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block: prepare for multiple request_lists
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Request allocation is about to be made per-blkg meaning that there'll
be multiple request lists.

* Make queue full state per request_list.  blk_*queue_full() functions
  are renamed to blk_*rl_full() and takes @rl instead of @q.

* Rename blk_init_free_list() to blk_init_rl() and make it take @rl
  instead of @q.  Also add @gfp_mask parameter.

* Add blk_exit_rl() instead of destroying rl directly from
  blk_release_queue().

* Add request_list->q and make request alloc/free functions -
  blk_free_request(), [__]freed_request(), __get_request() - take @rl
  instead of @q.

This patch doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Tejun Heo authored and Jens Axboe committed Jun 25, 2012
1 parent 8a5ecdd commit 5b788ce
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Showing 4 changed files with 57 additions and 46 deletions.
56 changes: 31 additions & 25 deletions block/blk-core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -517,27 +517,33 @@ void blk_cleanup_queue(struct request_queue *q)
}
EXPORT_SYMBOL(blk_cleanup_queue);

static int blk_init_free_list(struct request_queue *q)
int blk_init_rl(struct request_list *rl, struct request_queue *q,
gfp_t gfp_mask)
{
struct request_list *rl = &q->rq;

if (unlikely(rl->rq_pool))
return 0;

rl->q = q;
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);

rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
mempool_free_slab, request_cachep,
GFP_KERNEL, q->node);
gfp_mask, q->node);
if (!rl->rq_pool)
return -ENOMEM;

return 0;
}

void blk_exit_rl(struct request_list *rl)
{
if (rl->rq_pool)
mempool_destroy(rl->rq_pool);
}

struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
{
return blk_alloc_queue_node(gfp_mask, -1);
Expand Down Expand Up @@ -679,7 +685,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
if (!q)
return NULL;

if (blk_init_free_list(q))
if (blk_init_rl(&q->rq, q, GFP_KERNEL))
return NULL;

q->request_fn = rfn;
Expand Down Expand Up @@ -721,15 +727,15 @@ bool blk_get_queue(struct request_queue *q)
}
EXPORT_SYMBOL(blk_get_queue);

static inline void blk_free_request(struct request_queue *q, struct request *rq)
static inline void blk_free_request(struct request_list *rl, struct request *rq)
{
if (rq->cmd_flags & REQ_ELVPRIV) {
elv_put_request(q, rq);
elv_put_request(rl->q, rq);
if (rq->elv.icq)
put_io_context(rq->elv.icq->ioc);
}

mempool_free(rq, q->rq.rq_pool);
mempool_free(rq, rl->rq_pool);
}

/*
Expand Down Expand Up @@ -766,9 +772,9 @@ static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
ioc->last_waited = jiffies;
}

static void __freed_request(struct request_queue *q, int sync)
static void __freed_request(struct request_list *rl, int sync)
{
struct request_list *rl = &q->rq;
struct request_queue *q = rl->q;

if (rl->count[sync] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, sync);
Expand All @@ -777,28 +783,28 @@ static void __freed_request(struct request_queue *q, int sync)
if (waitqueue_active(&rl->wait[sync]))
wake_up(&rl->wait[sync]);

blk_clear_queue_full(q, sync);
blk_clear_rl_full(rl, sync);
}
}

/*
* A request has just been released. Account for it, update the full and
* congestion status, wake up any waiters. Called under q->queue_lock.
*/
static void freed_request(struct request_queue *q, unsigned int flags)
static void freed_request(struct request_list *rl, unsigned int flags)
{
struct request_list *rl = &q->rq;
struct request_queue *q = rl->q;
int sync = rw_is_sync(flags);

q->nr_rqs[sync]--;
rl->count[sync]--;
if (flags & REQ_ELVPRIV)
q->nr_rqs_elvpriv--;

__freed_request(q, sync);
__freed_request(rl, sync);

if (unlikely(rl->starved[sync ^ 1]))
__freed_request(q, sync ^ 1);
__freed_request(rl, sync ^ 1);
}

/*
Expand Down Expand Up @@ -838,7 +844,7 @@ static struct io_context *rq_ioc(struct bio *bio)

/**
* __get_request - get a free request
* @q: request_queue to allocate request from
* @rl: request list to allocate from
* @rw_flags: RW and SYNC flags
* @bio: bio to allocate request for (can be %NULL)
* @gfp_mask: allocation mask
Expand All @@ -850,11 +856,11 @@ static struct io_context *rq_ioc(struct bio *bio)
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
*/
static struct request *__get_request(struct request_queue *q, int rw_flags,
static struct request *__get_request(struct request_list *rl, int rw_flags,
struct bio *bio, gfp_t gfp_mask)
{
struct request_queue *q = rl->q;
struct request *rq;
struct request_list *rl = &q->rq;
struct elevator_type *et = q->elevator->type;
struct io_context *ioc = rq_ioc(bio);
struct io_cq *icq = NULL;
Expand All @@ -876,9 +882,9 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
* This process will be allowed to complete a batch of
* requests, others will be blocked.
*/
if (!blk_queue_full(q, is_sync)) {
if (!blk_rl_full(rl, is_sync)) {
ioc_set_batching(q, ioc);
blk_set_queue_full(q, is_sync);
blk_set_rl_full(rl, is_sync);
} else {
if (may_queue != ELV_MQUEUE_MUST
&& !ioc_batching(q, ioc)) {
Expand Down Expand Up @@ -928,7 +934,7 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
spin_unlock_irq(q->queue_lock);

/* allocate and init request */
rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
rq = mempool_alloc(rl->rq_pool, gfp_mask);
if (!rq)
goto fail_alloc;

Expand Down Expand Up @@ -992,7 +998,7 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
* queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
freed_request(q, rw_flags);
freed_request(rl, rw_flags);

/*
* in the very unlikely event that allocation failed and no
Expand Down Expand Up @@ -1029,7 +1035,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
struct request_list *rl = &q->rq;
struct request *rq;
retry:
rq = __get_request(q, rw_flags, bio, gfp_mask);
rq = __get_request(&q->rq, rw_flags, bio, gfp_mask);
if (rq)
return rq;

Expand Down Expand Up @@ -1229,8 +1235,8 @@ void __blk_put_request(struct request_queue *q, struct request *req)
BUG_ON(!list_empty(&req->queuelist));
BUG_ON(!hlist_unhashed(&req->hash));

blk_free_request(q, req);
freed_request(q, flags);
blk_free_request(&q->rq, req);
freed_request(&q->rq, flags);
}
}
EXPORT_SYMBOL_GPL(__blk_put_request);
Expand Down
12 changes: 5 additions & 7 deletions block/blk-sysfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -66,16 +66,16 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
blk_clear_queue_congested(q, BLK_RW_ASYNC);

if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
blk_set_queue_full(q, BLK_RW_SYNC);
blk_set_rl_full(rl, BLK_RW_SYNC);
} else {
blk_clear_queue_full(q, BLK_RW_SYNC);
blk_clear_rl_full(rl, BLK_RW_SYNC);
wake_up(&rl->wait[BLK_RW_SYNC]);
}

if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
blk_set_queue_full(q, BLK_RW_ASYNC);
blk_set_rl_full(rl, BLK_RW_ASYNC);
} else {
blk_clear_queue_full(q, BLK_RW_ASYNC);
blk_clear_rl_full(rl, BLK_RW_ASYNC);
wake_up(&rl->wait[BLK_RW_ASYNC]);
}
spin_unlock_irq(q->queue_lock);
Expand Down Expand Up @@ -476,7 +476,6 @@ static void blk_release_queue(struct kobject *kobj)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
struct request_list *rl = &q->rq;

blk_sync_queue(q);

Expand All @@ -489,8 +488,7 @@ static void blk_release_queue(struct kobject *kobj)
elevator_exit(q->elevator);
}

if (rl->rq_pool)
mempool_destroy(rl->rq_pool);
blk_exit_rl(&q->rq);

if (q->queue_tags)
__blk_queue_free_tags(q);
Expand Down
3 changes: 3 additions & 0 deletions block/blk.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,9 @@ static inline void __blk_get_queue(struct request_queue *q)
kobject_get(&q->kobj);
}

int blk_init_rl(struct request_list *rl, struct request_queue *q,
gfp_t gfp_mask);
void blk_exit_rl(struct request_list *rl);
void init_request_from_bio(struct request *req, struct bio *bio);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
Expand Down
32 changes: 18 additions & 14 deletions include/linux/blkdev.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,12 @@ struct blkcg_gq;
struct request;
typedef void (rq_end_io_fn)(struct request *, int);

#define BLK_RL_SYNCFULL (1U << 0)
#define BLK_RL_ASYNCFULL (1U << 1)

struct request_list {
struct request_queue *q; /* the queue this rl belongs to */

/*
* count[], starved[], and wait[] are indexed by
* BLK_RW_SYNC/BLK_RW_ASYNC
Expand All @@ -55,6 +60,7 @@ struct request_list {
int starved[2];
mempool_t *rq_pool;
wait_queue_head_t wait[2];
unsigned int flags;
};

/*
Expand Down Expand Up @@ -562,27 +568,25 @@ static inline bool rq_is_sync(struct request *rq)
return rw_is_sync(rq->cmd_flags);
}

static inline int blk_queue_full(struct request_queue *q, int sync)
static inline bool blk_rl_full(struct request_list *rl, bool sync)
{
if (sync)
return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;

return rl->flags & flag;
}

static inline void blk_set_queue_full(struct request_queue *q, int sync)
static inline void blk_set_rl_full(struct request_list *rl, bool sync)
{
if (sync)
queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
else
queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;

rl->flags |= flag;
}

static inline void blk_clear_queue_full(struct request_queue *q, int sync)
static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
{
if (sync)
queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
else
queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;

rl->flags &= ~flag;
}


Expand Down

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