_list); INIT_LIST_HEAD(&cic->icq.q_node);
INIT_HLIST_NODE(&cic->cic_list); INIT_HLIST_NODE(&cic->icq.ioc_node);
cic->exit = cfq_exit_cic; cic->icq.exit = cfq_exit_icq;
cic->release = cfq_release_cic; cic->icq.release = cfq_release_icq;
} }
return cic; 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); 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_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq; struct cfq_queue *cfqq;
@ -2802,7 +2819,7 @@ static void changed_ioprio(struct cfq_io_context *cic)
cfqq = cic->cfqq[BLK_RW_ASYNC]; cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) { if (cfqq) {
struct cfq_queue *new_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); GFP_ATOMIC);
if (new_cfqq) { if (new_cfqq) {
cic->cfqq[BLK_RW_ASYNC] = 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 #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_queue *sync_cfqq = cic_to_cfqq(cic, 1);
struct cfq_data *cfqd = cic_to_cfqd(cic); 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 io_context *ioc, gfp_t gfp_mask)
{ {
struct cfq_queue *cfqq, *new_cfqq = NULL; struct cfq_queue *cfqq, *new_cfqq = NULL;
struct cfq_io_context *cic; struct cfq_io_cq *cic;
struct cfq_group *cfqg; struct cfq_group *cfqg;
retry: 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 * @cfqd: the associated cfq_data
* @ioc: the associated io_context * @ioc: the associated io_context
* *
* Look up cfq_io_context associated with @cfqd - @ioc pair. Must be * Look up cfq_io_cq associated with @cfqd - @ioc pair. Must be called
* called with queue_lock held. * 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) cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
{ {
struct request_queue *q = cfqd->queue; struct request_queue *q = cfqd->queue;
struct cfq_io_context *cic; struct io_cq *icq;
lockdep_assert_held(cfqd->queue->queue_lock); lockdep_assert_held(cfqd->queue->queue_lock);
if (unlikely(!ioc)) if (unlikely(!ioc))
return NULL; 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 * 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 * 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(); rcu_read_lock();
cic = rcu_dereference(ioc->ioc_data); icq = rcu_dereference(ioc->icq_hint);
if (cic && cic->q == q) if (icq && icq->q == q)
goto out; goto out;
cic = radix_tree_lookup(&ioc->radix_root, cfqd->queue->id); icq = radix_tree_lookup(&ioc->icq_tree, cfqd->queue->id);
if (cic && cic->q == q) if (icq && icq->q == q)
rcu_assign_pointer(ioc->ioc_data, cic); /* allowed to race */ rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
else else
cic = NULL; icq = NULL;
out: out:
rcu_read_unlock(); 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 * @cfqd: cfqd of interest
* @gfp_mask: allocation mask * @gfp_mask: allocation mask
* *
* Make sure cfq_io_context linking %current->io_context and @cfqd exists. * Make sure cfq_io_cq linking %current->io_context and @cfqd exists. If
* If ioc and/or cic doesn't exist, they will be created using @gfp_mask. * 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) static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
{ {
struct request_queue *q = cfqd->queue; 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; struct io_context *ioc;
int ret = -ENOMEM; int ret = -ENOMEM;
@ -3016,26 +3034,27 @@ static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
if (!ioc) if (!ioc)
goto out; goto out;
cic = cfq_alloc_io_context(cfqd, gfp_mask); cic = cfq_alloc_cic(cfqd, gfp_mask);
if (!cic) if (!cic)
goto out; goto out;
icq = &cic->icq;
ret = radix_tree_preload(gfp_mask); ret = radix_tree_preload(gfp_mask);
if (ret) if (ret)
goto out; goto out;
cic->ioc = ioc; icq->ioc = ioc;
cic->q = cfqd->queue; 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_irq(q->queue_lock);
spin_lock(&ioc->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)) { if (likely(!ret)) {
hlist_add_head(&cic->cic_list, &ioc->cic_list); hlist_add_head(&icq->ioc_node, &ioc->icq_list);
list_add(&cic->queue_list, &cfqd->cic_list); list_add(&icq->q_node, &cfqd->icq_list);
cic = NULL; icq = NULL;
} else if (ret == -EEXIST) { } else if (ret == -EEXIST) {
/* someone else already did it */ /* someone else already did it */
ret = 0; ret = 0;
@ -3047,29 +3066,28 @@ static int cfq_create_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
radix_tree_preload_end(); radix_tree_preload_end();
out: out:
if (ret) if (ret)
printk(KERN_ERR "cfq: cic link failed!\n"); printk(KERN_ERR "cfq: icq link failed!\n");
if (cic) if (icq)
cfq_cic_free(cic); cfq_icq_free(icq);
return ret; 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 * @cfqd: cfqd to setup cic for
* @gfp_mask: allocation mask * @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 * bump refcnt on io_context. If ioc or cic doesn't exist, they're created
* using @gfp_mask. * using @gfp_mask.
* *
* Must be called under queue_lock which may be released and re-acquired. * Must be called under queue_lock which may be released and re-acquired.
* This function also may sleep depending on @gfp_mask. * This function also may sleep depending on @gfp_mask.
*/ */
static struct cfq_io_context * static struct cfq_io_cq *cfq_get_cic(struct cfq_data *cfqd, gfp_t gfp_mask)
cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
{ {
struct request_queue *q = cfqd->queue; struct request_queue *q = cfqd->queue;
struct cfq_io_context *cic = NULL; struct cfq_io_cq *cic = NULL;
struct io_context *ioc; struct io_context *ioc;
int err; 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 */ /* bump @ioc's refcnt and handle changed notifications */
get_io_context(ioc); get_io_context(ioc);
if (unlikely(cic->changed)) { if (unlikely(cic->icq.changed)) {
if (test_and_clear_bit(CIC_IOPRIO_CHANGED, &cic->changed)) if (test_and_clear_bit(ICQ_IOPRIO_CHANGED, &cic->icq.changed))
changed_ioprio(cic); changed_ioprio(cic);
#ifdef CONFIG_CFQ_GROUP_IOSCHED #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); changed_cgroup(cic);
#endif #endif
} }
@ -3120,7 +3138,7 @@ __cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)
static void static void
cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq, 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)) { if (cfq_cfqq_sync(cfqq)) {
__cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle); __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 static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, 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; 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)) if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
enable_idle = 0; enable_idle = 0;
else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle || else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
(!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq))) !cfqd->cfq_slice_idle ||
(!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
enable_idle = 0; enable_idle = 0;
else if (sample_valid(cic->ttime.ttime_samples)) { else if (sample_valid(cic->ttime.ttime_samples)) {
if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle) 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, cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *rq) struct request *rq)
{ {
struct cfq_io_context *cic = RQ_CIC(rq); struct cfq_io_cq *cic = RQ_CIC(rq);
cfqd->rq_queued++; cfqd->rq_queued++;
if (rq->cmd_flags & REQ_PRIO) 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); struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_log_cfqq(cfqd, cfqq, "insert_request"); 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)]); rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo); 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) 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 the queue already has requests, don't wait */
if (!RB_EMPTY_ROOT(&cfqq->sort_list)) 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 cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current; struct task_struct *tsk = current;
struct cfq_io_context *cic; struct cfq_io_cq *cic;
struct cfq_queue *cfqq; 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)); cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) { if (cfqq) {
cfq_init_prio_data(cfqq, cic->ioc); cfq_init_prio_data(cfqq, cic->icq.ioc);
return __cfq_may_queue(cfqq); return __cfq_may_queue(cfqq);
} }
@ -3584,7 +3603,7 @@ static void cfq_put_request(struct request *rq)
BUG_ON(!cfqq->allocated[rw]); BUG_ON(!cfqq->allocated[rw]);
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[0] = NULL;
rq->elevator_private[1] = NULL; rq->elevator_private[1] = NULL;
@ -3598,7 +3617,7 @@ static void cfq_put_request(struct request *rq)
} }
static struct cfq_queue * 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) struct cfq_queue *cfqq)
{ {
cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_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. * was the last process referring to said cfqq.
*/ */
static struct cfq_queue * 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) { if (cfqq_process_refs(cfqq) == 1) {
cfqq->pid = current->pid; cfqq->pid = current->pid;
@ -3636,7 +3655,7 @@ static int
cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
{ {
struct cfq_data *cfqd = q->elevator->elevator_data; 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 int rw = rq_data_dir(rq);
const bool is_sync = rq_is_sync(rq); const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq; 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); might_sleep_if(gfp_mask & __GFP_WAIT);
spin_lock_irq(q->queue_lock); spin_lock_irq(q->queue_lock);
cic = cfq_get_io_context(cfqd, gfp_mask); cic = cfq_get_cic(cfqd, gfp_mask);
if (!cic) if (!cic)
goto queue_fail; goto queue_fail;
new_queue: new_queue:
cfqq = cic_to_cfqq(cic, is_sync); cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq || cfqq == &cfqd->oom_cfqq) { 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); cic_set_cfqq(cic, cfqq, is_sync);
} else { } else {
/* /*
@ -3677,7 +3696,7 @@ new_queue:
cfqq->allocated[rw]++; cfqq->allocated[rw]++;
cfqq->ref++; cfqq->ref++;
rq->elevator_private[0] = cic; rq->elevator_private[0] = &cic->icq;
rq->elevator_private[1] = cfqq; rq->elevator_private[1] = cfqq;
rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg); rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
spin_unlock_irq(q->queue_lock); spin_unlock_irq(q->queue_lock);
@ -3791,15 +3810,14 @@ static void cfq_exit_queue(struct elevator_queue *e)
if (cfqd->active_queue) if (cfqd->active_queue)
__cfq_slice_expired(cfqd, cfqd->active_queue, 0); __cfq_slice_expired(cfqd, cfqd->active_queue, 0);
while (!list_empty(&cfqd->cic_list)) { while (!list_empty(&cfqd->icq_list)) {
struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, struct io_cq *icq = list_entry(cfqd->icq_list.next,
struct cfq_io_context, struct io_cq, q_node);
queue_list); struct io_context *ioc = icq->ioc;
struct io_context *ioc = cic->ioc;
spin_lock(&ioc->lock); spin_lock(&ioc->lock);
cfq_exit_cic(cic); cfq_exit_icq(icq);
cfq_release_cic(cic); cfq_release_icq(icq);
spin_unlock(&ioc->lock); spin_unlock(&ioc->lock);
} }
@ -3904,7 +3922,7 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->oom_cfqq.ref++; cfqd->oom_cfqq.ref++;
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group); 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; cfqd->queue = q;
@ -3942,8 +3960,8 @@ static void cfq_slab_kill(void)
*/ */
if (cfq_pool) if (cfq_pool)
kmem_cache_destroy(cfq_pool); kmem_cache_destroy(cfq_pool);
if (cfq_ioc_pool) if (cfq_icq_pool)
kmem_cache_destroy(cfq_ioc_pool); kmem_cache_destroy(cfq_icq_pool);
} }
static int __init cfq_slab_setup(void) static int __init cfq_slab_setup(void)
@ -3952,8 +3970,8 @@ static int __init cfq_slab_setup(void)
if (!cfq_pool) if (!cfq_pool)
goto fail; goto fail;
cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); cfq_icq_pool = KMEM_CACHE(cfq_io_cq, 0);
if (!cfq_ioc_pool) if (!cfq_icq_pool)
goto fail; goto fail;
return 0; return 0;

43
include/linux/iocontext.h
View File

@ -5,38 +5,23 @@
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/workqueue.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 { enum {
CIC_IOPRIO_CHANGED, ICQ_IOPRIO_CHANGED,
CIC_CGROUP_CHANGED, ICQ_CGROUP_CHANGED,
}; };
struct cfq_io_context { struct io_cq {
struct request_queue *q; struct request_queue *q;
struct io_context *ioc;
struct cfq_queue *cfqq[2]; struct list_head q_node;
struct hlist_node ioc_node;
struct io_context *ioc; unsigned long changed;
struct rcu_head rcu_head;
struct cfq_ttime ttime; void (*exit)(struct io_cq *);
void (*release)(struct io_cq *);
struct list_head queue_list;
struct hlist_node cic_list;
unsigned long changed;
void (*exit)(struct cfq_io_context *);
void (*release)(struct cfq_io_context *);
struct rcu_head rcu_head;
}; };
/* /*
@ -58,9 +43,9 @@ struct io_context {
int nr_batch_requests; /* Number of requests left in the batch */ int nr_batch_requests; /* Number of requests left in the batch */
unsigned long last_waited; /* Time last woken after wait for request */ unsigned long last_waited; /* Time last woken after wait for request */
struct radix_tree_root radix_root; struct radix_tree_root icq_tree;
struct hlist_head cic_list; struct io_cq __rcu *icq_hint;
void __rcu *ioc_data; struct hlist_head icq_list;
struct work_struct release_work; struct work_struct release_work;
}; };