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提交 07e44708 编写于 作者: J Jens Axboe
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Merge branch 'cfq' into for-linus

上级 2a12dcd7 597bc485
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Showing with 439 addition and 416 deletion
block/cfq-iosched.c
浏览文件 @ 07e44708
......@@ -9,7 +9,6 @@
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
......@@ -26,19 +25,17 @@ static int cfq_slice_async = HZ / 25;
static const int cfq_slice_async_rq = 2;
static int cfq_slice_idle = HZ / 125;
/*
* grace period before allowing idle class to get disk access
*/
#define CFQ_IDLE_GRACE (HZ / 10)
#define CFQ_SLICE_SCALE (5)
#define CFQ_KEY_ASYNC (0)
/*
* for the hash of cfqq inside the cfqd
* below this threshold, we consider thinktime immediate
*/
#define CFQ_QHASH_SHIFT 6
#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
#define CFQ_MIN_TT (2)
#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
#define CFQ_SLICE_SCALE (5)
#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
#define RQ_CFQQ(rq) ((rq)->elevator_private2)
......@@ -56,16 +53,20 @@ static struct completion *ioc_gone;
#define ASYNC (0)
#define SYNC (1)
#define cfq_cfqq_dispatched(cfqq) \
((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
#define cfq_cfqq_sync(cfqq) \
(cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
#define sample_valid(samples) ((samples) > 80)
/*
* 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
* to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
* move this into the elevator for the rq sorting as well.
*/
struct cfq_rb_root {
struct rb_root rb;
struct rb_node *left;
};
#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, }
/*
* Per block device queue structure
*/
......@@ -75,18 +76,11 @@ struct cfq_data {
/*
* rr list of queues with requests and the count of them
*/
struct list_head rr_list[CFQ_PRIO_LISTS];
struct list_head busy_rr;
struct list_head cur_rr;
struct list_head idle_rr;
struct cfq_rb_root service_tree;
unsigned int busy_queues;
/*
* cfqq lookup hash
*/
struct hlist_head *cfq_hash;
int rq_in_driver;
int sync_flight;
int hw_tag;
/*
......@@ -97,12 +91,10 @@ struct cfq_data {
struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;
int cur_prio, cur_end_prio;
unsigned int dispatch_slice;
struct timer_list idle_class_timer;
sector_t last_sector;
sector_t last_position;
unsigned long last_end_request;
/*
......@@ -117,6 +109,9 @@ struct cfq_data {
unsigned int cfq_slice_idle;
struct list_head cic_list;
sector_t new_seek_mean;
u64 new_seek_total;
};
/*
......@@ -127,12 +122,10 @@ struct cfq_queue {
atomic_t ref;
/* parent cfq_data */
struct cfq_data *cfqd;
/* cfqq lookup hash */
struct hlist_node cfq_hash;
/* hash key */
unsigned int key;
/* member of the rr/busy/cur/idle cfqd list */
struct list_head cfq_list;
/* service_tree member */
struct rb_node rb_node;
/* service_tree key */
unsigned long rb_key;
/* sorted list of pending requests */
struct rb_root sort_list;
/* if fifo isn't expired, next request to serve */
......@@ -147,11 +140,10 @@ struct cfq_queue {
struct list_head fifo;
unsigned long slice_end;
unsigned long service_last;
long slice_resid;
/* number of requests that are on the dispatch list */
int on_dispatch[2];
/* number of requests that are on the dispatch list or inside driver */
int dispatched;
/* io prio of this group */
unsigned short ioprio, org_ioprio;
......@@ -159,6 +151,8 @@ struct cfq_queue {
/* various state flags, see below */
unsigned int flags;
sector_t last_request_pos;
};
enum cfqq_state_flags {
......@@ -172,6 +166,7 @@ enum cfqq_state_flags {
CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */
CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
CFQ_CFQQ_FLAG_sync, /* synchronous queue */
};
#define CFQ_CFQQ_FNS(name) \
......@@ -198,11 +193,38 @@ CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
CFQ_CFQQ_FNS(queue_new);
CFQ_CFQQ_FNS(slice_new);
CFQ_CFQQ_FNS(sync);
#undef CFQ_CFQQ_FNS
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
static void cfq_dispatch_insert(request_queue_t *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
struct task_struct *, gfp_t);
static struct cfq_io_context *cfq_cic_rb_lookup(struct cfq_data *,
struct io_context *);
static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
int is_sync)
{
return cic->cfqq[!!is_sync];
}
static inline void cic_set_cfqq(struct cfq_io_context *cic,
struct cfq_queue *cfqq, int is_sync)
{
cic->cfqq[!!is_sync] = cfqq;
}
/*
* We regard a request as SYNC, if it's either a read or has the SYNC bit
* set (in which case it could also be direct WRITE).
*/
static inline int cfq_bio_sync(struct bio *bio)
{
if (bio_data_dir(bio) == READ || bio_sync(bio))
return 1;
return 0;
}
/*
* scheduler run of queue, if there are requests pending and no one in the
......@@ -221,44 +243,31 @@ static int cfq_queue_empty(request_queue_t *q)
return !cfqd->busy_queues;
}
static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
{
/*
* Use the per-process queue, for read requests and syncronous writes
*/
if (!(rw & REQ_RW) || is_sync)
return task->pid;
return CFQ_KEY_ASYNC;
}
/*
* 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_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync,
unsigned short prio)
{
const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
const int base_slice = cfqd->cfq_slice[sync];
WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
WARN_ON(prio >= IOPRIO_BE_NR);
return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
}
return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
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)
{
cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
cfqq->slice_end += cfqq->slice_resid;
/*
* Don't carry over residual for more than one slice, we only want
* to slightly correct the fairness. Carrying over forever would
* easily introduce oscillations.
*/
cfqq->slice_resid = 0;
}
/*
......@@ -307,7 +316,7 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
s1 = rq1->sector;
s2 = rq2->sector;
last = cfqd->last_sector;
last = cfqd->last_position;
/*
* by definition, 1KiB is 2 sectors
......@@ -371,6 +380,26 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
}
}
/*
* The below is leftmost cache rbtree addon
*/
static struct rb_node *cfq_rb_first(struct cfq_rb_root *root)
{
if (!root->left)
root->left = rb_first(&root->rb);
return root->left;
}
static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
{
if (root->left == n)
root->left = NULL;
rb_erase(n, &root->rb);
RB_CLEAR_NODE(n);
}
/*
* would be nice to take fifo expire time into account as well
*/
......@@ -398,78 +427,96 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
return cfq_choose_req(cfqd, next, prev);
}
static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
struct cfq_queue *cfqq)
{
struct cfq_data *cfqd = cfqq->cfqd;
struct list_head *list, *n;
struct cfq_queue *__cfqq;
/*
* Resorting requires the cfqq to be on the RR list already.
* just an approximation, should be ok.
*/
if (!cfq_cfqq_on_rr(cfqq))
return;
return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
}
list_del(&cfqq->cfq_list);
/*
* 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 = &cfqd->service_tree.rb.rb_node;
struct rb_node *parent = NULL;
unsigned long rb_key;
int left;
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 (cfq_class_rt(cfqq))
list = &cfqd->cur_rr;
else if (cfq_class_idle(cfqq))
list = &cfqd->idle_rr;
else {
if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
/*
* if cfqq has requests in flight, don't allow it to be
* found in cfq_set_active_queue before it has finished them.
* this is done to increase fairness between a process that
* has lots of io pending vs one that only generates one
* sporadically or synchronously
* same position, nothing more to do
*/
if (cfq_cfqq_dispatched(cfqq))
list = &cfqd->busy_rr;
else
list = &cfqd->rr_list[cfqq->ioprio];
if (rb_key == cfqq->rb_key)
return;
cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
}
if (preempted || cfq_cfqq_queue_new(cfqq)) {
/*
* If this queue was preempted or is new (never been serviced),
* let it be added first for fairness but beind other new
* queues.
*/
n = list;
while (n->next != list) {
__cfqq = list_entry_cfqq(n->next);
if (!cfq_cfqq_queue_new(__cfqq))
break;
left = 1;
while (*p) {
struct cfq_queue *__cfqq;
struct rb_node **n;
parent = *p;
__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
n = n->next;
}
list_add_tail(&cfqq->cfq_list, n);
} else if (!cfq_cfqq_class_sync(cfqq)) {
/*
* async queue always goes to the end. this wont be overly
* unfair to writes, as the sort of the sync queue wont be
* allowed to pass the async queue again.
*/
list_add_tail(&cfqq->cfq_list, list);
} else {
/*
* sort by last service, but don't cross a new or async
* queue. we don't cross a new queue because it hasn't been
* service before, and we don't cross an async queue because
* it gets added to the end on expire.
* 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.
*/
n = list;
while ((n = n->prev) != list) {
struct cfq_queue *__cfqq = list_entry_cfqq(n);
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 (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
break;
if (time_before(__cfqq->service_last, cfqq->service_last))
break;
}
list_add(&cfqq->cfq_list, n);
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);
}
/*
* Update cfqq's position in the service tree.
*/
static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
/*
* Resorting requires the cfqq to be on the RR list already.
*/
if (cfq_cfqq_on_rr(cfqq))
cfq_service_tree_add(cfqd, cfqq, 0);
}
/*
......@@ -483,15 +530,21 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
cfq_resort_rr_list(cfqq, 0);
cfq_resort_rr_list(cfqd, cfqq);
}
/*
* Called when the cfqq no longer has requests pending, remove it from
* the service tree.
*/
static inline void
cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
BUG_ON(!cfq_cfqq_on_rr(cfqq));
cfq_clear_cfqq_on_rr(cfqq);
list_del_init(&cfqq->cfq_list);
if (!RB_EMPTY_NODE(&cfqq->rb_node))
cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
......@@ -552,10 +605,14 @@ static struct request *
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
struct cfq_io_context *cic;
struct cfq_queue *cfqq;
cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
if (!cic)
return NULL;
cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
......@@ -579,6 +636,8 @@ static void cfq_activate_request(request_queue_t *q, struct request *rq)
*/
if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
cfqd->hw_tag = 1;
cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors;
}
static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
......@@ -605,8 +664,7 @@ static void cfq_remove_request(struct request *rq)
}
}
static int
cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
static int cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct request *__rq;
......@@ -648,23 +706,24 @@ static int cfq_allow_merge(request_queue_t *q, struct request *rq,
struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
const int rw = bio_data_dir(bio);
struct cfq_io_context *cic;
struct cfq_queue *cfqq;
pid_t key;
/*
* Disallow merge of a sync bio into an async request.
*/
if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq))
if (cfq_bio_sync(bio) && !rq_is_sync(rq))
return 0;
/*
* Lookup the cfqq that this bio will be queued with. Allow
* merge only if rq is queued there.
*/
key = cfq_queue_pid(current, rw, bio_sync(bio));
cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
cic = cfq_cic_rb_lookup(cfqd, current->io_context);
if (!cic)
return 0;
cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq == RQ_CFQQ(rq))
return 1;
......@@ -684,6 +743,7 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
cfq_mark_cfqq_slice_new(cfqq);
cfq_clear_cfqq_queue_new(cfqq);
}
cfqd->active_queue = cfqq;
......@@ -694,23 +754,21 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
*/
static void
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int preempted, int timed_out)
int timed_out)
{
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
cfq_clear_cfqq_queue_new(cfqq);
/*
* store what was left of this slice, if the queue idled out
* or was preempted
* 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_resort_rr_list(cfqq, preempted);
cfq_resort_rr_list(cfqd, cfqq);
if (cfqq == cfqd->active_queue)
cfqd->active_queue = NULL;
......@@ -719,163 +777,152 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
put_io_context(cfqd->active_cic->ioc);
cfqd->active_cic = NULL;
}
cfqd->dispatch_slice = 0;
}
static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted,
int timed_out)
static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
{
struct cfq_queue *cfqq = cfqd->active_queue;
if (cfqq)
__cfq_slice_expired(cfqd, cfqq, preempted, timed_out);
__cfq_slice_expired(cfqd, cfqq, timed_out);
}
/*
* 0
* 0,1
* 0,1,2
* 0,1,2,3
* 0,1,2,3,4
* 0,1,2,3,4,5
* 0,1,2,3,4,5,6
* 0,1,2,3,4,5,6,7
* Get next queue for service. Unless we have a queue preemption,
* we'll simply select the first cfqq in the service tree.
*/
static int cfq_get_next_prio_level(struct cfq_data *cfqd)
static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
{
int prio, wrap;
struct cfq_queue *cfqq;
struct rb_node *n;
prio = -1;
wrap = 0;
do {
int p;
if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
return NULL;
for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
if (!list_empty(&cfqd->rr_list[p])) {
prio = p;
break;
}
}
n = cfq_rb_first(&cfqd->service_tree);
cfqq = rb_entry(n, struct cfq_queue, rb_node);
if (prio != -1)
break;
cfqd->cur_prio = 0;
if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
cfqd->cur_end_prio = 0;
if (wrap)
break;
wrap = 1;
}
} while (1);
if (cfq_class_idle(cfqq)) {
unsigned long end;
if (unlikely(prio == -1))
return -1;
/*
* if we have idle queues and no rt or be queues had
* pending requests, either allow immediate service if
* the grace period has passed or arm the idle grace
* timer
*/
end = cfqd->last_end_request + CFQ_IDLE_GRACE;
if (time_before(jiffies, end)) {
mod_timer(&cfqd->idle_class_timer, end);
cfqq = NULL;
}
}
BUG_ON(prio >= CFQ_PRIO_LISTS);
return cfqq;
}
list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
/*
* 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;
cfqd->cur_prio = prio + 1;
if (cfqd->cur_prio > cfqd->cur_end_prio) {
cfqd->cur_end_prio = cfqd->cur_prio;
cfqd->cur_prio = 0;
}
if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
cfqd->cur_prio = 0;
cfqd->cur_end_prio = 0;
}
cfqq = cfq_get_next_queue(cfqd);
__cfq_set_active_queue(cfqd, cfqq);
return cfqq;
}
return prio;
static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
struct request *rq)
{
if (rq->sector >= cfqd->last_position)
return rq->sector - cfqd->last_position;
else
return cfqd->last_position - rq->sector;
}
static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
{
struct cfq_queue *cfqq = NULL;
struct cfq_io_context *cic = cfqd->active_cic;
if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
/*
* if current list is non-empty, grab first entry. if it is
* empty, get next prio level and grab first entry then if any
* are spliced
*/
cfqq = list_entry_cfqq(cfqd->cur_rr.next);
} else if (!list_empty(&cfqd->busy_rr)) {
/*
* If no new queues are available, check if the busy list has
* some before falling back to idle io.
*/
cfqq = list_entry_cfqq(cfqd->busy_rr.next);
} else if (!list_empty(&cfqd->idle_rr)) {
/*
* if we have idle queues and no rt or be queues had pending
* requests, either allow immediate service if the grace period
* has passed or arm the idle grace timer
*/
unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
if (!sample_valid(cic->seek_samples))
return 0;
if (time_after_eq(jiffies, end))
cfqq = list_entry_cfqq(cfqd->idle_rr.next);
else
mod_timer(&cfqd->idle_class_timer, end);
}
return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean;
}
__cfq_set_active_queue(cfqd, cfqq);
return cfqq;
static int cfq_close_cooperator(struct cfq_data *cfq_data,
struct cfq_queue *cfqq)
{
/*
* We should notice if some of the queues are cooperating, eg
* working closely on the same area of the disk. In that case,
* we can group them together and don't waste time idling.
*/
return 0;
}
#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024))
static int 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_io_context *cic;
unsigned long sl;
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)
return 0;
if (!cfq_cfqq_idle_window(cfqq))
return 0;
if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
return;
/*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
if (!cic || !cic->ioc->task)
return 0;
return;
/*
* See if this prio level has a good candidate
*/
if (cfq_close_cooperator(cfqd, cfqq) &&
(sample_valid(cic->ttime_samples) && cic->ttime_mean > 2))
return;
cfq_mark_cfqq_must_dispatch(cfqq);
cfq_mark_cfqq_wait_request(cfqq);
sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
/*
* 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;
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
sl = min(sl, msecs_to_jiffies(2));
sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
return 1;
}
/*
* Move request from internal lists to the request queue dispatch list.
*/
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_remove_request(rq);
cfqq->on_dispatch[rq_is_sync(rq)]++;
cfqq->dispatched++;
elv_dispatch_sort(q, rq);
rq = list_entry(q->queue_head.prev, struct request, queuelist);
cfqd->last_sector = rq->sector + rq->nr_sectors;
if (cfq_cfqq_sync(cfqq))
cfqd->sync_flight++;
}
/*
......@@ -895,13 +942,13 @@ static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
if (list_empty(&cfqq->fifo))
return NULL;
fifo = cfq_cfqq_class_sync(cfqq);
fifo = cfq_cfqq_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next);
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
return rq;
if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
return NULL;
return NULL;
return rq;
}
static inline int
......@@ -915,7 +962,8 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
}
/*
* get next queue for service
* 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)
{
......@@ -926,33 +974,41 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
goto new_queue;
/*
* slice has expired
* The active queue has run out of time, expire it and select new.
*/
if (!cfq_cfqq_must_dispatch(cfqq) && cfq_slice_used(cfqq))
if (cfq_slice_used(cfqq))
goto expire;
/*
* if queue has requests, dispatch one. if not, check if
* enough slice is left to wait for one
* The active queue has requests and isn't expired, allow it to
* dispatch.
*/
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
goto keep_queue;
else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
/*
* 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;
} else if (cfq_cfqq_class_sync(cfqq)) {
if (cfq_arm_slice_timer(cfqd))
return NULL;
}
expire:
cfq_slice_expired(cfqd, 0, 0);
cfq_slice_expired(cfqd, 0);
new_queue:
cfqq = cfq_set_active_queue(cfqd);
keep_queue:
return cfqq;
}
/*
* Dispatch some requests from cfqq, moving them to the request queue
* dispatch list.
*/
static int
__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int max_dispatch)
......@@ -975,7 +1031,6 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
*/
cfq_dispatch_insert(cfqd->queue, rq);
cfqd->dispatch_slice++;
dispatched++;
if (!cfqd->active_cic) {
......@@ -993,57 +1048,54 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* queue always expire after 1 dispatch round.
*/
if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
dispatched >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
cfq_class_idle(cfqq))) {
cfqq->slice_end = jiffies + 1;
cfq_slice_expired(cfqd, 0, 0);
cfq_slice_expired(cfqd, 0);
}
return dispatched;
}
static int
cfq_forced_dispatch_cfqqs(struct list_head *list)
static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
{
struct cfq_queue *cfqq, *next;
int dispatched;
int dispatched = 0;
dispatched = 0;
list_for_each_entry_safe(cfqq, next, list, cfq_list) {
while (cfqq->next_rq) {
cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
dispatched++;
}
BUG_ON(!list_empty(&cfqq->fifo));
while (cfqq->next_rq) {
cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
dispatched++;
}
BUG_ON(!list_empty(&cfqq->fifo));
return dispatched;
}
static int
cfq_forced_dispatch(struct cfq_data *cfqd)
/*
* Drain our current requests. Used for barriers and when switching
* io schedulers on-the-fly.
*/
static int cfq_forced_dispatch(struct cfq_data *cfqd)
{
int i, dispatched = 0;
int dispatched = 0;
struct rb_node *n;
for (i = 0; i < CFQ_PRIO_LISTS; i++)
dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]);
while ((n = cfq_rb_first(&cfqd->service_tree)) != NULL) {
struct cfq_queue *cfqq = rb_entry(n, struct cfq_queue, rb_node);
dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr);
dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
dispatched += __cfq_forced_dispatch_cfqq(cfqq);
}
cfq_slice_expired(cfqd, 0, 0);
cfq_slice_expired(cfqd, 0);
BUG_ON(cfqd->busy_queues);
return dispatched;
}
static int
cfq_dispatch_requests(request_queue_t *q, int force)
static int cfq_dispatch_requests(request_queue_t *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq, *prev_cfqq;
struct cfq_queue *cfqq;
int dispatched;
if (!cfqd->busy_queues)
......@@ -1053,36 +1105,28 @@ cfq_dispatch_requests(request_queue_t *q, int force)
return cfq_forced_dispatch(cfqd);
dispatched = 0;
prev_cfqq = NULL;
while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
int max_dispatch;
if (cfqd->busy_queues > 1) {
/*
* Don't repeat dispatch from the previous queue.
*/
if (prev_cfqq == cfqq)
break;
max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq))
max_dispatch = 1;
/*
* So we have dispatched before in this round, if the
* next queue has idling enabled (must be sync), don't
* allow it service until the previous have continued.
*/
if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
if (cfqq->dispatched >= max_dispatch) {
if (cfqd->busy_queues > 1)
break;
if (cfqq->dispatched >= 4 * max_dispatch)
break;
}
if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
break;
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
del_timer(&cfqd->idle_slice_timer);
max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq))
max_dispatch = 1;
dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
prev_cfqq = cfqq;
}
return dispatched;
......@@ -1108,48 +1152,21 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
BUG_ON(cfq_cfqq_on_rr(cfqq));
if (unlikely(cfqd->active_queue == cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0, 0);
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
/*
* it's on the empty list and still hashed
*/
list_del(&cfqq->cfq_list);
hlist_del(&cfqq->cfq_hash);
kmem_cache_free(cfq_pool, cfqq);
}
static struct cfq_queue *
__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
const int hashval)
{
struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
struct hlist_node *entry;
struct cfq_queue *__cfqq;
hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
if (__cfqq->key == key && (__p == prio || !prio))
return __cfqq;
}
return NULL;
}
static struct cfq_queue *
cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
{
return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
}
static void cfq_free_io_context(struct io_context *ioc)
{
struct cfq_io_context *__cic;
struct rb_node *n;
int freed = 0;
ioc->ioc_data = NULL;
while ((n = rb_first(&ioc->cic_root)) != NULL) {
__cic = rb_entry(n, struct cfq_io_context, rb_node);
rb_erase(&__cic->rb_node, &ioc->cic_root);
......@@ -1166,7 +1183,7 @@ 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, 0);
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
......@@ -1191,10 +1208,6 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
}
}
/*
* Called with interrupts disabled
*/
static void cfq_exit_single_io_context(struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
......@@ -1208,15 +1221,20 @@ static void cfq_exit_single_io_context(struct cfq_io_context *cic)
}
}
/*
* The process that ioc belongs to has exited, we need to clean up
* and put the internal structures we have that belongs to that process.
*/
static void cfq_exit_io_context(struct io_context *ioc)
{
struct cfq_io_context *__cic;
struct rb_node *n;
ioc->ioc_data = NULL;
/*
* put the reference this task is holding to the various queues
*/
n = rb_first(&ioc->cic_root);
while (n != NULL) {
__cic = rb_entry(n, struct cfq_io_context, rb_node);
......@@ -1284,8 +1302,6 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq)
*/
cfqq->org_ioprio = cfqq->ioprio;
cfqq->org_ioprio_class = cfqq->ioprio_class;
cfq_resort_rr_list(cfqq, 0);
cfq_clear_cfqq_prio_changed(cfqq);
}
......@@ -1303,7 +1319,7 @@ static inline void changed_ioprio(struct cfq_io_context *cic)
cfqq = cic->cfqq[ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
new_cfqq = cfq_get_queue(cfqd, ASYNC, cic->ioc->task,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[ASYNC] = new_cfqq;
......@@ -1335,16 +1351,16 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
}
static struct cfq_queue *
cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct task_struct *tsk,
gfp_t gfp_mask)
{
const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
struct cfq_queue *cfqq, *new_cfqq = NULL;
unsigned short ioprio;
struct cfq_io_context *cic;
retry:
ioprio = tsk->ioprio;
cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
/* cic always exists here */
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq) {
if (new_cfqq) {
......@@ -1369,20 +1385,20 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
memset(cfqq, 0, sizeof(*cfqq));
INIT_HLIST_NODE(&cfqq->cfq_hash);
INIT_LIST_HEAD(&cfqq->cfq_list);
RB_CLEAR_NODE(&cfqq->rb_node);
INIT_LIST_HEAD(&cfqq->fifo);
cfqq->key = key;
hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;
if (key != CFQ_KEY_ASYNC)
if (is_sync) {
cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_sync(cfqq);
}
cfq_mark_cfqq_prio_changed(cfqq);
cfq_mark_cfqq_queue_new(cfqq);
cfq_init_prio_data(cfqq);
}
......@@ -1395,10 +1411,17 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
return cfqq;
}
/*
* We drop cfq io contexts lazily, so we may find a dead one.
*/
static void
cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
{
WARN_ON(!list_empty(&cic->queue_list));
if (ioc->ioc_data == cic)
ioc->ioc_data = NULL;
rb_erase(&cic->rb_node, &ioc->cic_root);
kmem_cache_free(cfq_ioc_pool, cic);
elv_ioc_count_dec(ioc_count);
......@@ -1411,6 +1434,16 @@ cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
struct cfq_io_context *cic;
void *k, *key = cfqd;
if (unlikely(!ioc))
return NULL;
/*
* we maintain a last-hit cache, to avoid browsing over the tree
*/
cic = ioc->ioc_data;
if (cic && cic->key == cfqd)
return cic;
restart:
n = ioc->cic_root.rb_node;
while (n) {
......@@ -1426,8 +1459,10 @@ cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
n = n->rb_left;
else if (key > k)
n = n->rb_right;
else
else {
ioc->ioc_data = cic;
return cic;
}
}
return NULL;
......@@ -1524,7 +1559,8 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
}
static void
cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
struct request *rq)
{
sector_t sdist;
u64 total;
......@@ -1534,6 +1570,11 @@ cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
else
sdist = cic->last_request_pos - rq->sector;
if (!cic->seek_samples) {
cfqd->new_seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
cfqd->new_seek_mean = cfqd->new_seek_total / 256;
}
/*
* Don't allow the seek distance to get too large from the
* odd fragment, pagein, etc
......@@ -1558,7 +1599,12 @@ static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
int enable_idle = cfq_cfqq_idle_window(cfqq);
int enable_idle;
if (!cfq_cfqq_sync(cfqq))
return;
enable_idle = cfq_cfqq_idle_window(cfqq);
if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
(cfqd->hw_tag && CIC_SEEKY(cic)))
......@@ -1584,24 +1630,28 @@ static int
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
struct request *rq)
{
struct cfq_queue *cfqq = cfqd->active_queue;
struct cfq_queue *cfqq;
if (cfq_class_idle(new_cfqq))
cfqq = cfqd->active_queue;
if (!cfqq)
return 0;
if (!cfqq)
if (cfq_slice_used(cfqq))
return 1;
if (cfq_class_idle(new_cfqq))
return 0;
if (cfq_class_idle(cfqq))
return 1;
if (!cfq_cfqq_wait_request(new_cfqq))
return 0;
/*
* if the new request is sync, but the currently running queue is
* not, let the sync request have priority.
*/
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
return 1;
/*
* So both queues are sync. Let the new request get disk time if
* it's a metadata request and the current queue is doing regular IO.
......@@ -1609,6 +1659,16 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (rq_is_meta(rq) && !cfqq->meta_pending)
return 1;
if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
return 0;
/*
* if this request is as-good as one we would expect from the
* current cfqq, let it preempt
*/
if (cfq_rq_close(cfqd, rq))
return 1;
return 0;
}
......@@ -1618,14 +1678,15 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
*/
static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
cfq_slice_expired(cfqd, 1, 1);
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));
list_move(&cfqq->cfq_list, &cfqd->cur_rr);
cfq_service_tree_add(cfqd, cfqq, 1);
cfqq->slice_end = 0;
cfq_mark_cfqq_slice_new(cfqq);
......@@ -1644,28 +1705,12 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
if (rq_is_meta(rq))
cfqq->meta_pending++;
/*
* we never wait for an async request and we don't allow preemption
* of an async request. so just return early
*/
if (!rq_is_sync(rq)) {
/*
* sync process issued an async request, if it's waiting
* then expire it and kick rq handling.
*/
if (cic == cfqd->active_cic &&
del_timer(&cfqd->idle_slice_timer)) {
cfq_slice_expired(cfqd, 0, 0);
blk_start_queueing(cfqd->queue);
}
return;
}
cfq_update_io_thinktime(cfqd, cic);
cfq_update_io_seektime(cic, rq);
cfq_update_io_seektime(cfqd, cic, rq);
cfq_update_idle_window(cfqd, cfqq, cic);
cic->last_request_pos = rq->sector + rq->nr_sectors;
cfqq->last_request_pos = cic->last_request_pos;
if (cfqq == cfqd->active_queue) {
/*
......@@ -1714,16 +1759,16 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
now = jiffies;
WARN_ON(!cfqd->rq_in_driver);
WARN_ON(!cfqq->on_dispatch[sync]);
WARN_ON(!cfqq->dispatched);
cfqd->rq_in_driver--;
cfqq->on_dispatch[sync]--;
cfqq->service_last = now;
cfqq->dispatched--;
if (cfq_cfqq_sync(cfqq))
cfqd->sync_flight--;
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
cfq_resort_rr_list(cfqq, 0);
if (sync)
RQ_CIC(rq)->last_end_request = now;
......@@ -1737,12 +1782,13 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
cfq_clear_cfqq_slice_new(cfqq);
}
if (cfq_slice_used(cfqq))
cfq_slice_expired(cfqd, 0, 1);
else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
if (!cfq_arm_slice_timer(cfqd))
cfq_schedule_dispatch(cfqd);
}
cfq_slice_expired(cfqd, 1);
else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list))
cfq_arm_slice_timer(cfqd);
}
if (!cfqd->rq_in_driver)
cfq_schedule_dispatch(cfqd);
}
/*
......@@ -1751,9 +1797,6 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
*/
static void cfq_prio_boost(struct cfq_queue *cfqq)
{
const int ioprio_class = cfqq->ioprio_class;
const int ioprio = cfqq->ioprio;
if (has_fs_excl()) {
/*
* boost idle prio on transactions that would lock out other
......@@ -1772,12 +1815,6 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
if (cfqq->ioprio != cfqq->org_ioprio)
cfqq->ioprio = cfqq->org_ioprio;
}
/*
* refile between round-robin lists if we moved the priority class
*/
if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio))
cfq_resort_rr_list(cfqq, 0);
}
static inline int __cfq_may_queue(struct cfq_queue *cfqq)
......@@ -1795,10 +1832,8 @@ static int cfq_may_queue(request_queue_t *q, int rw)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
struct cfq_io_context *cic;
struct cfq_queue *cfqq;
unsigned int key;
key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC);
/*
* don't force setup of a queue from here, as a call to may_queue
......@@ -1806,7 +1841,11 @@ static int cfq_may_queue(request_queue_t *q, int rw)
* so just lookup a possibly existing queue, or return 'may queue'
* if that fails
*/
cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
if (!cic)
return ELV_MQUEUE_MAY;
cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC);
if (cfqq) {
cfq_init_prio_data(cfqq);
cfq_prio_boost(cfqq);
......@@ -1850,7 +1889,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
struct cfq_io_context *cic;
const int rw = rq_data_dir(rq);
const int is_sync = rq_is_sync(rq);
pid_t key = cfq_queue_pid(tsk, rw, is_sync);
struct cfq_queue *cfqq;
unsigned long flags;
......@@ -1863,14 +1901,15 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
if (!cic)
goto queue_fail;
if (!cic->cfqq[is_sync]) {
cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq) {
cfqq = cfq_get_queue(cfqd, is_sync, tsk, gfp_mask);
if (!cfqq)
goto queue_fail;
cic->cfqq[is_sync] = cfqq;
} else
cfqq = cic->cfqq[is_sync];
cic_set_cfqq(cic, cfqq, is_sync);
}
cfqq->allocated[rw]++;
cfq_clear_cfqq_must_alloc(cfqq);
......@@ -1940,7 +1979,7 @@ static void cfq_idle_slice_timer(unsigned long data)
}
}
expire:
cfq_slice_expired(cfqd, 0, timed_out);
cfq_slice_expired(cfqd, timed_out);
out_kick:
cfq_schedule_dispatch(cfqd);
out_cont:
......@@ -1986,7 +2025,7 @@ static void cfq_exit_queue(elevator_t *e)
spin_lock_irq(q->queue_lock);
if (cfqd->active_queue)
__cfq_slice_expired(cfqd, cfqd->active_queue, 0, 0);
__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,
......@@ -2000,14 +2039,12 @@ static void cfq_exit_queue(elevator_t *e)
cfq_shutdown_timer_wq(cfqd);
kfree(cfqd->cfq_hash);
kfree(cfqd);
}
static void *cfq_init_queue(request_queue_t *q)
{
struct cfq_data *cfqd;
int i;
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
if (!cfqd)
......@@ -2015,21 +2052,9 @@ static void *cfq_init_queue(request_queue_t *q)
memset(cfqd, 0, sizeof(*cfqd));
for (i = 0; i < CFQ_PRIO_LISTS; i++)
INIT_LIST_HEAD(&cfqd->rr_list[i]);
INIT_LIST_HEAD(&cfqd->busy_rr);
INIT_LIST_HEAD(&cfqd->cur_rr);
INIT_LIST_HEAD(&cfqd->idle_rr);
cfqd->service_tree = CFQ_RB_ROOT;
INIT_LIST_HEAD(&cfqd->cic_list);
cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
if (!cfqd->cfq_hash)
goto out_free;
for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
cfqd->queue = q;
init_timer(&cfqd->idle_slice_timer);
......@@ -2053,9 +2078,6 @@ static void *cfq_init_queue(request_queue_t *q)
cfqd->cfq_slice_idle = cfq_slice_idle;
return cfqd;
out_free:
kfree(cfqd);
return NULL;
}
static void cfq_slab_kill(void)
......@@ -2087,7 +2109,6 @@ static int __init cfq_slab_setup(void)
/*
* sysfs parts below -->
*/
static ssize_t
cfq_var_show(unsigned int var, char *page)
{
......
block/ll_rw_blk.c
浏览文件 @ 07e44708
......@@ -3741,6 +3741,7 @@ static struct io_context *current_io_context(gfp_t gfp_flags, int node)
ret->nr_batch_requests = 0; /* because this is 0 */
ret->aic = NULL;
ret->cic_root.rb_node = NULL;
ret->ioc_data = NULL;
/* make sure set_task_ioprio() sees the settings above */
smp_wmb();
tsk->io_context = ret;
......
include/linux/blkdev.h
浏览文件 @ 07e44708
......@@ -116,6 +116,7 @@ struct io_context {
struct as_io_context *aic;
struct rb_root cic_root;
void *ioc_data;
};
void put_io_context(struct io_context *ioc);
......
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