From 819bbaefeded93df36d71d58d9963d706e6e99e1 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Thu, 12 Jun 2025 18:02:25 +0200 Subject: libeth: xdp: add XDPSQ cleanup timers When XDP Tx queues are not interrupt-driven but use lazy cleaning, i.e. only when there are less than `threshold` free descriptors left, we also need cleanup timers to avoid &xdp_buff and &xdp_frame stall for too long, especially with Page Pool (it warns every about inflight pages every 60 second). Let's say we sent 256 frames and don't need to send more, but we clean only when the number of pending items >= 384. In that case, those 256 will stall until 128 more are sent. For this, add simple helpers to run a timer which will clean the queue regardless, after 1 second of the last send. The timer is triggered when finalizing the queue. As long as there is regular active traffic, the timer doesn't fire. Signed-off-by: Alexander Lobakin Reviewed-by: Maciej Fijalkowski Signed-off-by: Tony Nguyen --- include/net/libeth/xdp.h | 57 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) (limited to 'include/net/libeth/xdp.h') diff --git a/include/net/libeth/xdp.h b/include/net/libeth/xdp.h index 20977fdfd6c9..22bd038decb6 100644 --- a/include/net/libeth/xdp.h +++ b/include/net/libeth/xdp.h @@ -177,6 +177,63 @@ static inline void libeth_xdpsq_unlock(struct libeth_xdpsq_lock *lock) __libeth_xdpsq_unlock(lock); } +/* XDPSQ clean-up timers */ + +void libeth_xdpsq_init_timer(struct libeth_xdpsq_timer *timer, void *xdpsq, + struct libeth_xdpsq_lock *lock, + void (*poll)(struct work_struct *work)); + +/** + * libeth_xdpsq_deinit_timer - deinitialize &libeth_xdpsq_timer + * @timer: timer to deinitialize + * + * Flush and disable the underlying workqueue. + */ +static inline void libeth_xdpsq_deinit_timer(struct libeth_xdpsq_timer *timer) +{ + cancel_delayed_work_sync(&timer->dwork); +} + +/** + * libeth_xdpsq_queue_timer - run &libeth_xdpsq_timer + * @timer: timer to queue + * + * Should be called after the queue was filled and the transmission was run + * to complete the pending buffers if no further sending will be done in a + * second (-> lazy cleaning won't happen). + * If the timer was already run, it will be requeued back to one second + * timeout again. + */ +static inline void libeth_xdpsq_queue_timer(struct libeth_xdpsq_timer *timer) +{ + mod_delayed_work_on(raw_smp_processor_id(), system_bh_highpri_wq, + &timer->dwork, HZ); +} + +/** + * libeth_xdpsq_run_timer - wrapper to run a queue clean-up on a timer event + * @work: workqueue belonging to the corresponding timer + * @poll: driver-specific completion queue poll function + * + * Run the polling function on the locked queue and requeue the timer if + * there's more work to do. + * Designed to be used via LIBETH_XDP_DEFINE_TIMER() below. + */ +static __always_inline void +libeth_xdpsq_run_timer(struct work_struct *work, + u32 (*poll)(void *xdpsq, u32 budget)) +{ + struct libeth_xdpsq_timer *timer = container_of(work, typeof(*timer), + dwork.work); + + libeth_xdpsq_lock(timer->lock); + + if (poll(timer->xdpsq, U32_MAX)) + libeth_xdpsq_queue_timer(timer); + + libeth_xdpsq_unlock(timer->lock); +} + /* Common Tx bits */ /** -- cgit v1.2.3