From dbc2564cfe0faff439dc46adb8c009589054ea46 Mon Sep 17 00:00:00 2001 From: Hao Xu Date: Sat, 14 May 2022 22:20:45 +0800 Subject: [PATCH] io_uring: let fast poll support multishot For operations like accept, multishot is a useful feature, since we can reduce a number of accept sqe. Let's integrate it to fast poll, it may be good for other operations in the future. Signed-off-by: Hao Xu Link: https://lore.kernel.org/r/20220514142046.58072-4-haoxu.linux@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 47 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index e1e550de5956..a83405f657e0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6011,6 +6011,7 @@ static void io_poll_remove_entries(struct io_kiocb *req) rcu_read_unlock(); } +static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags); /* * All poll tw should go through this. Checks for poll events, manages * references, does rewait, etc. @@ -6019,10 +6020,10 @@ static void io_poll_remove_entries(struct io_kiocb *req) * either spurious wakeup or multishot CQE is served. 0 when it's done with * the request, then the mask is stored in req->cqe.res. */ -static int io_poll_check_events(struct io_kiocb *req, bool locked) +static int io_poll_check_events(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; - int v; + int v, ret; /* req->task == current here, checking PF_EXITING is safe */ if (unlikely(req->task->flags & PF_EXITING)) @@ -6046,23 +6047,37 @@ static int io_poll_check_events(struct io_kiocb *req, bool locked) req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events; } - /* multishot, just fill an CQE and proceed */ - if (req->cqe.res && !(req->apoll_events & EPOLLONESHOT)) { - __poll_t mask = mangle_poll(req->cqe.res & req->apoll_events); + if ((unlikely(!req->cqe.res))) + continue; + if (req->apoll_events & EPOLLONESHOT) + return 0; + + /* multishot, just fill a CQE and proceed */ + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) { + __poll_t mask = mangle_poll(req->cqe.res & + req->apoll_events); bool filled; spin_lock(&ctx->completion_lock); - filled = io_fill_cqe_aux(ctx, req->cqe.user_data, mask, - IORING_CQE_F_MORE); + filled = io_fill_cqe_aux(ctx, req->cqe.user_data, + mask, IORING_CQE_F_MORE); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); - if (unlikely(!filled)) - return -ECANCELED; - io_cqring_ev_posted(ctx); - } else if (req->cqe.res) { - return 0; + if (filled) { + io_cqring_ev_posted(ctx); + continue; + } + return -ECANCELED; } + io_tw_lock(req->ctx, locked); + if (unlikely(req->task->flags & PF_EXITING)) + return -EFAULT; + ret = io_issue_sqe(req, + IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER); + if (ret) + return ret; + /* * Release all references, retry if someone tried to restart * task_work while we were executing it. @@ -6077,7 +6092,7 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) struct io_ring_ctx *ctx = req->ctx; int ret; - ret = io_poll_check_events(req, *locked); + ret = io_poll_check_events(req, locked); if (ret > 0) return; @@ -6102,7 +6117,7 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) struct io_ring_ctx *ctx = req->ctx; int ret; - ret = io_poll_check_events(req, *locked); + ret = io_poll_check_events(req, locked); if (ret > 0) return; @@ -6343,7 +6358,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; - __poll_t mask = IO_ASYNC_POLL_COMMON | POLLERR; + __poll_t mask = POLLPRI | POLLERR; int ret; if (!def->pollin && !def->pollout) @@ -6352,6 +6367,8 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) return IO_APOLL_ABORTED; if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED) return IO_APOLL_ABORTED; + if (!(req->flags & REQ_F_APOLL_MULTISHOT)) + mask |= EPOLLONESHOT; if (def->pollin) { mask |= POLLIN | POLLRDNORM; -- 2.20.1