From 03e02acda8e267a8183e1e0ed289ff1ef9cd7ed8 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 20 Nov 2022 10:13:44 -0700 Subject: eventfd: provide a eventfd_signal_mask() helper This is identical to eventfd_signal(), but it allows the caller to pass in a mask to be used for the poll wakeup key. The use case is avoiding repeated multishot triggers if we have a dependency between eventfd and io_uring. If we setup an eventfd context and register that as the io_uring eventfd, and at the same time queue a multishot poll request for the eventfd context, then any CQE posted will repeatedly trigger the multishot request until it terminates when the CQ ring overflows. In preparation for io_uring detecting this circular dependency, add the mentioned helper so that io_uring can pass in EPOLL_URING as part of the poll wakeup key. Cc: stable@vger.kernel.org # 6.0 [axboe: fold in !CONFIG_EVENTFD fix from Zhang Qilong] Signed-off-by: Jens Axboe --- include/linux/eventfd.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index 30eb30d6909b..786824f58d3d 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -40,6 +40,7 @@ struct file *eventfd_fget(int fd); struct eventfd_ctx *eventfd_ctx_fdget(int fd); struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, unsigned mask); int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, __u64 *cnt); void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); @@ -66,6 +67,12 @@ static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) return -ENOSYS; } +static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, + unsigned mask) +{ + return -ENOSYS; +} + static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) { -- cgit v1.2.3 From 931147ddfa6e9ffd814272f1c0370c4740acbe17 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 24 Nov 2022 01:35:54 -0800 Subject: io_uring: allow defer completion for aux posted cqes Multishot ops cannot use the compl_reqs list as the request must stay in the poll list, but that means they need to run each completion without benefiting from batching. Here introduce batching infrastructure for only small (ie 16 byte) CQEs. This restriction is ok because there are no use cases posting 32 byte CQEs. In the ring keep a batch of up to 16 posted results, and flush in the same way as compl_reqs. 16 was chosen through experimentation on a microbenchmark ([1]), as well as trying not to increase the size of the ring too much. This increases the size to 1472 bytes from 1216. [1]: https://github.com/DylanZA/liburing/commit/9ac66b36bcf4477bfafeff1c5f107896b7ae31cf Run with $ make -j && ./benchmark/reg.b -s 1 -t 2000 -r 10 Gives results: baseline 8309 k/s 8 18807 k/s 16 19338 k/s 32 20134 k/s Suggested-by: Pavel Begunkov Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20221124093559.3780686-5-dylany@meta.com Signed-off-by: Jens Axboe --- include/linux/io_uring_types.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index f5b687a787a3..accdfecee953 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -174,7 +174,9 @@ struct io_submit_state { bool plug_started; bool need_plug; unsigned short submit_nr; + unsigned int cqes_count; struct blk_plug plug; + struct io_uring_cqe cqes[16]; }; struct io_ev_fd { -- cgit v1.2.3