From: Stefan Roesch <shr@xxxxxxxxxxxx> This adds the napi_busy_loop_rcu() function. This function assumes that the calling function is already holding the rcu read lock and napi_busy_loop() does not need to take the rcu read lock. Add a NAPI_F_NO_SCHED flag, which tells __napi_busy_loop() to abort if we need to reschedule rather than drop the RCU read lock and reschedule. Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230608163839.2891748-3-shr@xxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> --- include/net/busy_poll.h | 4 ++++ net/core/dev.c | 15 +++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/net/busy_poll.h b/include/net/busy_poll.h index 4dabeb6c76d3..9b09acac538e 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -48,6 +48,10 @@ void napi_busy_loop(unsigned int napi_id, bool (*loop_end)(void *, unsigned long), void *loop_end_arg, bool prefer_busy_poll, u16 budget); +void napi_busy_loop_rcu(unsigned int napi_id, + bool (*loop_end)(void *, unsigned long), + void *loop_end_arg, bool prefer_busy_poll, u16 budget); + #else /* CONFIG_NET_RX_BUSY_POLL */ static inline unsigned long net_busy_loop_on(void) { diff --git a/net/core/dev.c b/net/core/dev.c index 1eaed657f2c2..ffa394f3e796 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6179,6 +6179,7 @@ static void __busy_poll_stop(struct napi_struct *napi, bool skip_schedule) enum { NAPI_F_PREFER_BUSY_POLL = 1, + NAPI_F_END_ON_RESCHED = 2, }; static void busy_poll_stop(struct napi_struct *napi, void *have_poll_lock, @@ -6285,6 +6286,8 @@ static void __napi_busy_loop(unsigned int napi_id, break; if (unlikely(need_resched())) { + if (flags & NAPI_F_END_ON_RESCHED) + break; if (napi_poll) busy_poll_stop(napi, have_poll_lock, flags, budget); if (!IS_ENABLED(CONFIG_PREEMPT_RT)) @@ -6304,6 +6307,18 @@ static void __napi_busy_loop(unsigned int napi_id, preempt_enable(); } +void napi_busy_loop_rcu(unsigned int napi_id, + bool (*loop_end)(void *, unsigned long), + void *loop_end_arg, bool prefer_busy_poll, u16 budget) +{ + unsigned flags = NAPI_F_END_ON_RESCHED; + + if (prefer_busy_poll) + flags |= NAPI_F_PREFER_BUSY_POLL; + + __napi_busy_loop(napi_id, loop_end, loop_end_arg, flags, budget); +} + void napi_busy_loop(unsigned int napi_id, bool (*loop_end)(void *, unsigned long), void *loop_end_arg, bool prefer_busy_poll, u16 budget) -- 2.43.0
