From e944475e69849273ca8f1fe04a3ce81b5901d165 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 26 Nov 2019 15:02:04 -0700 Subject: io_uring: make poll->wait dynamically allocated In the quest to bring io_kiocb down to 3 cachelines, this one does the trick. Make the wait_queue_entry for the poll command come out of kmalloc instead of embedding it in struct io_poll_iocb, as the latter is the largest member of io_kiocb. Once we trim this down a bit, we're back at a healthy 192 bytes for struct io_kiocb. Signed-off-by: Jens Axboe --- fs/io_uring.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index e44b0e01f1b5..2c2e8c25da01 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -291,7 +291,7 @@ struct io_poll_iocb { __poll_t events; bool done; bool canceled; - struct wait_queue_entry wait; + struct wait_queue_entry *wait; }; struct io_timeout_data { @@ -2030,8 +2030,8 @@ static void io_poll_remove_one(struct io_kiocb *req) spin_lock(&poll->head->lock); WRITE_ONCE(poll->canceled, true); - if (!list_empty(&poll->wait.entry)) { - list_del_init(&poll->wait.entry); + if (!list_empty(&poll->wait->entry)) { + list_del_init(&poll->wait->entry); io_queue_async_work(req); } spin_unlock(&poll->head->lock); @@ -2104,6 +2104,7 @@ static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) struct io_ring_ctx *ctx = req->ctx; req->poll.done = true; + kfree(req->poll.wait); if (error) io_cqring_fill_event(req, error); else @@ -2141,7 +2142,7 @@ static void io_poll_complete_work(struct io_wq_work **workptr) */ spin_lock_irq(&ctx->completion_lock); if (!mask && ret != -ECANCELED) { - add_wait_queue(poll->head, &poll->wait); + add_wait_queue(poll->head, poll->wait); spin_unlock_irq(&ctx->completion_lock); return; } @@ -2161,8 +2162,7 @@ static void io_poll_complete_work(struct io_wq_work **workptr) static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { - struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb, - wait); + struct io_poll_iocb *poll = wait->private; struct io_kiocb *req = container_of(poll, struct io_kiocb, poll); struct io_ring_ctx *ctx = req->ctx; __poll_t mask = key_to_poll(key); @@ -2172,7 +2172,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, if (mask && !(mask & poll->events)) return 0; - list_del_init(&poll->wait.entry); + list_del_init(&poll->wait->entry); /* * Run completion inline if we can. We're using trylock here because @@ -2213,7 +2213,7 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, pt->error = 0; pt->req->poll.head = head; - add_wait_queue(head, &pt->req->poll.wait); + add_wait_queue(head, pt->req->poll.wait); } static void io_poll_req_insert(struct io_kiocb *req) @@ -2252,6 +2252,10 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (!poll->file) return -EBADF; + poll->wait = kmalloc(sizeof(*poll->wait), GFP_KERNEL); + if (!poll->wait) + return -ENOMEM; + req->sqe = NULL; INIT_IO_WORK(&req->work, io_poll_complete_work); events = READ_ONCE(sqe->poll_events); @@ -2268,8 +2272,9 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ /* initialized the list so that we can do list_empty checks */ - INIT_LIST_HEAD(&poll->wait.entry); - init_waitqueue_func_entry(&poll->wait, io_poll_wake); + INIT_LIST_HEAD(&poll->wait->entry); + init_waitqueue_func_entry(poll->wait, io_poll_wake); + poll->wait->private = poll; INIT_LIST_HEAD(&req->list); @@ -2278,14 +2283,14 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, spin_lock_irq(&ctx->completion_lock); if (likely(poll->head)) { spin_lock(&poll->head->lock); - if (unlikely(list_empty(&poll->wait.entry))) { + if (unlikely(list_empty(&poll->wait->entry))) { if (ipt.error) cancel = true; ipt.error = 0; mask = 0; } if (mask || ipt.error) - list_del_init(&poll->wait.entry); + list_del_init(&poll->wait->entry); else if (cancel) WRITE_ONCE(poll->canceled, true); else if (!poll->done) /* actually waiting for an event */ -- cgit v1.2.3-59-g8ed1b