static DEFINE_MUTEX(all_q_mutex);
static LIST_HEAD(all_q_list);
+static void blk_mq_poll_stats_start(struct request_queue *q);
+static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
+
+static int blk_mq_poll_stats_bkt(const struct request *rq)
+{
+ int ddir, bytes, bucket;
+
+ ddir = rq_data_dir(rq);
+ bytes = blk_rq_bytes(rq);
+
+ bucket = ddir + 2*(ilog2(bytes) - 9);
+
+ if (bucket < 0)
+ return -1;
+ else if (bucket >= BLK_MQ_POLL_STATS_BKTS)
+ return ddir + BLK_MQ_POLL_STATS_BKTS - 2;
+
+ return bucket;
+}
+
/*
* Check if any of the ctx's have pending work in this hardware queue
*/
sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
}
-void blk_mq_freeze_queue_start(struct request_queue *q)
+void blk_freeze_queue_start(struct request_queue *q)
{
int freeze_depth;
blk_mq_run_hw_queues(q, false);
}
}
-EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start);
+EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
void blk_mq_freeze_queue_wait(struct request_queue *q)
{
* no blk_unfreeze_queue(), and blk_freeze_queue() is not
* exported to drivers as the only user for unfreeze is blk_mq.
*/
- blk_mq_freeze_queue_start(q);
+ blk_freeze_queue_start(q);
blk_mq_freeze_queue_wait(q);
}
#endif
rq->special = NULL;
/* tag was already set */
- rq->errors = 0;
rq->extra_len = 0;
INIT_LIST_HEAD(&rq->timeout_list);
if (rq->tag != -1)
blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
if (sched_tag != -1)
- blk_mq_sched_completed_request(hctx, rq);
+ blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag);
blk_mq_sched_restart(hctx);
blk_queue_exit(q);
}
{
blk_mq_finish_hctx_request(blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), rq);
}
+EXPORT_SYMBOL_GPL(blk_mq_finish_request);
void blk_mq_free_request(struct request *rq)
{
rq->q->softirq_done_fn(rq);
}
-static void blk_mq_ipi_complete_request(struct request *rq)
+static void __blk_mq_complete_request(struct request *rq)
{
struct blk_mq_ctx *ctx = rq->mq_ctx;
bool shared = false;
int cpu;
+ if (rq->internal_tag != -1)
+ blk_mq_sched_completed_request(rq);
+ if (rq->rq_flags & RQF_STATS) {
+ blk_mq_poll_stats_start(rq->q);
+ blk_stat_add(rq);
+ }
+
if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) {
rq->q->softirq_done_fn(rq);
return;
put_cpu();
}
-static void blk_mq_stat_add(struct request *rq)
-{
- if (rq->rq_flags & RQF_STATS) {
- /*
- * We could rq->mq_ctx here, but there's less of a risk
- * of races if we have the completion event add the stats
- * to the local software queue.
- */
- struct blk_mq_ctx *ctx;
-
- ctx = __blk_mq_get_ctx(rq->q, raw_smp_processor_id());
- blk_stat_add(&ctx->stat[rq_data_dir(rq)], rq);
- }
-}
-
-static void __blk_mq_complete_request(struct request *rq)
-{
- struct request_queue *q = rq->q;
-
- blk_mq_stat_add(rq);
-
- if (!q->softirq_done_fn)
- blk_mq_end_request(rq, rq->errors);
- else
- blk_mq_ipi_complete_request(rq);
-}
-
/**
* blk_mq_complete_request - end I/O on a request
* @rq: the request being processed
* Ends all I/O on a request. It does not handle partial completions.
* The actual completion happens out-of-order, through a IPI handler.
**/
-void blk_mq_complete_request(struct request *rq, int error)
+void blk_mq_complete_request(struct request *rq)
{
struct request_queue *q = rq->q;
if (unlikely(blk_should_fake_timeout(q)))
return;
- if (!blk_mark_rq_complete(rq)) {
- rq->errors = error;
+ if (!blk_mark_rq_complete(rq))
__blk_mq_complete_request(rq);
- }
}
EXPORT_SYMBOL(blk_mq_complete_request);
trace_block_rq_issue(q, rq);
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
- blk_stat_set_issue_time(&rq->issue_stat);
+ blk_stat_set_issue(&rq->issue_stat, blk_rq_sectors(rq));
rq->rq_flags |= RQF_STATS;
wbt_issue(q->rq_wb, &rq->issue_stat);
}
}
EXPORT_SYMBOL(blk_mq_start_request);
+/*
+ * When we reach here because queue is busy, REQ_ATOM_COMPLETE
+ * flag isn't set yet, so there may be race with timeout handler,
+ * but given rq->deadline is just set in .queue_rq() under
+ * this situation, the race won't be possible in reality because
+ * rq->timeout should be set as big enough to cover the window
+ * between blk_mq_start_request() called from .queue_rq() and
+ * clearing REQ_ATOM_STARTED here.
+ */
static void __blk_mq_requeue_request(struct request *rq)
{
struct request_queue *q = rq->q;
rq = list_first_entry(&rq_list, struct request, queuelist);
list_del_init(&rq->queuelist);
- rq->errors = -EIO;
- blk_mq_end_request(rq, rq->errors);
+ blk_mq_end_request(rq, -EIO);
}
}
EXPORT_SYMBOL(blk_mq_abort_requeue_list);
* just be ignored. This can happen due to the bitflag ordering.
* Timeout first checks if STARTED is set, and if it is, assumes
* the request is active. But if we race with completion, then
- * we both flags will get cleared. So check here again, and ignore
+ * both flags will get cleared. So check here again, and ignore
* a timeout event with a request that isn't active.
*/
if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags))
if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
return;
+ /*
+ * The rq being checked may have been freed and reallocated
+ * out already here, we avoid this race by checking rq->deadline
+ * and REQ_ATOM_COMPLETE flag together:
+ *
+ * - if rq->deadline is observed as new value because of
+ * reusing, the rq won't be timed out because of timing.
+ * - if rq->deadline is observed as previous value,
+ * REQ_ATOM_COMPLETE flag won't be cleared in reuse path
+ * because we put a barrier between setting rq->deadline
+ * and clearing the flag in blk_mq_start_request(), so
+ * this rq won't be timed out too.
+ */
if (time_after_eq(jiffies, rq->deadline)) {
if (!blk_mark_rq_complete(rq))
blk_mq_rq_timed_out(rq, reserved);
* percpu_ref_tryget directly, because we need to be able to
* obtain a reference even in the short window between the queue
* starting to freeze, by dropping the first reference in
- * blk_mq_freeze_queue_start, and the moment the last request is
+ * blk_freeze_queue_start, and the moment the last request is
* consumed, marked by the instant q_usage_counter reaches
* zero.
*/
.flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
};
+ might_sleep_if(wait);
+
if (rq->tag != -1)
goto done;
{
struct blk_mq_hw_ctx *hctx;
struct request *rq;
- LIST_HEAD(driver_list);
- struct list_head *dptr;
int errors, queued, ret = BLK_MQ_RQ_QUEUE_OK;
if (list_empty(list))
return false;
- /*
- * Start off with dptr being NULL, so we start the first request
- * immediately, even if we have more pending.
- */
- dptr = NULL;
-
/*
* Now process all the entries, sending them to the driver.
*/
* The initial allocation attempt failed, so we need to
* rerun the hardware queue when a tag is freed.
*/
- if (blk_mq_dispatch_wait_add(hctx)) {
- /*
- * It's possible that a tag was freed in the
- * window between the allocation failure and
- * adding the hardware queue to the wait queue.
- */
- if (!blk_mq_get_driver_tag(rq, &hctx, false))
- break;
- } else {
+ if (!blk_mq_dispatch_wait_add(hctx))
+ break;
+
+ /*
+ * It's possible that a tag was freed in the window
+ * between the allocation failure and adding the
+ * hardware queue to the wait queue.
+ */
+ if (!blk_mq_get_driver_tag(rq, &hctx, false))
break;
- }
}
list_del_init(&rq->queuelist);
bd.rq = rq;
- bd.list = dptr;
/*
* Flag last if we have no more requests, or if we have more
pr_err("blk-mq: bad return on queue: %d\n", ret);
case BLK_MQ_RQ_QUEUE_ERROR:
errors++;
- rq->errors = -EIO;
- blk_mq_end_request(rq, rq->errors);
+ blk_mq_end_request(rq, -EIO);
break;
}
if (ret == BLK_MQ_RQ_QUEUE_BUSY)
break;
-
- /*
- * We've done the first request. If we have more than 1
- * left in the list, set dptr to defer issue.
- */
- if (!dptr && list->next != list->prev)
- dptr = &driver_list;
} while (!list_empty(list));
hctx->dispatched[queued_to_index(queued)]++;
*/
if (!list_empty(list)) {
/*
- * If we got a driver tag for the next request already,
- * free it again.
+ * If an I/O scheduler has been configured and we got a driver
+ * tag for the next request already, free it again.
*/
rq = list_first_entry(list, struct request, queuelist);
blk_mq_put_driver_tag(rq);
spin_unlock(&hctx->lock);
/*
- * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
- * it's possible the queue is stopped and restarted again
- * before this. Queue restart will dispatch requests. And since
- * requests in rq_list aren't added into hctx->dispatch yet,
- * the requests in rq_list might get lost.
+ * If SCHED_RESTART was set by the caller of this function and
+ * it is no longer set that means that it was cleared by another
+ * thread and hence that a queue rerun is needed.
*
- * blk_mq_run_hw_queue() already checks the STOPPED bit
+ * If TAG_WAITING is set that means that an I/O scheduler has
+ * been configured and another thread is waiting for a driver
+ * tag. To guarantee fairness, do not rerun this hardware queue
+ * but let the other thread grab the driver tag.
*
- * If RESTART or TAG_WAITING is set, then let completion restart
- * the queue instead of potentially looping here.
+ * If no I/O scheduler has been configured it is possible that
+ * the hardware queue got stopped and restarted before requests
+ * were pushed back onto the dispatch list. Rerun the queue to
+ * avoid starvation. Notes:
+ * - blk_mq_run_hw_queue() checks whether or not a queue has
+ * been stopped before rerunning a queue.
+ * - Some but not all block drivers stop a queue before
+ * returning BLK_MQ_RQ_QUEUE_BUSY. Two exceptions are scsi-mq
+ * and dm-rq.
*/
if (!blk_mq_sched_needs_restart(hctx) &&
!test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state))
blk_mq_sched_dispatch_requests(hctx);
rcu_read_unlock();
} else {
+ might_sleep();
+
srcu_idx = srcu_read_lock(&hctx->queue_rq_srcu);
blk_mq_sched_dispatch_requests(hctx);
srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx);
put_cpu();
}
- if (msecs == 0)
- kblockd_schedule_work_on(blk_mq_hctx_next_cpu(hctx),
- &hctx->run_work);
- else
- kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
- &hctx->delayed_run_work,
- msecs_to_jiffies(msecs));
+ kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
+ &hctx->run_work,
+ msecs_to_jiffies(msecs));
}
void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
{
__blk_mq_delay_run_hw_queue(hctx, async, 0);
}
+EXPORT_SYMBOL(blk_mq_run_hw_queue);
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
{
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
- cancel_work(&hctx->run_work);
- cancel_delayed_work(&hctx->delay_work);
+ cancel_delayed_work_sync(&hctx->run_work);
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
{
struct blk_mq_hw_ctx *hctx;
- hctx = container_of(work, struct blk_mq_hw_ctx, run_work);
-
- __blk_mq_run_hw_queue(hctx);
-}
+ hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
-static void blk_mq_delayed_run_work_fn(struct work_struct *work)
-{
- struct blk_mq_hw_ctx *hctx;
+ /*
+ * If we are stopped, don't run the queue. The exception is if
+ * BLK_MQ_S_START_ON_RUN is set. For that case, we auto-clear
+ * the STOPPED bit and run it.
+ */
+ if (test_bit(BLK_MQ_S_STOPPED, &hctx->state)) {
+ if (!test_bit(BLK_MQ_S_START_ON_RUN, &hctx->state))
+ return;
- hctx = container_of(work, struct blk_mq_hw_ctx, delayed_run_work.work);
+ clear_bit(BLK_MQ_S_START_ON_RUN, &hctx->state);
+ clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
+ }
__blk_mq_run_hw_queue(hctx);
}
-static void blk_mq_delay_work_fn(struct work_struct *work)
-{
- struct blk_mq_hw_ctx *hctx;
-
- hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work);
-
- if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state))
- __blk_mq_run_hw_queue(hctx);
-}
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
{
if (unlikely(!blk_mq_hw_queue_mapped(hctx)))
return;
+ /*
+ * Stop the hw queue, then modify currently delayed work.
+ * This should prevent us from running the queue prematurely.
+ * Mark the queue as auto-clearing STOPPED when it runs.
+ */
blk_mq_stop_hw_queue(hctx);
- kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
- &hctx->delay_work, msecs_to_jiffies(msecs));
+ set_bit(BLK_MQ_S_START_ON_RUN, &hctx->state);
+ kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
+ &hctx->run_work,
+ msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL(blk_mq_delay_queue);
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
{
- init_request_from_bio(rq, bio);
+ blk_init_request_from_bio(rq, bio);
blk_account_io_start(rq, true);
}
return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
}
-static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
+static void __blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
bool may_sleep)
{
struct request_queue *q = rq->q;
struct blk_mq_queue_data bd = {
.rq = rq,
- .list = NULL,
- .last = 1
+ .last = true,
};
struct blk_mq_hw_ctx *hctx;
blk_qc_t new_cookie;
return;
}
- __blk_mq_requeue_request(rq);
-
if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
*cookie = BLK_QC_T_NONE;
- rq->errors = -EIO;
- blk_mq_end_request(rq, rq->errors);
+ blk_mq_end_request(rq, -EIO);
return;
}
+ __blk_mq_requeue_request(rq);
insert:
blk_mq_sched_insert_request(rq, false, true, false, may_sleep);
}
-/*
- * Multiple hardware queue variant. This will not use per-process plugs,
- * but will attempt to bypass the hctx queueing if we can go straight to
- * hardware for SYNC IO.
- */
+static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+ struct request *rq, blk_qc_t *cookie)
+{
+ if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
+ rcu_read_lock();
+ __blk_mq_try_issue_directly(rq, cookie, false);
+ rcu_read_unlock();
+ } else {
+ unsigned int srcu_idx;
+
+ might_sleep();
+
+ srcu_idx = srcu_read_lock(&hctx->queue_rq_srcu);
+ __blk_mq_try_issue_directly(rq, cookie, true);
+ srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx);
+ }
+}
+
static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
{
const int is_sync = op_is_sync(bio->bi_opf);
const int is_flush_fua = op_is_flush(bio->bi_opf);
struct blk_mq_alloc_data data = { .flags = 0 };
struct request *rq;
- unsigned int request_count = 0, srcu_idx;
+ unsigned int request_count = 0;
struct blk_plug *plug;
struct request *same_queue_rq = NULL;
blk_qc_t cookie;
cookie = request_to_qc_t(data.hctx, rq);
- if (unlikely(is_flush_fua)) {
- if (q->elevator)
- goto elv_insert;
- blk_mq_bio_to_request(rq, bio);
- blk_insert_flush(rq);
- goto run_queue;
- }
-
plug = current->plug;
- /*
- * If the driver supports defer issued based on 'last', then
- * queue it up like normal since we can potentially save some
- * CPU this way.
- */
- if (((plug && !blk_queue_nomerges(q)) || is_sync) &&
- !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) {
- struct request *old_rq = NULL;
-
- blk_mq_bio_to_request(rq, bio);
-
- /*
- * We do limited plugging. If the bio can be merged, do that.
- * Otherwise the existing request in the plug list will be
- * issued. So the plug list will have one request at most
- */
- if (plug) {
- /*
- * The plug list might get flushed before this. If that
- * happens, same_queue_rq is invalid and plug list is
- * empty
- */
- if (same_queue_rq && !list_empty(&plug->mq_list)) {
- old_rq = same_queue_rq;
- list_del_init(&old_rq->queuelist);
- }
- list_add_tail(&rq->queuelist, &plug->mq_list);
- } else /* is_sync */
- old_rq = rq;
+ if (unlikely(is_flush_fua)) {
blk_mq_put_ctx(data.ctx);
- if (!old_rq)
- goto done;
-
- if (!(data.hctx->flags & BLK_MQ_F_BLOCKING)) {
- rcu_read_lock();
- blk_mq_try_issue_directly(old_rq, &cookie, false);
- rcu_read_unlock();
+ blk_mq_bio_to_request(rq, bio);
+ if (q->elevator) {
+ blk_mq_sched_insert_request(rq, false, true, true,
+ true);
} else {
- srcu_idx = srcu_read_lock(&data.hctx->queue_rq_srcu);
- blk_mq_try_issue_directly(old_rq, &cookie, true);
- srcu_read_unlock(&data.hctx->queue_rq_srcu, srcu_idx);
+ blk_insert_flush(rq);
+ blk_mq_run_hw_queue(data.hctx, true);
}
- goto done;
- }
-
- if (q->elevator) {
-elv_insert:
- blk_mq_put_ctx(data.ctx);
- blk_mq_bio_to_request(rq, bio);
- blk_mq_sched_insert_request(rq, false, true,
- !is_sync || is_flush_fua, true);
- goto done;
- }
- if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
- /*
- * For a SYNC request, send it to the hardware immediately. For
- * an ASYNC request, just ensure that we run it later on. The
- * latter allows for merging opportunities and more efficient
- * dispatching.
- */
-run_queue:
- blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
- }
- blk_mq_put_ctx(data.ctx);
-done:
- return cookie;
-}
-
-/*
- * Single hardware queue variant. This will attempt to use any per-process
- * plug for merging and IO deferral.
- */
-static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
-{
- const int is_sync = op_is_sync(bio->bi_opf);
- const int is_flush_fua = op_is_flush(bio->bi_opf);
- struct blk_plug *plug;
- unsigned int request_count = 0;
- struct blk_mq_alloc_data data = { .flags = 0 };
- struct request *rq;
- blk_qc_t cookie;
- unsigned int wb_acct;
-
- blk_queue_bounce(q, &bio);
-
- if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
- bio_io_error(bio);
- return BLK_QC_T_NONE;
- }
-
- blk_queue_split(q, &bio, q->bio_split);
-
- if (!is_flush_fua && !blk_queue_nomerges(q)) {
- if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
- return BLK_QC_T_NONE;
- } else
- request_count = blk_plug_queued_count(q);
-
- if (blk_mq_sched_bio_merge(q, bio))
- return BLK_QC_T_NONE;
-
- wb_acct = wbt_wait(q->rq_wb, bio, NULL);
-
- trace_block_getrq(q, bio, bio->bi_opf);
-
- rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data);
- if (unlikely(!rq)) {
- __wbt_done(q->rq_wb, wb_acct);
- return BLK_QC_T_NONE;
- }
-
- wbt_track(&rq->issue_stat, wb_acct);
-
- cookie = request_to_qc_t(data.hctx, rq);
-
- if (unlikely(is_flush_fua)) {
- if (q->elevator)
- goto elv_insert;
- blk_mq_bio_to_request(rq, bio);
- blk_insert_flush(rq);
- goto run_queue;
- }
-
- /*
- * A task plug currently exists. Since this is completely lockless,
- * utilize that to temporarily store requests until the task is
- * either done or scheduled away.
- */
- plug = current->plug;
- if (plug) {
+ } else if (plug && q->nr_hw_queues == 1) {
struct request *last = NULL;
+ blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
/*
*/
if (list_empty(&plug->mq_list))
request_count = 0;
+ else if (blk_queue_nomerges(q))
+ request_count = blk_plug_queued_count(q);
+
if (!request_count)
trace_block_plug(q);
else
last = list_entry_rq(plug->mq_list.prev);
- blk_mq_put_ctx(data.ctx);
-
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
blk_flush_plug_list(plug, false);
}
list_add_tail(&rq->queuelist, &plug->mq_list);
- return cookie;
- }
-
- if (q->elevator) {
-elv_insert:
- blk_mq_put_ctx(data.ctx);
+ } else if (plug && !blk_queue_nomerges(q)) {
blk_mq_bio_to_request(rq, bio);
- blk_mq_sched_insert_request(rq, false, true,
- !is_sync || is_flush_fua, true);
- goto done;
- }
- if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
+
/*
- * For a SYNC request, send it to the hardware immediately. For
- * an ASYNC request, just ensure that we run it later on. The
- * latter allows for merging opportunities and more efficient
- * dispatching.
+ * We do limited plugging. If the bio can be merged, do that.
+ * Otherwise the existing request in the plug list will be
+ * issued. So the plug list will have one request at most
+ * The plug list might get flushed before this. If that happens,
+ * the plug list is empty, and same_queue_rq is invalid.
*/
-run_queue:
- blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
- }
+ if (list_empty(&plug->mq_list))
+ same_queue_rq = NULL;
+ if (same_queue_rq)
+ list_del_init(&same_queue_rq->queuelist);
+ list_add_tail(&rq->queuelist, &plug->mq_list);
+
+ blk_mq_put_ctx(data.ctx);
+
+ if (same_queue_rq)
+ blk_mq_try_issue_directly(data.hctx, same_queue_rq,
+ &cookie);
+ } else if (q->nr_hw_queues > 1 && is_sync) {
+ blk_mq_put_ctx(data.ctx);
+ blk_mq_bio_to_request(rq, bio);
+ blk_mq_try_issue_directly(data.hctx, rq, &cookie);
+ } else if (q->elevator) {
+ blk_mq_put_ctx(data.ctx);
+ blk_mq_bio_to_request(rq, bio);
+ blk_mq_sched_insert_request(rq, false, true, true, true);
+ } else if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
+ blk_mq_put_ctx(data.ctx);
+ blk_mq_run_hw_queue(data.hctx, true);
+ } else
+ blk_mq_put_ctx(data.ctx);
- blk_mq_put_ctx(data.ctx);
-done:
return cookie;
}
if (node == NUMA_NO_NODE)
node = hctx->numa_node = set->numa_node;
- INIT_WORK(&hctx->run_work, blk_mq_run_work_fn);
- INIT_DELAYED_WORK(&hctx->delayed_run_work, blk_mq_delayed_run_work_fn);
- INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
+ INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
spin_lock_init(&hctx->lock);
INIT_LIST_HEAD(&hctx->dispatch);
hctx->queue = q;
spin_lock_init(&__ctx->lock);
INIT_LIST_HEAD(&__ctx->rq_list);
__ctx->queue = q;
- blk_stat_init(&__ctx->stat[BLK_STAT_READ]);
- blk_stat_init(&__ctx->stat[BLK_STAT_WRITE]);
/* If the cpu isn't online, the cpu is mapped to first hctx */
if (!cpu_online(i))
{
struct request_queue *q;
+ lockdep_assert_held(&set->tag_list_lock);
+
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_freeze_queue(q);
queue_set_hctx_shared(q, shared);
struct blk_mq_tag_set *set = q->tag_set;
mutex_lock(&set->tag_list_lock);
- list_del_init(&q->tag_set_list);
+ list_del_rcu(&q->tag_set_list);
+ INIT_LIST_HEAD(&q->tag_set_list);
if (list_is_singular(&set->tag_list)) {
/* just transitioned to unshared */
set->flags &= ~BLK_MQ_F_TAG_SHARED;
blk_mq_update_tag_set_depth(set, false);
}
mutex_unlock(&set->tag_list_lock);
+
+ synchronize_rcu();
}
static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
}
if (set->flags & BLK_MQ_F_TAG_SHARED)
queue_set_hctx_shared(q, true);
- list_add_tail(&q->tag_set_list, &set->tag_list);
+ list_add_tail_rcu(&q->tag_set_list, &set->tag_list);
mutex_unlock(&set->tag_list_lock);
}
/* mark the queue as mq asap */
q->mq_ops = set->ops;
+ q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn,
+ blk_mq_poll_stats_bkt,
+ BLK_MQ_POLL_STATS_BKTS, q);
+ if (!q->poll_cb)
+ goto err_exit;
+
q->queue_ctx = alloc_percpu(struct blk_mq_ctx);
if (!q->queue_ctx)
goto err_exit;
INIT_LIST_HEAD(&q->requeue_list);
spin_lock_init(&q->requeue_lock);
- if (q->nr_hw_queues > 1)
- blk_queue_make_request(q, blk_mq_make_request);
- else
- blk_queue_make_request(q, blk_sq_make_request);
+ blk_queue_make_request(q, blk_mq_make_request);
/*
* Do this after blk_queue_make_request() overrides it...
list_del_init(&q->all_q_node);
mutex_unlock(&all_q_mutex);
- wbt_exit(q);
-
blk_mq_del_queue_tag_set(q);
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
* take place in parallel.
*/
list_for_each_entry(q, &all_q_list, all_q_node)
- blk_mq_freeze_queue_start(q);
+ blk_freeze_queue_start(q);
list_for_each_entry(q, &all_q_list, all_q_node)
blk_mq_freeze_queue_wait(q);
{
struct request_queue *q;
+ lockdep_assert_held(&set->tag_list_lock);
+
if (nr_hw_queues > nr_cpu_ids)
nr_hw_queues = nr_cpu_ids;
if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
blk_mq_update_queue_map(set);
list_for_each_entry(q, &set->tag_list, tag_set_list) {
blk_mq_realloc_hw_ctxs(set, q);
-
- /*
- * Manually set the make_request_fn as blk_queue_make_request
- * resets a lot of the queue settings.
- */
- if (q->nr_hw_queues > 1)
- q->make_request_fn = blk_mq_make_request;
- else
- q->make_request_fn = blk_sq_make_request;
-
blk_mq_queue_reinit(q, cpu_online_mask);
}
}
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
+/* Enable polling stats and return whether they were already enabled. */
+static bool blk_poll_stats_enable(struct request_queue *q)
+{
+ if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
+ test_and_set_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
+ return true;
+ blk_stat_add_callback(q, q->poll_cb);
+ return false;
+}
+
+static void blk_mq_poll_stats_start(struct request_queue *q)
+{
+ /*
+ * We don't arm the callback if polling stats are not enabled or the
+ * callback is already active.
+ */
+ if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
+ blk_stat_is_active(q->poll_cb))
+ return;
+
+ blk_stat_activate_msecs(q->poll_cb, 100);
+}
+
+static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
+{
+ struct request_queue *q = cb->data;
+ int bucket;
+
+ for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) {
+ if (cb->stat[bucket].nr_samples)
+ q->poll_stat[bucket] = cb->stat[bucket];
+ }
+}
+
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
- struct blk_rq_stat stat[2];
unsigned long ret = 0;
+ int bucket;
/*
* If stats collection isn't on, don't sleep but turn it on for
* future users
*/
- if (!blk_stat_enable(q))
+ if (!blk_poll_stats_enable(q))
return 0;
- /*
- * We don't have to do this once per IO, should optimize this
- * to just use the current window of stats until it changes
- */
- memset(&stat, 0, sizeof(stat));
- blk_hctx_stat_get(hctx, stat);
-
/*
* As an optimistic guess, use half of the mean service time
* for this type of request. We can (and should) make this smarter.
* For instance, if the completion latencies are tight, we can
* get closer than just half the mean. This is especially
* important on devices where the completion latencies are longer
- * than ~10 usec.
+ * than ~10 usec. We do use the stats for the relevant IO size
+ * if available which does lead to better estimates.
*/
- if (req_op(rq) == REQ_OP_READ && stat[BLK_STAT_READ].nr_samples)
- ret = (stat[BLK_STAT_READ].mean + 1) / 2;
- else if (req_op(rq) == REQ_OP_WRITE && stat[BLK_STAT_WRITE].nr_samples)
- ret = (stat[BLK_STAT_WRITE].mean + 1) / 2;
+ bucket = blk_mq_poll_stats_bkt(rq);
+ if (bucket < 0)
+ return ret;
+
+ if (q->poll_stat[bucket].nr_samples)
+ ret = (q->poll_stat[bucket].mean + 1) / 2;
return ret;
}
projects / karo-tx-linux.git / blobdiff