diff options
| author | Jens Axboe <axboe@kernel.dk> | 2019-12-07 21:06:46 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-12-10 16:33:22 -0700 |
| commit | e995d5123ed433e37a8d63ac528737c912592e3d (patch) | |
| tree | 2e3608cdb19631f901bf40a92adc5e74934cdaf8 | |
| parent | 506d95ff5d6aa0a099a116c49d3884e29801d843 (diff) | |
io-wq: briefly spin for new work after finishing work
To avoid going to sleep only to get woken shortly thereafter, spin
briefly for new work upon completion of work.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/io-wq.c | 24 | ||||
| -rw-r--r-- | fs/io-wq.h | 7 |
2 files changed, 26 insertions, 5 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c index 6b663ddceb42..90c4978781fb 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -491,26 +491,46 @@ next: } while (1); } +static inline void io_worker_spin_for_work(struct io_wqe *wqe) +{ + int i = 0; + + while (++i < 1000) { + if (io_wqe_run_queue(wqe)) + break; + if (need_resched()) + break; + cpu_relax(); + } +} + static int io_wqe_worker(void *data) { struct io_worker *worker = data; struct io_wqe *wqe = worker->wqe; struct io_wq *wq = wqe->wq; + bool did_work; io_worker_start(wqe, worker); + did_work = false; while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { set_current_state(TASK_INTERRUPTIBLE); +loop: + if (did_work) + io_worker_spin_for_work(wqe); spin_lock_irq(&wqe->lock); if (io_wqe_run_queue(wqe)) { __set_current_state(TASK_RUNNING); io_worker_handle_work(worker); - continue; + did_work = true; + goto loop; } + did_work = false; /* drops the lock on success, retry */ if (__io_worker_idle(wqe, worker)) { __release(&wqe->lock); - continue; + goto loop; } spin_unlock_irq(&wqe->lock); if (signal_pending(current)) diff --git a/fs/io-wq.h b/fs/io-wq.h index 7c333a28e2a7..fb993b2bd0ef 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -35,7 +35,8 @@ static inline void wq_list_add_tail(struct io_wq_work_node *node, struct io_wq_work_list *list) { if (!list->first) { - list->first = list->last = node; + list->last = node; + WRITE_ONCE(list->first, node); } else { list->last->next = node; list->last = node; @@ -47,7 +48,7 @@ static inline void wq_node_del(struct io_wq_work_list *list, struct io_wq_work_node *prev) { if (node == list->first) - list->first = node->next; + WRITE_ONCE(list->first, node->next); if (node == list->last) list->last = prev; if (prev) @@ -58,7 +59,7 @@ static inline void wq_node_del(struct io_wq_work_list *list, #define wq_list_for_each(pos, prv, head) \ for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next) -#define wq_list_empty(list) ((list)->first == NULL) +#define wq_list_empty(list) (READ_ONCE((list)->first) == NULL) #define INIT_WQ_LIST(list) do { \ (list)->first = NULL; \ (list)->last = NULL; \ |