From d5cce407e4f59b2e08d03e29d2b3c55deacc1d48 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 7 Aug 2024 15:18:12 +0100 Subject: [PATCH] io_uring/napi: postpone napi timeout adjustment Remove io_napi_adjust_timeout() and move the adjustments out of the common path into __io_napi_busy_loop(). Now the limit it's calculated based on struct io_wait_queue::timeout, for which we query current time another time. The overhead shouldn't be a problem, it's a polling path, however that can be optimised later by additionally saving the delta time value in io_cqring_wait(). Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/88e14686e245b3b42ff90a3c4d70895d48676206.1723039801.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 1 - io_uring/napi.c | 28 +++++++--------------------- io_uring/napi.h | 16 ---------------- 3 files changed, 7 insertions(+), 38 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 3942db160f18..9ec07f76ad19 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2423,7 +2423,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, dt = timespec64_to_ktime(ts); iowq.timeout = ktime_add(dt, ktime_get()); - io_napi_adjust_timeout(ctx, &iowq, dt); } if (sig) { diff --git a/io_uring/napi.c b/io_uring/napi.c index 64fbbceba980..d78fcbecdd27 100644 --- a/io_uring/napi.c +++ b/io_uring/napi.c @@ -269,27 +269,6 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg) return 0; } -/* - * __io_napi_adjust_timeout() - adjust busy loop timeout - * @ctx: pointer to io-uring context structure - * @iowq: pointer to io wait queue - * @ts: pointer to timespec or NULL - * - * Adjust the busy loop timeout according to timespec and busy poll timeout. - * If the specified NAPI timeout is bigger than the wait timeout, then adjust - * the NAPI timeout accordingly. - */ -void __io_napi_adjust_timeout(struct io_ring_ctx *ctx, struct io_wait_queue *iowq, - ktime_t to_wait) -{ - ktime_t poll_dt = READ_ONCE(ctx->napi_busy_poll_dt); - - if (to_wait) - poll_dt = min(poll_dt, to_wait); - - iowq->napi_busy_poll_dt = poll_dt; -} - /* * __io_napi_busy_loop() - execute busy poll loop * @ctx: pointer to io-uring context structure @@ -302,6 +281,13 @@ void __io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq) if (ctx->flags & IORING_SETUP_SQPOLL) return; + iowq->napi_busy_poll_dt = READ_ONCE(ctx->napi_busy_poll_dt); + if (iowq->timeout != KTIME_MAX) { + ktime_t dt = ktime_sub(iowq->timeout, ktime_get()); + + iowq->napi_busy_poll_dt = min_t(u64, iowq->napi_busy_poll_dt, dt); + } + iowq->napi_prefer_busy_poll = READ_ONCE(ctx->napi_prefer_busy_poll); io_napi_blocking_busy_loop(ctx, iowq); } diff --git a/io_uring/napi.h b/io_uring/napi.h index 27b88c3eb428..fd275ef0456d 100644 --- a/io_uring/napi.h +++ b/io_uring/napi.h @@ -17,8 +17,6 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg); void __io_napi_add(struct io_ring_ctx *ctx, struct socket *sock); -void __io_napi_adjust_timeout(struct io_ring_ctx *ctx, - struct io_wait_queue *iowq, ktime_t to_wait); void __io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq); int io_napi_sqpoll_busy_poll(struct io_ring_ctx *ctx); @@ -27,15 +25,6 @@ static inline bool io_napi(struct io_ring_ctx *ctx) return !list_empty(&ctx->napi_list); } -static inline void io_napi_adjust_timeout(struct io_ring_ctx *ctx, - struct io_wait_queue *iowq, - ktime_t to_wait) -{ - if (!io_napi(ctx)) - return; - __io_napi_adjust_timeout(ctx, iowq, to_wait); -} - static inline void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq) { @@ -86,11 +75,6 @@ static inline bool io_napi(struct io_ring_ctx *ctx) static inline void io_napi_add(struct io_kiocb *req) { } -static inline void io_napi_adjust_timeout(struct io_ring_ctx *ctx, - struct io_wait_queue *iowq, - ktime_t to_wait) -{ -} static inline void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq) {