io_uring: use single linked list for iopoll
Use single linked lists for keeping iopoll requests, takes less space, may be faster, but mostly will be of benefit for further patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/314033676b100cd485518c3bc55e1b95a0dcd71f.1632516769.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov
Jens Axboe
parent
e3f721e6f6
commit
5eef4e87eb
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@ -32,6 +32,9 @@ struct io_wq_work_list {
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#define wq_list_for_each(pos, prv, head) \
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for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next)
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#define wq_list_for_each_resume(pos, prv) \
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for (; pos; prv = pos, pos = (pos)->next)
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#define wq_list_empty(list) (READ_ONCE((list)->first) == NULL)
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#define INIT_WQ_LIST(list) do { \
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(list)->first = NULL; \
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@ -412,7 +412,7 @@ struct io_ring_ctx {
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* For SQPOLL, only the single threaded io_sq_thread() will
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* manipulate the list, hence no extra locking is needed there.
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*/
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struct list_head iopoll_list;
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struct io_wq_work_list iopoll_list;
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struct hlist_head *cancel_hash;
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unsigned cancel_hash_bits;
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bool poll_multi_queue;
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@ -1309,7 +1309,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
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init_waitqueue_head(&ctx->cq_wait);
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spin_lock_init(&ctx->completion_lock);
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spin_lock_init(&ctx->timeout_lock);
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INIT_LIST_HEAD(&ctx->iopoll_list);
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INIT_WQ_LIST(&ctx->iopoll_list);
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INIT_LIST_HEAD(&ctx->defer_list);
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INIT_LIST_HEAD(&ctx->timeout_list);
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INIT_LIST_HEAD(&ctx->ltimeout_list);
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@ -2441,15 +2441,9 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, struct list_head *done)
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io_req_free_batch_finish(ctx, &rb);
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}
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/* same as "continue" but starts from the pos, not next to it */
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#define list_for_each_entry_safe_resume(pos, n, head, member) \
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for (n = list_next_entry(pos, member); \
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!list_entry_is_head(pos, head, member); \
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pos = n, n = list_next_entry(n, member))
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static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
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{
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struct io_kiocb *req, *tmp;
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struct io_wq_work_node *pos, *start, *prev;
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unsigned int poll_flags = BLK_POLL_NOSLEEP;
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DEFINE_IO_COMP_BATCH(iob);
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int nr_events = 0;
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@ -2462,7 +2456,8 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
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if (ctx->poll_multi_queue || force_nonspin)
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poll_flags |= BLK_POLL_ONESHOT;
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list_for_each_entry(req, &ctx->iopoll_list, inflight_entry) {
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wq_list_for_each(pos, start, &ctx->iopoll_list) {
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struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
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struct kiocb *kiocb = &req->rw.kiocb;
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int ret;
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@ -2488,14 +2483,20 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
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if (!rq_list_empty(iob.req_list))
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iob.complete(&iob);
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list_for_each_entry_safe_resume(req, tmp, &ctx->iopoll_list,
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inflight_entry) {
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else if (!pos)
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return 0;
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prev = start;
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wq_list_for_each_resume(pos, prev) {
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struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
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if (!READ_ONCE(req->iopoll_completed))
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break;
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list_move_tail(&req->inflight_entry, &done);
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list_add_tail(&req->inflight_entry, &done);
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nr_events++;
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}
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wq_list_cut(&ctx->iopoll_list, prev, start);
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if (nr_events)
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io_iopoll_complete(ctx, &done);
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return nr_events;
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@ -2511,7 +2512,7 @@ static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
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return;
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mutex_lock(&ctx->uring_lock);
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while (!list_empty(&ctx->iopoll_list)) {
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while (!wq_list_empty(&ctx->iopoll_list)) {
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/* let it sleep and repeat later if can't complete a request */
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if (io_do_iopoll(ctx, true) == 0)
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break;
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@ -2560,7 +2561,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
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* forever, while the workqueue is stuck trying to acquire the
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* very same mutex.
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*/
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if (list_empty(&ctx->iopoll_list)) {
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if (wq_list_empty(&ctx->iopoll_list)) {
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u32 tail = ctx->cached_cq_tail;
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mutex_unlock(&ctx->uring_lock);
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@ -2569,7 +2570,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
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/* some requests don't go through iopoll_list */
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if (tail != ctx->cached_cq_tail ||
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list_empty(&ctx->iopoll_list))
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wq_list_empty(&ctx->iopoll_list))
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break;
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}
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ret = io_do_iopoll(ctx, !min);
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@ -2729,14 +2730,13 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
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* how we do polling eventually, not spinning if we're on potentially
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* different devices.
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*/
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if (list_empty(&ctx->iopoll_list)) {
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if (wq_list_empty(&ctx->iopoll_list)) {
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ctx->poll_multi_queue = false;
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} else if (!ctx->poll_multi_queue) {
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struct io_kiocb *list_req;
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list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb,
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inflight_entry);
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list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
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comp_list);
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if (list_req->file != req->file)
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ctx->poll_multi_queue = true;
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}
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@ -2746,9 +2746,9 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
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* it to the front so we find it first.
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*/
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if (READ_ONCE(req->iopoll_completed))
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list_add(&req->inflight_entry, &ctx->iopoll_list);
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wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
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else
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list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
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wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
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if (unlikely(in_async)) {
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/*
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@ -7322,14 +7322,14 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
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if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
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to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
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if (!list_empty(&ctx->iopoll_list) || to_submit) {
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if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
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const struct cred *creds = NULL;
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if (ctx->sq_creds != current_cred())
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creds = override_creds(ctx->sq_creds);
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mutex_lock(&ctx->uring_lock);
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if (!list_empty(&ctx->iopoll_list))
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if (!wq_list_empty(&ctx->iopoll_list))
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io_do_iopoll(ctx, true);
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/*
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@ -7407,7 +7407,7 @@ static int io_sq_thread(void *data)
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list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
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int ret = __io_sq_thread(ctx, cap_entries);
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if (!sqt_spin && (ret > 0 || !list_empty(&ctx->iopoll_list)))
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if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list)))
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sqt_spin = true;
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}
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if (io_run_task_work())
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@ -7428,7 +7428,7 @@ static int io_sq_thread(void *data)
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io_ring_set_wakeup_flag(ctx);
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if ((ctx->flags & IORING_SETUP_IOPOLL) &&
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!list_empty_careful(&ctx->iopoll_list)) {
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!wq_list_empty(&ctx->iopoll_list)) {
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needs_sched = false;
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break;
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}
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@ -9583,7 +9583,7 @@ static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
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/* SQPOLL thread does its own polling */
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if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
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(ctx->sq_data && ctx->sq_data->thread == current)) {
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while (!list_empty_careful(&ctx->iopoll_list)) {
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while (!wq_list_empty(&ctx->iopoll_list)) {
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io_iopoll_try_reap_events(ctx);
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ret = true;
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}
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