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Commit 5e705374 authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
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[PATCH] cfq-iosched: kill crq 

Get rid of the cfq_rq request type. With the added elevator_private2, we
have enough room in struct request to get rid of any crq allocation/free
for each request.
Signed-off-by: default avatarJens Axboe <axboe@suse.de>
parent ff7d145f
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Showing with 95 additions and 144 deletions
block/cfq-iosched.c
View file @ 5e705374
......@@ -43,9 +43,9 @@ static DEFINE_SPINLOCK(cfq_exit_lock);
#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
#define RQ_DATA(rq) (rq)->elevator_private
#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
#define RQ_CFQQ(rq) ((rq)->elevator_private2)
static kmem_cache_t *crq_pool;
static kmem_cache_t *cfq_pool;
static kmem_cache_t *cfq_ioc_pool;
......@@ -95,8 +95,6 @@ struct cfq_data {
*/
struct hlist_head *cfq_hash;
mempool_t *crq_pool;
int rq_in_driver;
int hw_tag;
......@@ -153,7 +151,7 @@ struct cfq_queue {
/* sorted list of pending requests */
struct rb_root sort_list;
/* if fifo isn't expired, next request to serve */
struct cfq_rq *next_crq;
struct request *next_rq;
/* requests queued in sort_list */
int queued[2];
/* currently allocated requests */
......@@ -177,13 +175,6 @@ struct cfq_queue {
unsigned int flags;
};
struct cfq_rq {
struct request *request;
struct cfq_queue *cfq_queue;
struct cfq_io_context *io_context;
};
enum cfqq_state_flags {
CFQ_CFQQ_FLAG_on_rr = 0,
CFQ_CFQQ_FLAG_wait_request,
......@@ -220,7 +211,7 @@ CFQ_CFQQ_FNS(prio_changed);
#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 cfq_rq *);
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);
/*
......@@ -249,12 +240,12 @@ static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
}
/*
* Lifted from AS - choose which of crq1 and crq2 that is best served now.
* Lifted from AS - choose which of rq1 and rq2 that is best served now.
* We choose the request that is closest to the head right now. Distance
* behind the head is penalized and only allowed to a certain extent.
*/
static struct cfq_rq *
cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
static struct request *
cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
{
sector_t last, s1, s2, d1 = 0, d2 = 0;
unsigned long back_max;
......@@ -262,18 +253,18 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
#define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
unsigned wrap = 0; /* bit mask: requests behind the disk head? */
if (crq1 == NULL || crq1 == crq2)
return crq2;
if (crq2 == NULL)
return crq1;
if (rq1 == NULL || rq1 == rq2)
return rq2;
if (rq2 == NULL)
return rq1;
if (rq_is_sync(crq1->request) && !rq_is_sync(crq2->request))
return crq1;
else if (rq_is_sync(crq2->request) && !rq_is_sync(crq1->request))
return crq2;
if (rq_is_sync(rq1) && !rq_is_sync(rq2))
return rq1;
else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
return rq2;
s1 = crq1->request->sector;
s2 = crq2->request->sector;
s1 = rq1->sector;
s2 = rq2->sector;
last = cfqd->last_sector;
......@@ -308,23 +299,23 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
* check two variables for all permutations: --> faster!
*/
switch (wrap) {
case 0: /* common case for CFQ: crq1 and crq2 not wrapped */
case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
if (d1 < d2)
return crq1;
return rq1;
else if (d2 < d1)
return crq2;
return rq2;
else {
if (s1 >= s2)
return crq1;
return rq1;
else
return crq2;
return rq2;
}
case CFQ_RQ2_WRAP:
return crq1;
return rq1;
case CFQ_RQ1_WRAP:
return crq2;
case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */
return rq2;
case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
default:
/*
* Since both rqs are wrapped,
......@@ -333,35 +324,34 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
* since back seek takes more time than forward.
*/
if (s1 <= s2)
return crq1;
return rq1;
else
return crq2;
return rq2;
}
}
/*
* would be nice to take fifo expire time into account as well
*/
static struct cfq_rq *
cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_rq *last_crq)
static struct request *
cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *last)
{
struct request *last = last_crq->request;
struct rb_node *rbnext = rb_next(&last->rb_node);
struct rb_node *rbprev = rb_prev(&last->rb_node);
struct cfq_rq *next = NULL, *prev = NULL;
struct request *next = NULL, *prev = NULL;
BUG_ON(RB_EMPTY_NODE(&last->rb_node));
if (rbprev)
prev = RQ_DATA(rb_entry_rq(rbprev));
prev = rb_entry_rq(rbprev);
if (rbnext)
next = RQ_DATA(rb_entry_rq(rbnext));
next = rb_entry_rq(rbnext);
else {
rbnext = rb_first(&cfqq->sort_list);
if (rbnext && rbnext != &last->rb_node)
next = RQ_DATA(rb_entry_rq(rbnext));
next = rb_entry_rq(rbnext);
}
return cfq_choose_req(cfqd, next, prev);
......@@ -450,26 +440,25 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
/*
* rb tree support functions
*/
static inline void cfq_del_crq_rb(struct cfq_rq *crq)
static inline void cfq_del_rq_rb(struct request *rq)
{
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = rq_is_sync(crq->request);
const int sync = rq_is_sync(rq);
BUG_ON(!cfqq->queued[sync]);
cfqq->queued[sync]--;
elv_rb_del(&cfqq->sort_list, crq->request);
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);
}
static void cfq_add_crq_rb(struct cfq_rq *crq)
static void cfq_add_rq_rb(struct request *rq)
{
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
struct request *rq = crq->request;
struct request *__alias;
cfqq->queued[rq_is_sync(rq)]++;
......@@ -479,17 +468,15 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
* if that happens, put the alias on the dispatch list
*/
while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
cfq_dispatch_insert(cfqd->queue, RQ_DATA(__alias));
cfq_dispatch_insert(cfqd->queue, __alias);
}
static inline void
cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
{
struct request *rq = crq->request;
elv_rb_del(&cfqq->sort_list, rq);
cfqq->queued[rq_is_sync(rq)]--;
cfq_add_crq_rb(crq);
cfq_add_rq_rb(rq);
}
static struct request *
......@@ -533,14 +520,13 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
static void cfq_remove_request(struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
if (cfqq->next_crq == crq)
cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
if (cfqq->next_rq == rq)
cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
list_del_init(&rq->queuelist);
cfq_del_crq_rb(crq);
cfq_del_rq_rb(rq);
}
static int
......@@ -561,12 +547,10 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
static void cfq_merged_request(request_queue_t *q, struct request *req,
int type)
{
struct cfq_rq *crq = RQ_DATA(req);
if (type == ELEVATOR_FRONT_MERGE) {
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(req);
cfq_reposition_crq_rb(cfqq, crq);
cfq_reposition_rq_rb(cfqq, req);
}
}
......@@ -789,11 +773,10 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
return 1;
}
static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = crq->cfq_queue;
struct request *rq = crq->request;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_remove_request(rq);
cfqq->on_dispatch[rq_is_sync(rq)]++;
......@@ -806,11 +789,10 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
/*
* return expired entry, or NULL to just start from scratch in rbtree
*/
static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
{
struct cfq_data *cfqd = cfqq->cfqd;
struct request *rq;
struct cfq_rq *crq;
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
......@@ -818,11 +800,10 @@ static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
if (!list_empty(&cfqq->fifo)) {
int fifo = cfq_cfqq_class_sync(cfqq);
crq = RQ_DATA(rq_entry_fifo(cfqq->fifo.next));
rq = crq->request;
rq = rq_entry_fifo(cfqq->fifo.next);
if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
cfq_mark_cfqq_fifo_expire(cfqq);
return crq;
return rq;
}
}
......@@ -909,25 +890,25 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
do {
struct cfq_rq *crq;
struct request *rq;
/*
* follow expired path, else get first next available
*/
if ((crq = cfq_check_fifo(cfqq)) == NULL)
crq = cfqq->next_crq;
if ((rq = cfq_check_fifo(cfqq)) == NULL)
rq = cfqq->next_rq;
/*
* finally, insert request into driver dispatch list
*/
cfq_dispatch_insert(cfqd->queue, crq);
cfq_dispatch_insert(cfqd->queue, rq);
cfqd->dispatch_slice++;
dispatched++;
if (!cfqd->active_cic) {
atomic_inc(&crq->io_context->ioc->refcount);
cfqd->active_cic = crq->io_context;
atomic_inc(&RQ_CIC(rq)->ioc->refcount);
cfqd->active_cic = RQ_CIC(rq);
}
if (RB_EMPTY_ROOT(&cfqq->sort_list))
......@@ -958,13 +939,12 @@ static int
cfq_forced_dispatch_cfqqs(struct list_head *list)
{
struct cfq_queue *cfqq, *next;
struct cfq_rq *crq;
int dispatched;
dispatched = 0;
list_for_each_entry_safe(cfqq, next, list, cfq_list) {
while ((crq = cfqq->next_crq)) {
cfq_dispatch_insert(cfqq->cfqd->queue, crq);
while (cfqq->next_rq) {
cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
dispatched++;
}
BUG_ON(!list_empty(&cfqq->fifo));
......@@ -1040,8 +1020,8 @@ cfq_dispatch_requests(request_queue_t *q, int force)
}
/*
* task holds one reference to the queue, dropped when task exits. each crq
* in-flight on this queue also holds a reference, dropped when crq is freed.
* 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.
*/
......@@ -1486,15 +1466,15 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
static void
cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
struct cfq_rq *crq)
struct request *rq)
{
sector_t sdist;
u64 total;
if (cic->last_request_pos < crq->request->sector)
sdist = crq->request->sector - cic->last_request_pos;
if (cic->last_request_pos < rq->sector)
sdist = rq->sector - cic->last_request_pos;
else
sdist = cic->last_request_pos - crq->request->sector;
sdist = cic->last_request_pos - rq->sector;
/*
* Don't allow the seek distance to get too large from the
......@@ -1545,7 +1525,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
*/
static int
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
struct cfq_rq *crq)
struct request *rq)
{
struct cfq_queue *cfqq = cfqd->active_queue;
......@@ -1564,7 +1544,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
*/
if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
return 0;
if (rq_is_sync(crq->request) && !cfq_cfqq_sync(cfqq))
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
return 1;
return 0;
......@@ -1603,26 +1583,26 @@ static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
}
/*
* Called when a new fs request (crq) is added (to cfqq). Check if there's
* Called when a new fs request (rq) is added (to cfqq). Check if there's
* something we should do about it
*/
static void
cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_rq *crq)
cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *rq)
{
struct cfq_io_context *cic = crq->io_context;
struct cfq_io_context *cic = RQ_CIC(rq);
/*
* check if this request is a better next-serve candidate)) {
*/
cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
BUG_ON(!cfqq->next_crq);
cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
BUG_ON(!cfqq->next_rq);
/*
* 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(crq->request)) {
if (!rq_is_sync(rq)) {
/*
* sync process issued an async request, if it's waiting
* then expire it and kick rq handling.
......@@ -1636,11 +1616,11 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
cfq_update_io_thinktime(cfqd, cic);
cfq_update_io_seektime(cfqd, cic, crq);
cfq_update_io_seektime(cfqd, cic, rq);
cfq_update_idle_window(cfqd, cfqq, cic);
cic->last_queue = jiffies;
cic->last_request_pos = crq->request->sector + crq->request->nr_sectors;
cic->last_request_pos = rq->sector + rq->nr_sectors;
if (cfqq == cfqd->active_queue) {
/*
......@@ -1653,7 +1633,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
del_timer(&cfqd->idle_slice_timer);
cfq_start_queueing(cfqd, cfqq);
}
} else if (cfq_should_preempt(cfqd, cfqq, crq)) {
} 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
......@@ -1668,25 +1648,23 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
static void cfq_insert_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_init_prio_data(cfqq);
cfq_add_crq_rb(crq);
cfq_add_rq_rb(rq);
if (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq);
list_add_tail(&rq->queuelist, &cfqq->fifo);
cfq_crq_enqueued(cfqd, cfqq, crq);
cfq_rq_enqueued(cfqd, cfqq, rq);
}
static void cfq_completed_request(request_queue_t *q, struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = crq->cfq_queue;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = rq_is_sync(rq);
unsigned long now;
......@@ -1709,7 +1687,7 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
}
if (sync)
crq->io_context->last_end_request = now;
RQ_CIC(rq)->last_end_request = now;
/*
* If this is the active queue, check if it needs to be expired,
......@@ -1817,20 +1795,18 @@ static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
*/
static void cfq_put_request(request_queue_t *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
struct cfq_queue *cfqq = RQ_CFQQ(rq);
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
if (cfqq) {
const int rw = rq_data_dir(rq);
BUG_ON(!cfqq->allocated[rw]);
cfqq->allocated[rw]--;
put_io_context(crq->io_context->ioc);
put_io_context(RQ_CIC(rq)->ioc);
mempool_free(crq, cfqd->crq_pool);
rq->elevator_private = NULL;
rq->elevator_private2 = NULL;
cfq_check_waiters(q, cfqq);
cfq_put_queue(cfqq);
......@@ -1850,7 +1826,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
const int rw = rq_data_dir(rq);
pid_t key = cfq_queue_pid(tsk, rw);
struct cfq_queue *cfqq;
struct cfq_rq *crq;
unsigned long flags;
int is_sync = key != CFQ_KEY_ASYNC;
......@@ -1876,23 +1851,13 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
cfq_clear_cfqq_must_alloc(cfqq);
cfqd->rq_starved = 0;
atomic_inc(&cfqq->ref);
spin_unlock_irqrestore(q->queue_lock, flags);
crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
if (crq) {
crq->request = rq;
crq->cfq_queue = cfqq;
crq->io_context = cic;
spin_unlock_irqrestore(q->queue_lock, flags);
rq->elevator_private = crq;
rq->elevator_private = cic;
rq->elevator_private2 = cfqq;
return 0;
}
spin_lock_irqsave(q->queue_lock, flags);
cfqq->allocated[rw]--;
if (!(cfqq->allocated[0] + cfqq->allocated[1]))
cfq_mark_cfqq_must_alloc(cfqq);
cfq_put_queue(cfqq);
queue_fail:
if (cic)
put_io_context(cic->ioc);
......@@ -2040,7 +2005,6 @@ static void cfq_exit_queue(elevator_t *e)
cfq_shutdown_timer_wq(cfqd);
mempool_destroy(cfqd->crq_pool);
kfree(cfqd->cfq_hash);
kfree(cfqd);
}
......@@ -2067,11 +2031,7 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL);
if (!cfqd->cfq_hash)
goto out_crqhash;
cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool);
if (!cfqd->crq_pool)
goto out_crqpool;
goto out_free;
for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
......@@ -2100,17 +2060,13 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
cfqd->cfq_slice_idle = cfq_slice_idle;
return cfqd;
out_crqpool:
kfree(cfqd->cfq_hash);
out_crqhash:
out_free:
kfree(cfqd);
return NULL;
}
static void cfq_slab_kill(void)
{
if (crq_pool)
kmem_cache_destroy(crq_pool);
if (cfq_pool)
kmem_cache_destroy(cfq_pool);
if (cfq_ioc_pool)
......@@ -2119,11 +2075,6 @@ static void cfq_slab_kill(void)
static int __init cfq_slab_setup(void)
{
crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0,
NULL, NULL);
if (!crq_pool)
goto fail;
cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
NULL, NULL);
if (!cfq_pool)
......
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