From 9704cfcf1fa9bd7b7a2e7d3adf892baa106d771d Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Sep 2023 14:57:07 +0100 Subject: [PATCH] io_uring/sqpoll: fix io-wq affinity when IORING_SETUP_SQPOLL is used From: Jens Axboe [ upstream commit ebdfefc09c6de7897962769bd3e63a2ff443ebf5 ] If we setup the ring with SQPOLL, then that polling thread has its own io-wq setup. This means that if the application uses IORING_REGISTER_IOWQ_AFF to set the io-wq affinity, we should not be setting it for the invoking task, but rather the sqpoll task. Add an sqpoll helper that parks the thread and updates the affinity, and use that one if we're using SQPOLL. Fixes: fe76421d1da1 ("io_uring: allow user configurable IO thread CPU affinity") Cc: stable@vger.kernel.org # 5.10+ Link: https://github.com/axboe/liburing/discussions/884 Signed-off-by: Jens Axboe Signed-off-by: Pavel Begunkov Signed-off-by: Greg Kroah-Hartman --- io_uring/io-wq.c | 7 +++++-- io_uring/io-wq.h | 2 +- io_uring/io_uring.c | 29 ++++++++++++++++++----------- io_uring/sqpoll.c | 15 +++++++++++++++ io_uring/sqpoll.h | 1 + 5 files changed, 40 insertions(+), 14 deletions(-) diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index dc3d4b8356220d..98ac9dbcec2f5e 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -1350,13 +1350,16 @@ static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node) return __io_wq_cpu_online(wq, cpu, false); } -int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask) +int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask) { int i; + if (!tctx || !tctx->io_wq) + return -EINVAL; + rcu_read_lock(); for_each_node(i) { - struct io_wqe *wqe = wq->wqes[i]; + struct io_wqe *wqe = tctx->io_wq->wqes[i]; if (mask) cpumask_copy(wqe->cpu_mask, mask); diff --git a/io_uring/io-wq.h b/io_uring/io-wq.h index 31cc5cc9048c4a..2b2a6406dd8ee8 100644 --- a/io_uring/io-wq.h +++ b/io_uring/io-wq.h @@ -50,7 +50,7 @@ void io_wq_put_and_exit(struct io_wq *wq); void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work); void io_wq_hash_work(struct io_wq_work *work, void *val); -int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask); +int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask); int io_wq_max_workers(struct io_wq *wq, int *new_count); bool io_wq_worker_stopped(void); diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 7c8e81057eb1b9..f413ebed81ab33 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3835,16 +3835,28 @@ static int io_register_enable_rings(struct io_ring_ctx *ctx) return 0; } +static __cold int __io_register_iowq_aff(struct io_ring_ctx *ctx, + cpumask_var_t new_mask) +{ + int ret; + + if (!(ctx->flags & IORING_SETUP_SQPOLL)) { + ret = io_wq_cpu_affinity(current->io_uring, new_mask); + } else { + mutex_unlock(&ctx->uring_lock); + ret = io_sqpoll_wq_cpu_affinity(ctx, new_mask); + mutex_lock(&ctx->uring_lock); + } + + return ret; +} + static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx, void __user *arg, unsigned len) { - struct io_uring_task *tctx = current->io_uring; cpumask_var_t new_mask; int ret; - if (!tctx || !tctx->io_wq) - return -EINVAL; - if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) return -ENOMEM; @@ -3865,19 +3877,14 @@ static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx, return -EFAULT; } - ret = io_wq_cpu_affinity(tctx->io_wq, new_mask); + ret = __io_register_iowq_aff(ctx, new_mask); free_cpumask_var(new_mask); return ret; } static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx) { - struct io_uring_task *tctx = current->io_uring; - - if (!tctx || !tctx->io_wq) - return -EINVAL; - - return io_wq_cpu_affinity(tctx->io_wq, NULL); + return __io_register_iowq_aff(ctx, NULL); } static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 6ffa5cf1bbb86e..2949959cbe605e 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -423,3 +423,18 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx, io_sq_thread_finish(ctx); return ret; } + +__cold int io_sqpoll_wq_cpu_affinity(struct io_ring_ctx *ctx, + cpumask_var_t mask) +{ + struct io_sq_data *sqd = ctx->sq_data; + int ret = -EINVAL; + + if (sqd) { + io_sq_thread_park(sqd); + ret = io_wq_cpu_affinity(sqd->thread->io_uring, mask); + io_sq_thread_unpark(sqd); + } + + return ret; +} diff --git a/io_uring/sqpoll.h b/io_uring/sqpoll.h index 0c3fbcd1f583f6..36245f1afa5eec 100644 --- a/io_uring/sqpoll.h +++ b/io_uring/sqpoll.h @@ -27,3 +27,4 @@ void io_sq_thread_park(struct io_sq_data *sqd); void io_sq_thread_unpark(struct io_sq_data *sqd); void io_put_sq_data(struct io_sq_data *sqd); int io_sqpoll_wait_sq(struct io_ring_ctx *ctx); +int io_sqpoll_wq_cpu_affinity(struct io_ring_ctx *ctx, cpumask_var_t mask);