[PATCH 04/20] io-controller: Modify cfq to make use of flat elevator fair queuing

Vivek Goyal
2009-06-19T20:39:48Z

This patch changes cfq to use fair queuing code from elevator layer.

Signed-off-by: Nauman Rafique <nauman@google.com>
Signed-off-by: Fabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
block/Kconfig.iosched | 3 +-
block/cfq-iosched.c | 1106 +++++++++------------------------------------
include/linux/iocontext.h | 5 -
3 files changed, 222 insertions(+), 892 deletions(-)

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 3398134..dd5224d 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -3,7 +3,7 @@ if BLOCK
menu "IO Schedulers"

config ELV_FAIR_QUEUING
- bool "Elevator Fair Queuing Support"
+ bool
default n
---help---
Traditionally only cfq had notion of multiple queues and it did
@@ -46,6 +46,7 @@ config IOSCHED_DEADLINE

config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
+ select ELV_FAIR_QUEUING
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a55a9bd..995c8dd 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -12,7 +12,6 @@
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
-
/*
* tunables
*/
@@ -23,15 +22,7 @@ static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
static const int cfq_back_max = 16 * 1024;
/* penalty of a backwards seek */
static const int cfq_back_penalty = 2;
-static const int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
static const int cfq_slice_async_rq = 2;
-static int cfq_slice_idle = HZ / 125;
-
-/*
- * offset from end of service tree
- */
-#define CFQ_IDLE_DELAY (HZ / 5)

/*
* below this threshold, we consider thinktime immediate
@@ -43,7 +34,7 @@ static int cfq_slice_idle = HZ / 125;

#define RQ_CIC(rq) \
((struct cfq_io_context *) (rq)->elevator_private)
-#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
+#define RQ_CFQQ(rq) (struct cfq_queue *) (ioq_sched_queue((rq)->ioq))

static struct kmem_cache *cfq_pool;
static struct kmem_cache *cfq_ioc_pool;
@@ -53,8 +44,6 @@ static struct completion *ioc_gone;
static DEFINE_SPINLOCK(ioc_gone_lock);

#define CFQ_PRIO_LISTS IOPRIO_BE_NR
-#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)

#define sample_valid(samples) ((samples) > 80)

@@ -75,12 +64,6 @@ struct cfq_rb_root {
*/
struct cfq_data {
struct request_queue *queue;
-
- /*
- * rr list of queues with requests and the count of them
- */
- struct cfq_rb_root service_tree;
-
/*
* Each priority tree is sorted by next_request position. These
* trees are used when determining if two or more queues are
@@ -88,41 +71,11 @@ struct cfq_data {
*/
struct rb_root prio_trees[CFQ_PRIO_LISTS];

- unsigned int busy_queues;
- /*
- * Used to track any pending rt requests so we can pre-empt current
- * non-RT cfqq in service when this value is non-zero.
- */
- unsigned int busy_rt_queues;
-
- int rq_in_driver;
int sync_flight;

- /*
- * queue-depth detection
- */
- int rq_queued;
- int hw_tag;
- int hw_tag_samples;
- int rq_in_driver_peak;
-
- /*
- * idle window management
- */
- struct timer_list idle_slice_timer;
- struct work_struct unplug_work;
-
- struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;

- /*
- * async queue for each priority case
- */
- struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
- struct cfq_queue *async_idle_cfqq;
-
sector_t last_position;
- unsigned long last_end_request;

/*
* tunables, see top of file
@@ -131,9 +84,7 @@ struct cfq_data {
unsigned int cfq_fifo_expire[2];
unsigned int cfq_back_penalty;
unsigned int cfq_back_max;
- unsigned int cfq_slice[2];
unsigned int cfq_slice_async_rq;
- unsigned int cfq_slice_idle;

struct list_head cic_list;
};
@@ -142,16 +93,11 @@ struct cfq_data {
* Per process-grouping structure
*/
struct cfq_queue {
- /* reference count */
- atomic_t ref;
+ struct io_queue *ioq;
/* various state flags, see below */
unsigned int flags;
/* parent cfq_data */
struct cfq_data *cfqd;
- /* service_tree member */
- struct rb_node rb_node;
- /* service_tree key */
- unsigned long rb_key;
/* prio tree member */
struct rb_node p_node;
/* prio tree root we belong to, if any */
@@ -167,33 +113,23 @@ struct cfq_queue {
/* fifo list of requests in sort_list */
struct list_head fifo;

- unsigned long slice_end;
- long slice_resid;
unsigned int slice_dispatch;

/* pending metadata requests */
int meta_pending;
- /* number of requests that are on the dispatch list or inside driver */
- int dispatched;

/* io prio of this group */
- unsigned short ioprio, org_ioprio;
- unsigned short ioprio_class, org_ioprio_class;
+ unsigned short org_ioprio;
+ unsigned short org_ioprio_class;

pid_t pid;
};

enum cfqq_state_flags {
- CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */
- CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
- CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */
CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */
CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
- CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */
CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
- CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
- CFQ_CFQQ_FLAG_sync, /* synchronous queue */
CFQ_CFQQ_FLAG_coop, /* has done a coop jump of the queue */
};

@@ -211,16 +147,10 @@ static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
}

-CFQ_CFQQ_FNS(on_rr);
-CFQ_CFQQ_FNS(wait_request);
-CFQ_CFQQ_FNS(must_dispatch);
CFQ_CFQQ_FNS(must_alloc);
CFQ_CFQQ_FNS(must_alloc_slice);
CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(slice_new);
-CFQ_CFQQ_FNS(sync);
CFQ_CFQQ_FNS(coop);
#undef CFQ_CFQQ_FNS

@@ -259,66 +189,27 @@ static inline int cfq_bio_sync(struct bio *bio)
return 0;
}

-/*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
- */
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
+static inline struct io_group *cfqq_to_io_group(struct cfq_queue *cfqq)
{
- if (cfqd->busy_queues) {
- cfq_log(cfqd, "schedule dispatch");
- kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
- }
+ return ioq_to_io_group(cfqq->ioq);
}

-static int cfq_queue_empty(struct request_queue *q)
+static inline int cfq_class_idle(struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- return !cfqd->busy_queues;
+ return elv_ioq_class_idle(cfqq->ioq);
}

-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync,
- unsigned short prio)
-{
- const int base_slice = cfqd->cfq_slice[sync];
-
- WARN_ON(prio >= IOPRIO_BE_NR);
-
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
-}
-
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfq_cfqq_sync(struct cfq_queue *cfqq)
{
- cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
- cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
+ return elv_ioq_sync(cfqq->ioq);
}

-/*
- * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
- * isn't valid until the first request from the dispatch is activated
- * and the slice time set.
- */
-static inline int cfq_slice_used(struct cfq_queue *cfqq)
+static inline int cfqq_is_active_queue(struct cfq_queue *cfqq)
{
- if (cfq_cfqq_slice_new(cfqq))
- return 0;
- if (time_before(jiffies, cfqq->slice_end))
- return 0;
+ struct cfq_data *cfqd = cfqq->cfqd;
+ struct elevator_queue *e = cfqd->queue->elevator;

- return 1;
+ return (elv_active_sched_queue(e) == cfqq);
}

/*
@@ -417,33 +308,6 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
}

/*
- * The below is leftmost cache rbtree addon
- */
-static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
-{
- if (!root->left)
- root->left = rb_first(&root->rb);
-
- if (root->left)
- return rb_entry(root->left, struct cfq_queue, rb_node);
-
- return NULL;
-}
-
-static void rb_erase_init(struct rb_node *n, struct rb_root *root)
-{
- rb_erase(n, root);
- RB_CLEAR_NODE(n);
-}
-
-static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
-{
- if (root->left == n)
- root->left = NULL;
- rb_erase_init(n, &root->rb);
-}
-
-/*
* would be nice to take fifo expire time into account as well
*/
static struct request *
@@ -456,10 +320,10 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,

BUG_ON(RB_EMPTY_NODE(&last->rb_node));

- if (rbprev)
+ if (rbprev != NULL)
prev = rb_entry_rq(rbprev);

- if (rbnext)
+ if (rbnext != NULL)
next = rb_entry_rq(rbnext);
else {
rbnext = rb_first(&cfqq->sort_list);
@@ -470,95 +334,6 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
return cfq_choose_req(cfqd, next, prev);
}

-static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- /*
- * just an approximation, should be ok.
- */
- return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
- cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
-}
-
-/*
- * The cfqd->service_tree holds all pending cfq_queue's that have
- * requests waiting to be processed. It is sorted in the order that
- * we will service the queues.
- */
-static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int add_front)
-{
- struct rb_node **p, *parent;
- struct cfq_queue *__cfqq;
- unsigned long rb_key;
- int left;
-
- if (cfq_class_idle(cfqq)) {
- rb_key = CFQ_IDLE_DELAY;
- parent = rb_last(&cfqd->service_tree.rb);
- if (parent && parent != &cfqq->rb_node) {
- __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
- rb_key += __cfqq->rb_key;
- } else
- rb_key += jiffies;
- } else if (!add_front) {
- rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
- rb_key += cfqq->slice_resid;
- cfqq->slice_resid = 0;
- } else
- rb_key = 0;
-
- if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
- /*
- * same position, nothing more to do
- */
- if (rb_key == cfqq->rb_key)
- return;
-
- cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
- }
-
- left = 1;
- parent = NULL;
- p = &cfqd->service_tree.rb.rb_node;
- while (*p) {
- struct rb_node **n;
-
- parent = *p;
- __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-
- /*
- * sort RT queues first, we always want to give
- * preference to them. IDLE queues goes to the back.
- * after that, sort on the next service time.
- */
- if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
- n = &(*p)->rb_left;
- else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
- n = &(*p)->rb_right;
- else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
- n = &(*p)->rb_left;
- else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
- n = &(*p)->rb_right;
- else if (rb_key < __cfqq->rb_key)
- n = &(*p)->rb_left;
- else
- n = &(*p)->rb_right;
-
- if (n == &(*p)->rb_right)
- left = 0;
-
- p = n;
- }
-
- if (left)
- cfqd->service_tree.left = &cfqq->rb_node;
-
- cfqq->rb_key = rb_key;
- rb_link_node(&cfqq->rb_node, parent, p);
- rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
-}
-
static struct cfq_queue *
cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
sector_t sector, struct rb_node **ret_parent,
@@ -620,57 +395,34 @@ static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfqq->p_root = NULL;
}

-/*
- * Update cfqq's position in the service tree.
- */
-static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+/* An active ioq is being reset. A chance to do cic related stuff. */
+static void cfq_active_ioq_reset(struct request_queue *q, void *sched_queue)
{
- /*
- * Resorting requires the cfqq to be on the RR list already.
- */
- if (cfq_cfqq_on_rr(cfqq)) {
- cfq_service_tree_add(cfqd, cfqq, 0);
- cfq_prio_tree_add(cfqd, cfqq);
- }
-}
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_queue *cfqq = sched_queue;

-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
- BUG_ON(cfq_cfqq_on_rr(cfqq));
- cfq_mark_cfqq_on_rr(cfqq);
- cfqd->busy_queues++;
- if (cfq_class_rt(cfqq))
- cfqd->busy_rt_queues++;
+ if (cfqd->active_cic) {
+ put_io_context(cfqd->active_cic->ioc);
+ cfqd->active_cic = NULL;
+ }

- cfq_resort_rr_list(cfqd, cfqq);
+ /* Resort the cfqq in prio tree */
+ if (cfqq)
+ cfq_prio_tree_add(cfqd, cfqq);
}

-/*
- * Called when the cfqq no longer has requests pending, remove it from
- * the service tree.
- */
-static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+/* An ioq has been set as active one. */
+static void cfq_active_ioq_set(struct request_queue *q, void *sched_queue,
+ int coop)
{
- cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
- cfq_clear_cfqq_on_rr(cfqq);
+ struct cfq_queue *cfqq = sched_queue;

- if (!RB_EMPTY_NODE(&cfqq->rb_node))
- cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
- if (cfqq->p_root) {
- rb_erase(&cfqq->p_node, cfqq->p_root);
- cfqq->p_root = NULL;
- }
+ cfqq->slice_dispatch = 0;

- BUG_ON(!cfqd->busy_queues);
- cfqd->busy_queues--;
- if (cfq_class_rt(cfqq))
- cfqd->busy_rt_queues--;
+ cfq_clear_cfqq_must_alloc_slice(cfqq);
+ cfq_clear_cfqq_fifo_expire(cfqq);
+ if (!coop)
+ cfq_clear_cfqq_coop(cfqq);
}

/*
@@ -679,7 +431,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
static void cfq_del_rq_rb(struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
const int sync = rq_is_sync(rq);

BUG_ON(!cfqq->queued[sync]);
@@ -687,8 +438,17 @@ static void cfq_del_rq_rb(struct request *rq)

elv_rb_del(&cfqq->sort_list, rq);

- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
- cfq_del_cfqq_rr(cfqd, cfqq);
+ /*
+ * If this was last request in the queue, remove this queue from
+ * prio trees. For last request nr_queued count will still be 1 as
+ * elevator fair queuing layer is yet to do the accounting.
+ */
+ if (elv_ioq_nr_queued(cfqq->ioq) == 1) {
+ if (cfqq->p_root) {
+ rb_erase(&cfqq->p_node, cfqq->p_root);
+ cfqq->p_root = NULL;
+ }
+ }
}

static void cfq_add_rq_rb(struct request *rq)
@@ -706,9 +466,6 @@ static void cfq_add_rq_rb(struct request *rq)
while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
cfq_dispatch_insert(cfqd->queue, __alias);

- if (!cfq_cfqq_on_rr(cfqq))
- cfq_add_cfqq_rr(cfqd, cfqq);
-
/*
* check if this request is a better next-serve candidate
*/
@@ -756,23 +513,9 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;

- cfqd->rq_in_driver++;
- cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
- cfqd->rq_in_driver);
-
cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors;
}

-static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
- cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
- cfqd->rq_in_driver);
-}
-
static void cfq_remove_request(struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
@@ -783,7 +526,6 @@ static void cfq_remove_request(struct request *rq)
list_del_init(&rq->queuelist);
cfq_del_rq_rb(rq);

- cfqq->cfqd->rq_queued--;
if (rq_is_meta(rq)) {
WARN_ON(!cfqq->meta_pending);
cfqq->meta_pending--;
@@ -857,93 +599,21 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
return 0;
}

-static void __cfq_set_active_queue(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- if (cfqq) {
- cfq_log_cfqq(cfqd, cfqq, "set_active");
- cfqq->slice_end = 0;
- cfqq->slice_dispatch = 0;
-
- cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_must_alloc_slice(cfqq);
- cfq_clear_cfqq_fifo_expire(cfqq);
- cfq_mark_cfqq_slice_new(cfqq);
-
- del_timer(&cfqd->idle_slice_timer);
- }
-
- cfqd->active_queue = cfqq;
-}
-
/*
* current cfqq expired its slice (or was too idle), select new one
*/
static void
-__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int timed_out)
+__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
-
- if (cfq_cfqq_wait_request(cfqq))
- del_timer(&cfqd->idle_slice_timer);
-
- cfq_clear_cfqq_wait_request(cfqq);
-
- /*
- * store what was left of this slice, if the queue idled/timed out
- */
- if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
- cfqq->slice_resid = cfqq->slice_end - jiffies;
- cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
- }
-
- cfq_resort_rr_list(cfqd, cfqq);
-
- if (cfqq == cfqd->active_queue)
- cfqd->active_queue = NULL;
-
- if (cfqd->active_cic) {
- put_io_context(cfqd->active_cic->ioc);
- cfqd->active_cic = NULL;
- }
+ __elv_ioq_slice_expired(cfqd->queue, cfqq->ioq);
}

-static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
+static inline void cfq_slice_expired(struct cfq_data *cfqd)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
+ struct cfq_queue *cfqq = elv_active_sched_queue(cfqd->queue->elevator);

if (cfqq)
- __cfq_slice_expired(cfqd, cfqq, timed_out);
-}
-
-/*
- * Get next queue for service. Unless we have a queue preemption,
- * we'll simply select the first cfqq in the service tree.
- */
-static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
-{
- if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
- return NULL;
-
- return cfq_rb_first(&cfqd->service_tree);
-}
-
-/*
- * Get and set a new active queue for service.
- */
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
-{
- if (!cfqq) {
- cfqq = cfq_get_next_queue(cfqd);
- if (cfqq)
- cfq_clear_cfqq_coop(cfqq);
- }
-
- __cfq_set_active_queue(cfqd, cfqq);
- return cfqq;
+ __cfq_slice_expired(cfqd, cfqq);
}

static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
@@ -1020,11 +690,12 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
* associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
* assumption.
*/
-static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
- struct cfq_queue *cur_cfqq,
+static struct io_queue *cfq_close_cooperator(struct request_queue *q,
+ void *cur_sched_queue,
int probe)
{
- struct cfq_queue *cfqq;
+ struct cfq_queue *cur_cfqq = cur_sched_queue, *cfqq;
+ struct cfq_data *cfqd = q->elevator->elevator_data;

/*
* A valid cfq_io_context is necessary to compare requests against
@@ -1047,38 +718,18 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,

if (!probe)
cfq_mark_cfqq_coop(cfqq);
- return cfqq;
+ return cfqq->ioq;
}

-static void cfq_arm_slice_timer(struct cfq_data *cfqd)
+static void cfq_arm_slice_timer(struct request_queue *q, void *sched_queue)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_queue *cfqq = sched_queue;
struct cfq_io_context *cic;
unsigned long sl;

- /*
- * SSD device without seek penalty, disable idling. But only do so
- * for devices that support queuing, otherwise we still have a problem
- * with sync vs async workloads.
- */
- if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
- return;
-
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
- WARN_ON(cfq_cfqq_slice_new(cfqq));
-
- /*
- * idle is disabled, either manually or by past process history
- */
- if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
- return;
-
- /*
- * still requests with the driver, don't idle
- */
- if (cfqd->rq_in_driver)
- return;
-
+ WARN_ON(elv_ioq_slice_new(cfqq->ioq));
/*
* task has exited, don't wait
*/
@@ -1086,18 +737,18 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
if (!cic || !atomic_read(&cic->ioc->nr_tasks))
return;

- cfq_mark_cfqq_wait_request(cfqq);

+ elv_mark_ioq_wait_request(cfqq->ioq);
/*
* we don't want to idle for seeks, but we do want to allow
* fair distribution of slice time for a process doing back-to-back
* seeks. so allow a little bit of time for him to submit a new rq
*/
- sl = cfqd->cfq_slice_idle;
+ sl = elv_get_slice_idle(q->elevator);
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));

- mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
+ elv_mod_idle_slice_timer(q->elevator, jiffies + sl);
cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
}

@@ -1106,13 +757,12 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
*/
static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
+ struct cfq_data *cfqd = q->elevator->elevator_data;

- cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
+ cfq_log_cfqq(cfqd, cfqq, "dispatch_insert sect=%d", rq->nr_sectors);

cfq_remove_request(rq);
- cfqq->dispatched++;
elv_dispatch_sort(q, rq);

if (cfq_cfqq_sync(cfqq))
@@ -1150,78 +800,11 @@ static inline int
cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
const int base_rq = cfqd->cfq_slice_async_rq;
+ unsigned short ioprio = elv_ioq_ioprio(cfqq->ioq);

- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ WARN_ON(ioprio >= IOPRIO_BE_NR);

- return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
-}
-
-/*
- * Select a queue for service. If we have a current active queue,
- * check whether to continue servicing it, or retrieve and set a new one.
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
-{
- struct cfq_queue *cfqq, *new_cfqq = NULL;
-
- cfqq = cfqd->active_queue;
- if (!cfqq)
- goto new_queue;
-
- /*
- * The active queue has run out of time, expire it and select new.
- */
- if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
- goto expire;
-
- /*
- * If we have a RT cfqq waiting, then we pre-empt the current non-rt
- * cfqq.
- */
- if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
- /*
- * We simulate this as cfqq timed out so that it gets to bank
- * the remaining of its time slice.
- */
- cfq_log_cfqq(cfqd, cfqq, "preempt");
- cfq_slice_expired(cfqd, 1);
- goto new_queue;
- }
-
- /*
- * The active queue has requests and isn't expired, allow it to
- * dispatch.
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- goto keep_queue;
-
- /*
- * If another queue has a request waiting within our mean seek
- * distance, let it run. The expire code will check for close
- * cooperators and put the close queue at the front of the service
- * tree.
- */
- new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
- if (new_cfqq)
- goto expire;
-
- /*
- * No requests pending. If the active queue still has requests in
- * flight or is idling for a new request, allow either of these
- * conditions to happen (or time out) before selecting a new queue.
- */
- if (timer_pending(&cfqd->idle_slice_timer) ||
- (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
- cfqq = NULL;
- goto keep_queue;
- }
-
-expire:
- cfq_slice_expired(cfqd, 0);
-new_queue:
- cfqq = cfq_set_active_queue(cfqd, new_cfqq);
-keep_queue:
- return cfqq;
+ return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - ioprio));
}

static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
@@ -1246,12 +829,14 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
struct cfq_queue *cfqq;
int dispatched = 0;

- while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL)
+ while ((cfqq = elv_select_sched_queue(cfqd->queue, 1)) != NULL)
dispatched += __cfq_forced_dispatch_cfqq(cfqq);

- cfq_slice_expired(cfqd, 0);
+ /* This probably is redundant now. above loop will should make sure
+ * that all the busy queues have expired */
+ cfq_slice_expired(cfqd);

- BUG_ON(cfqd->busy_queues);
+ BUG_ON(elv_nr_busy_ioq(cfqd->queue->elevator));

cfq_log(cfqd, "forced_dispatch=%d\n", dispatched);
return dispatched;
@@ -1297,13 +882,10 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
struct cfq_queue *cfqq;
unsigned int max_dispatch;

- if (!cfqd->busy_queues)
- return 0;
-
if (unlikely(force))
return cfq_forced_dispatch(cfqd);

- cfqq = cfq_select_queue(cfqd);
+ cfqq = elv_select_sched_queue(q, 0);
if (!cfqq)
return 0;

@@ -1320,7 +902,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
/*
* Does this cfqq already have too much IO in flight?
*/
- if (cfqq->dispatched >= max_dispatch) {
+ if (elv_ioq_nr_dispatched(cfqq->ioq) >= max_dispatch) {
/*
* idle queue must always only have a single IO in flight
*/
@@ -1330,13 +912,13 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
/*
* We have other queues, don't allow more IO from this one
*/
- if (cfqd->busy_queues > 1)
+ if (elv_nr_busy_ioq(q->elevator) > 1)
return 0;

/*
* we are the only queue, allow up to 4 times of 'quantum'
*/
- if (cfqq->dispatched >= 4 * max_dispatch)
+ if (elv_ioq_nr_dispatched(cfqq->ioq) >= 4 * max_dispatch)
return 0;
}

@@ -1345,51 +927,45 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
*/
cfq_dispatch_request(cfqd, cfqq);
cfqq->slice_dispatch++;
- cfq_clear_cfqq_must_dispatch(cfqq);

/*
* expire an async queue immediately if it has used up its slice. idle
* queue always expire after 1 dispatch round.
*/
- if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
+ if (elv_nr_busy_ioq(q->elevator) > 1 && ((!cfq_cfqq_sync(cfqq) &&
cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
cfq_class_idle(cfqq))) {
- cfqq->slice_end = jiffies + 1;
- cfq_slice_expired(cfqd, 0);
+ cfq_slice_expired(cfqd);
}

cfq_log(cfqd, "dispatched a request");
return 1;
}

-/*
- * task holds one reference to the queue, dropped when task exits. each rq
- * in-flight on this queue also holds a reference, dropped when rq is freed.
- *
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
+static void cfq_free_cfq_queue(struct elevator_queue *e, void *sched_queue)
{
+ struct cfq_queue *cfqq = sched_queue;
struct cfq_data *cfqd = cfqq->cfqd;

- BUG_ON(atomic_read(&cfqq->ref) <= 0);
-
- if (!atomic_dec_and_test(&cfqq->ref))
- return;
+ BUG_ON(!cfqq);

- cfq_log_cfqq(cfqd, cfqq, "put_queue");
+ cfq_log_cfqq(cfqd, cfqq, "free_queue");
BUG_ON(rb_first(&cfqq->sort_list));
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
- BUG_ON(cfq_cfqq_on_rr(cfqq));

- if (unlikely(cfqd->active_queue == cfqq)) {
- __cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
+ if (unlikely(cfqq_is_active_queue(cfqq))) {
+ __cfq_slice_expired(cfqd, cfqq);
+ elv_schedule_dispatch(cfqd->queue);
}

kmem_cache_free(cfq_pool, cfqq);
}

+static inline void cfq_put_queue(struct cfq_queue *cfqq)
+{
+ elv_put_ioq(cfqq->ioq);
+}
+
/*
* Must always be called with the rcu_read_lock() held
*/
@@ -1477,9 +1053,9 @@ static void cfq_free_io_context(struct io_context *ioc)

static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- if (unlikely(cfqq == cfqd->active_queue)) {
- __cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
+ if (unlikely(cfqq == elv_active_sched_queue(cfqd->queue->elevator))) {
+ __cfq_slice_expired(cfqd, cfqq);
+ elv_schedule_dispatch(cfqd->queue);
}

cfq_put_queue(cfqq);
@@ -1549,11 +1125,11 @@ static struct cfq_io_context *
cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
{
struct cfq_io_context *cic;
+ struct request_queue *q = cfqd->queue;

cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
- cfqd->queue->node);
+ q->node);
if (cic) {
- cic->last_end_request = jiffies;
INIT_LIST_HEAD(&cic->queue_list);
INIT_HLIST_NODE(&cic->cic_list);
cic->dtor = cfq_free_io_context;
@@ -1567,7 +1143,7 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
{
struct task_struct *tsk = current;
- int ioprio_class;
+ int ioprio_class, ioprio;

if (!cfq_cfqq_prio_changed(cfqq))
return;
@@ -1580,30 +1156,33 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
/*
* no prio set, inherit CPU scheduling settings
*/
- cfqq->ioprio = task_nice_ioprio(tsk);
- cfqq->ioprio_class = task_nice_ioclass(tsk);
+ ioprio = task_nice_ioprio(tsk);
+ ioprio_class = task_nice_ioclass(tsk);
break;
case IOPRIO_CLASS_RT:
- cfqq->ioprio = task_ioprio(ioc);
- cfqq->ioprio_class = IOPRIO_CLASS_RT;
+ ioprio = task_ioprio(ioc);
+ ioprio_class = IOPRIO_CLASS_RT;
break;
case IOPRIO_CLASS_BE:
- cfqq->ioprio = task_ioprio(ioc);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
+ ioprio = task_ioprio(ioc);
+ ioprio_class = IOPRIO_CLASS_BE;
break;
case IOPRIO_CLASS_IDLE:
- cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
- cfqq->ioprio = 7;
- cfq_clear_cfqq_idle_window(cfqq);
+ ioprio_class = IOPRIO_CLASS_IDLE;
+ ioprio = 7;
+ elv_clear_ioq_idle_window(cfqq->ioq);
break;
}

+ elv_ioq_set_ioprio_class(cfqq->ioq, ioprio_class);
+ elv_ioq_set_ioprio(cfqq->ioq, ioprio);
+
/*
* keep track of original prio settings in case we have to temporarily
* elevate the priority of this queue
*/
- cfqq->org_ioprio = cfqq->ioprio;
- cfqq->org_ioprio_class = cfqq->ioprio_class;
+ cfqq->org_ioprio = ioprio;
+ cfqq->org_ioprio_class = ioprio_class;
cfq_clear_cfqq_prio_changed(cfqq);
}

@@ -1612,11 +1191,12 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
struct cfq_data *cfqd = cic->key;
struct cfq_queue *cfqq;
unsigned long flags;
+ struct request_queue *q = cfqd->queue;

if (unlikely(!cfqd))
return;

- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+ spin_lock_irqsave(q->queue_lock, flags);

cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) {
@@ -1633,7 +1213,7 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);

- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ spin_unlock_irqrestore(q->queue_lock, flags);
}

static void cfq_ioc_set_ioprio(struct io_context *ioc)
@@ -1644,11 +1224,12 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)

static struct cfq_queue *
cfq_find_alloc_queue(struct cfq_data *cfqd, int 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_io_context *cic;
-
+ struct request_queue *q = cfqd->queue;
+ struct io_queue *ioq = NULL, *new_ioq = NULL;
retry:
cic = cfq_cic_lookup(cfqd, ioc);
/* cic always exists here */
@@ -1656,8 +1237,7 @@ retry:

if (!cfqq) {
if (new_cfqq) {
- cfqq = new_cfqq;
- new_cfqq = NULL;
+ goto alloc_ioq;
} else if (gfp_mask & __GFP_WAIT) {
/*
* Inform the allocator of the fact that we will
@@ -1678,22 +1258,52 @@ retry:
if (!cfqq)
goto out;
}
+alloc_ioq:
+ if (new_ioq) {
+ ioq = new_ioq;
+ new_ioq = NULL;
+ cfqq = new_cfqq;
+ new_cfqq = NULL;
+ } else if (gfp_mask & __GFP_WAIT) {
+ /*
+ * Inform the allocator of the fact that we will
+ * just repeat this allocation if it fails, to allow
+ * the allocator to do whatever it needs to attempt to
+ * free memory.
+ */
+ spin_unlock_irq(q->queue_lock);
+ new_ioq = elv_alloc_ioq(q,
+ gfp_mask | __GFP_NOFAIL | __GFP_ZERO);
+ spin_lock_irq(q->queue_lock);
+ goto retry;
+ } else {
+ ioq = elv_alloc_ioq(q, gfp_mask | __GFP_ZERO);
+ if (!ioq) {
+ kmem_cache_free(cfq_pool, cfqq);
+ cfqq = NULL;
+ goto out;
+ }
+ }

- RB_CLEAR_NODE(&cfqq->rb_node);
+ /*
+ * Both cfqq and ioq objects allocated. Do the initializations
+ * now.
+ */
RB_CLEAR_NODE(&cfqq->p_node);
INIT_LIST_HEAD(&cfqq->fifo);
-
- atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;

cfq_mark_cfqq_prio_changed(cfqq);

+ cfqq->ioq = ioq;
cfq_init_prio_data(cfqq, ioc);
+ elv_init_ioq(q->elevator, ioq, cfqq, cfqq->org_ioprio_class,
+ cfqq->org_ioprio, is_sync);

if (is_sync) {
if (!cfq_class_idle(cfqq))
- cfq_mark_cfqq_idle_window(cfqq);
- cfq_mark_cfqq_sync(cfqq);
+ elv_mark_ioq_idle_window(cfqq->ioq);
+ elv_mark_ioq_sync(cfqq->ioq);
}
cfqq->pid = current->pid;
cfq_log_cfqq(cfqd, cfqq, "alloced");
@@ -1702,38 +1312,28 @@ retry:
if (new_cfqq)
kmem_cache_free(cfq_pool, new_cfqq);

+ if (new_ioq)
+ elv_free_ioq(new_ioq);
+
out:
WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
return cfqq;
}

-static struct cfq_queue **
-cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
-{
- switch (ioprio_class) {
- case IOPRIO_CLASS_RT:
- return &cfqd->async_cfqq[0][ioprio];
- case IOPRIO_CLASS_BE:
- return &cfqd->async_cfqq[1][ioprio];
- case IOPRIO_CLASS_IDLE:
- return &cfqd->async_idle_cfqq;
- default:
- BUG();
- }
-}
-
static struct cfq_queue *
cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc,
- gfp_t gfp_mask)
+ gfp_t gfp_mask)
{
const int ioprio = task_ioprio(ioc);
const int ioprio_class = task_ioprio_class(ioc);
- struct cfq_queue **async_cfqq = NULL;
+ struct cfq_queue *async_cfqq = NULL;
struct cfq_queue *cfqq = NULL;
+ struct io_group *iog = io_lookup_io_group_current(cfqd->queue);

if (!is_sync) {
- async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
- cfqq = *async_cfqq;
+ async_cfqq = io_group_async_queue_prio(iog, ioprio_class,
+ ioprio);
+ cfqq = async_cfqq;
}

if (!cfqq) {
@@ -1742,15 +1342,11 @@ cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc,
return NULL;
}

- /*
- * pin the queue now that it's allocated, scheduler exit will prune it
- */
- if (!is_sync && !(*async_cfqq)) {
- atomic_inc(&cfqq->ref);
- *async_cfqq = cfqq;
- }
+ if (!is_sync && !async_cfqq)
+ io_group_set_async_queue(iog, ioprio_class, ioprio, cfqq->ioq);

- atomic_inc(&cfqq->ref);
+ /* ioc reference */
+ elv_get_ioq(cfqq->ioq);
return cfqq;
}

@@ -1829,6 +1425,7 @@ static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
{
unsigned long flags;
int ret;
+ struct request_queue *q = cfqd->queue;

ret = radix_tree_preload(gfp_mask);
if (!ret) {
@@ -1845,9 +1442,9 @@ static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
radix_tree_preload_end();

if (!ret) {
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+ spin_lock_irqsave(q->queue_lock, flags);
list_add(&cic->queue_list, &cfqd->cic_list);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
}

@@ -1867,10 +1464,11 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
{
struct io_context *ioc = NULL;
struct cfq_io_context *cic;
+ struct request_queue *q = cfqd->queue;

might_sleep_if(gfp_mask & __GFP_WAIT);

- ioc = get_io_context(gfp_mask, cfqd->queue->node);
+ ioc = get_io_context(gfp_mask, q->node);
if (!ioc)
return NULL;

@@ -1889,7 +1487,6 @@ out:
smp_read_barrier_depends();
if (unlikely(ioc->ioprio_changed))
cfq_ioc_set_ioprio(ioc);
-
return cic;
err_free:
cfq_cic_free(cic);
@@ -1899,17 +1496,6 @@ err:
}

static void
-cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
-{
- unsigned long elapsed = jiffies - cic->last_end_request;
- unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
-
- cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
- cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
- cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
-}
-
-static void
cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
struct request *rq)
{
@@ -1940,57 +1526,41 @@ cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
}

/*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter
+ * Disable idle window if the process seeks so much that it doesn't matter
*/
-static void
-cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
+static int
+cfq_update_idle_window(struct elevator_queue *eq, void *cfqq,
+ struct request *rq)
{
- int old_idle, enable_idle;
+ struct cfq_io_context *cic = RQ_CIC(rq);

/*
- * Don't idle for async or idle io prio class
+ * Enabling/Disabling idling based on thinktime has been moved
+ * in common layer.
*/
- if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
- return;
-
- enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
-
- if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (cfqd->hw_tag && CIC_SEEKY(cic)))
- enable_idle = 0;
- else if (sample_valid(cic->ttime_samples)) {
- if (cic->ttime_mean > cfqd->cfq_slice_idle)
- enable_idle = 0;
- else
- enable_idle = 1;
- }
+ if (!atomic_read(&cic->ioc->nr_tasks) ||
+ (elv_hw_tag(eq) && CIC_SEEKY(cic)))
+ return 0;

- if (old_idle != enable_idle) {
- cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
- if (enable_idle)
- cfq_mark_cfqq_idle_window(cfqq);
- else
- cfq_clear_cfqq_idle_window(cfqq);
- }
+ return 1;
}

/*
* Check if new_cfqq should preempt the currently active queue. Return 0 for
- * no or if we aren't sure, a 1 will cause a preempt.
+ * no or if we aren't sure, a 1 will cause a preemption attempt.
+ * Some of the preemption logic has been moved to common layer. Only cfq
+ * specific parts are left here.
*/
static int
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
- struct request *rq)
+cfq_should_preempt(struct request_queue *q, void *new_cfqq, struct request *rq)
{
- struct cfq_queue *cfqq;
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_queue *cfqq = elv_active_sched_queue(q->elevator);

- cfqq = cfqd->active_queue;
if (!cfqq)
return 0;

- if (cfq_slice_used(cfqq))
+ if (elv_ioq_slice_used(cfqq->ioq))
return 1;

if (cfq_class_idle(new_cfqq))
@@ -2013,13 +1583,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (rq_is_meta(rq) && !cfqq->meta_pending)
return 1;

- /*
- * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
- */
- if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
- return 1;
-
- if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+ if (!cfqd->active_cic || !elv_ioq_wait_request(cfqq->ioq))
return 0;

/*
@@ -2033,29 +1597,10 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
}

/*
- * cfqq preempts the active queue. if we allowed preempt with no slice left,
- * let it have half of its nominal slice.
- */
-static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- cfq_log_cfqq(cfqd, cfqq, "preempt");
- cfq_slice_expired(cfqd, 1);
-
- /*
- * Put the new queue at the front of the of the current list,
- * so we know that it will be selected next.
- */
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
- cfq_service_tree_add(cfqd, cfqq, 1);
-
- cfqq->slice_end = 0;
- cfq_mark_cfqq_slice_new(cfqq);
-}
-
-/*
* Called when a new fs request (rq) is added (to cfqq). Check if there's
* something we should do about it
+ * After enqueuing the request whether queue should be preempted or kicked
+ * decision is taken by common layer.
*/
static void
cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
@@ -2063,45 +1608,12 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
{
struct cfq_io_context *cic = RQ_CIC(rq);

- cfqd->rq_queued++;
if (rq_is_meta(rq))
cfqq->meta_pending++;

- cfq_update_io_thinktime(cfqd, cic);
cfq_update_io_seektime(cfqd, cic, rq);
- cfq_update_idle_window(cfqd, cfqq, cic);

cic->last_request_pos = rq->sector + rq->nr_sectors;
-
- if (cfqq == cfqd->active_queue) {
- /*
- * Remember that we saw a request from this process, but
- * don't start queuing just yet. Otherwise we risk seeing lots
- * of tiny requests, because we disrupt the normal plugging
- * and merging. If the request is already larger than a single
- * page, let it rip immediately. For that case we assume that
- * merging is already done. Ditto for a busy system that
- * has other work pending, don't risk delaying until the
- * idle timer unplug to continue working.
- */
- if (cfq_cfqq_wait_request(cfqq)) {
- if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
- cfqd->busy_queues > 1) {
- del_timer(&cfqd->idle_slice_timer);
- blk_start_queueing(cfqd->queue);
- }
- cfq_mark_cfqq_must_dispatch(cfqq);
- }
- } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
- /*
- * not the active queue - expire current slice if it is
- * idle and has expired it's mean thinktime or this new queue
- * has some old slice time left and is of higher priority or
- * this new queue is RT and the current one is BE
- */
- cfq_preempt_queue(cfqd, cfqq);
- blk_start_queueing(cfqd->queue);
- }
}

static void cfq_insert_request(struct request_queue *q, struct request *rq)
@@ -2119,84 +1631,17 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
cfq_rq_enqueued(cfqd, cfqq, rq);
}

-/*
- * Update hw_tag based on peak queue depth over 50 samples under
- * sufficient load.
- */
-static void cfq_update_hw_tag(struct cfq_data *cfqd)
-{
- if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
- cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
-
- if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
- cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
- return;
-
- if (cfqd->hw_tag_samples++ < 50)
- return;
-
- if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN)
- cfqd->hw_tag = 1;
- else
- cfqd->hw_tag = 0;
-
- cfqd->hw_tag_samples = 0;
- cfqd->rq_in_driver_peak = 0;
-}
-
static void cfq_completed_request(struct request_queue *q, struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = rq_is_sync(rq);
unsigned long now;

now = jiffies;
cfq_log_cfqq(cfqd, cfqq, "complete");

- cfq_update_hw_tag(cfqd);
-
- WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->dispatched);
- cfqd->rq_in_driver--;
- cfqq->dispatched--;
-
if (cfq_cfqq_sync(cfqq))
cfqd->sync_flight--;
-
- if (!cfq_class_idle(cfqq))
- cfqd->last_end_request = now;
-
- if (sync)
- RQ_CIC(rq)->last_end_request = now;
-
- /*
- * If this is the active queue, check if it needs to be expired,
- * or if we want to idle in case it has no pending requests.
- */
- if (cfqd->active_queue == cfqq) {
- const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
-
- if (cfq_cfqq_slice_new(cfqq)) {
- cfq_set_prio_slice(cfqd, cfqq);
- cfq_clear_cfqq_slice_new(cfqq);
- }
- /*
- * If there are no requests waiting in this queue, and
- * there are other queues ready to issue requests, AND
- * those other queues are issuing requests within our
- * mean seek distance, give them a chance to run instead
- * of idling.
- */
- if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
- cfq_slice_expired(cfqd, 1);
- else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
- sync && !rq_noidle(rq))
- cfq_arm_slice_timer(cfqd);
- }
-
- if (!cfqd->rq_in_driver)
- cfq_schedule_dispatch(cfqd);
}

/*
@@ -2205,30 +1650,33 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
*/
static void cfq_prio_boost(struct cfq_queue *cfqq)
{
+ struct io_queue *ioq = cfqq->ioq;
+
if (has_fs_excl()) {
/*
* boost idle prio on transactions that would lock out other
* users of the filesystem
*/
if (cfq_class_idle(cfqq))
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- if (cfqq->ioprio > IOPRIO_NORM)
- cfqq->ioprio = IOPRIO_NORM;
+ elv_ioq_set_ioprio_class(ioq, IOPRIO_CLASS_BE);
+ if (elv_ioq_ioprio(ioq) > IOPRIO_NORM)
+ elv_ioq_set_ioprio(ioq, IOPRIO_NORM);
+
} else {
/*
* check if we need to unboost the queue
*/
- if (cfqq->ioprio_class != cfqq->org_ioprio_class)
- cfqq->ioprio_class = cfqq->org_ioprio_class;
- if (cfqq->ioprio != cfqq->org_ioprio)
- cfqq->ioprio = cfqq->org_ioprio;
+ if (elv_ioq_ioprio_class(ioq) != cfqq->org_ioprio_class)
+ elv_ioq_set_ioprio_class(ioq, cfqq->org_ioprio_class);
+ if (elv_ioq_ioprio(ioq) != cfqq->org_ioprio)
+ elv_ioq_set_ioprio(ioq, cfqq->org_ioprio);
}
}

static inline int __cfq_may_queue(struct cfq_queue *cfqq)
{
- if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
- !cfq_cfqq_must_alloc_slice(cfqq)) {
+ if ((elv_ioq_wait_request(cfqq->ioq) ||
+ cfq_cfqq_must_alloc(cfqq)) && !cfq_cfqq_must_alloc_slice(cfqq)) {
cfq_mark_cfqq_must_alloc_slice(cfqq);
return ELV_MQUEUE_MUST;
}
@@ -2280,7 +1728,7 @@ static void cfq_put_request(struct request *rq)
put_io_context(RQ_CIC(rq)->ioc);

rq->elevator_private = NULL;
- rq->elevator_private2 = NULL;
+ rq->ioq = NULL;

cfq_put_queue(cfqq);
}
@@ -2320,119 +1768,31 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)

cfqq->allocated[rw]++;
cfq_clear_cfqq_must_alloc(cfqq);
- atomic_inc(&cfqq->ref);
+ elv_get_ioq(cfqq->ioq);

spin_unlock_irqrestore(q->queue_lock, flags);

rq->elevator_private = cic;
- rq->elevator_private2 = cfqq;
+ rq->ioq = cfqq->ioq;
return 0;

queue_fail:
if (cic)
put_io_context(cic->ioc);

- cfq_schedule_dispatch(cfqd);
+ elv_schedule_dispatch(cfqd->queue);
spin_unlock_irqrestore(q->queue_lock, flags);
cfq_log(cfqd, "set_request fail");
return 1;
}

-static void cfq_kick_queue(struct work_struct *work)
-{
- struct cfq_data *cfqd =
- container_of(work, struct cfq_data, unplug_work);
- struct request_queue *q = cfqd->queue;
-
- spin_lock_irq(q->queue_lock);
- blk_start_queueing(q);
- spin_unlock_irq(q->queue_lock);
-}
-
-/*
- * Timer running if the active_queue is currently idling inside its time slice
- */
-static void cfq_idle_slice_timer(unsigned long data)
-{
- struct cfq_data *cfqd = (struct cfq_data *) data;
- struct cfq_queue *cfqq;
- unsigned long flags;
- int timed_out = 1;
-
- cfq_log(cfqd, "idle timer fired");
-
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
- cfqq = cfqd->active_queue;
- if (cfqq) {
- timed_out = 0;
-
- /*
- * We saw a request before the queue expired, let it through
- */
- if (cfq_cfqq_must_dispatch(cfqq))
- goto out_kick;
-
- /*
- * expired
- */
- if (cfq_slice_used(cfqq))
- goto expire;
-
- /*
- * only expire and reinvoke request handler, if there are
- * other queues with pending requests
- */
- if (!cfqd->busy_queues)
- goto out_cont;
-
- /*
- * not expired and it has a request pending, let it dispatch
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- goto out_kick;
- }
-expire:
- cfq_slice_expired(cfqd, timed_out);
-out_kick:
- cfq_schedule_dispatch(cfqd);
-out_cont:
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
-{
- del_timer_sync(&cfqd->idle_slice_timer);
- cancel_work_sync(&cfqd->unplug_work);
-}
-
-static void cfq_put_async_queues(struct cfq_data *cfqd)
-{
- int i;
-
- for (i = 0; i < IOPRIO_BE_NR; i++) {
- if (cfqd->async_cfqq[0][i])
- cfq_put_queue(cfqd->async_cfqq[0][i]);
- if (cfqd->async_cfqq[1][i])
- cfq_put_queue(cfqd->async_cfqq[1][i]);
- }
-
- if (cfqd->async_idle_cfqq)
- cfq_put_queue(cfqd->async_idle_cfqq);
-}
-
static void cfq_exit_queue(struct elevator_queue *e)
{
struct cfq_data *cfqd = e->elevator_data;
struct request_queue *q = cfqd->queue;

- cfq_shutdown_timer_wq(cfqd);
-
spin_lock_irq(q->queue_lock);

- 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,
@@ -2441,12 +1801,7 @@ static void cfq_exit_queue(struct elevator_queue *e)
__cfq_exit_single_io_context(cfqd, cic);
}

- cfq_put_async_queues(cfqd);
-
spin_unlock_irq(q->queue_lock);
-
- cfq_shutdown_timer_wq(cfqd);
-
kfree(cfqd);
}

@@ -2459,8 +1814,6 @@ static void *cfq_init_queue(struct request_queue *q)
if (!cfqd)
return NULL;

- cfqd->service_tree = CFQ_RB_ROOT;
-
/*
* Not strictly needed (since RB_ROOT just clears the node and we
* zeroed cfqd on alloc), but better be safe in case someone decides
@@ -2473,23 +1826,12 @@ static void *cfq_init_queue(struct request_queue *q)

cfqd->queue = q;

- init_timer(&cfqd->idle_slice_timer);
- cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
- cfqd->idle_slice_timer.data = (unsigned long) cfqd;
-
- INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
-
- cfqd->last_end_request = jiffies;
cfqd->cfq_quantum = cfq_quantum;
cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
cfqd->cfq_back_max = cfq_back_max;
cfqd->cfq_back_penalty = cfq_back_penalty;
- cfqd->cfq_slice[0] = cfq_slice_async;
- cfqd->cfq_slice[1] = cfq_slice_sync;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
- cfqd->cfq_slice_idle = cfq_slice_idle;
- cfqd->hw_tag = 1;

return cfqd;
}
@@ -2554,9 +1896,6 @@ SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0);
-SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
-SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
-SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
#undef SHOW_FUNCTION

@@ -2584,9 +1923,6 @@ STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1,
STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1,
UINT_MAX, 0);
-STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
UINT_MAX, 0);
#undef STORE_FUNCTION
@@ -2600,10 +1936,10 @@ static struct elv_fs_entry cfq_attrs[] = {
CFQ_ATTR(fifo_expire_async),
CFQ_ATTR(back_seek_max),
CFQ_ATTR(back_seek_penalty),
- CFQ_ATTR(slice_sync),
- CFQ_ATTR(slice_async),
CFQ_ATTR(slice_async_rq),
- CFQ_ATTR(slice_idle),
+ ELV_ATTR(slice_idle),
+ ELV_ATTR(slice_sync),
+ ELV_ATTR(slice_async),
__ATTR_NULL
};

@@ -2616,8 +1952,6 @@ static struct elevator_type iosched_cfq = {
.elevator_dispatch_fn = cfq_dispatch_requests,
.elevator_add_req_fn = cfq_insert_request,
.elevator_activate_req_fn = cfq_activate_request,
- .elevator_deactivate_req_fn = cfq_deactivate_request,
- .elevator_queue_empty_fn = cfq_queue_empty,
.elevator_completed_req_fn = cfq_completed_request,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
@@ -2627,7 +1961,15 @@ static struct elevator_type iosched_cfq = {
.elevator_init_fn = cfq_init_queue,
.elevator_exit_fn = cfq_exit_queue,
.trim = cfq_free_io_context,
+ .elevator_free_sched_queue_fn = cfq_free_cfq_queue,
+ .elevator_active_ioq_set_fn = cfq_active_ioq_set,
+ .elevator_active_ioq_reset_fn = cfq_active_ioq_reset,
+ .elevator_arm_slice_timer_fn = cfq_arm_slice_timer,
+ .elevator_should_preempt_fn = cfq_should_preempt,
+ .elevator_update_idle_window_fn = cfq_update_idle_window,
+ .elevator_close_cooperator_fn = cfq_close_cooperator,
},
+ .elevator_features = ELV_IOSCHED_NEED_FQ,
.elevator_attrs = cfq_attrs,
.elevator_name = "cfq",
.elevator_owner = THIS_MODULE,
@@ -2635,14 +1977,6 @@ static struct elevator_type iosched_cfq = {

static int __init cfq_init(void)
{
- /*
- * could be 0 on HZ < 1000 setups
- */
- if (!cfq_slice_async)
- cfq_slice_async = 1;
- if (!cfq_slice_idle)
- cfq_slice_idle = 1;
-
if (cfq_slab_setup())
return -ENOMEM;

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 08b987b..5be25b3 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -39,13 +39,8 @@ struct cfq_io_context {

struct io_context *ioc;

- unsigned long last_end_request;
sector_t last_request_pos;

- unsigned long ttime_total;
- unsigned long ttime_samples;
- unsigned long ttime_mean;
-
unsigned int seek_samples;
u64 seek_total;
sector_t seek_mean;
--
1.6.0.6