Commit 3fcbecbd authored by Martin Karsten's avatar Martin Karsten Committed by Jakub Kicinski
Browse files

net: Add control functions for irq suspension 



The napi_suspend_irqs routine bootstraps irq suspension by elongating
the defer timeout to irq_suspend_timeout.

The napi_resume_irqs routine effectively cancels irq suspension by
forcing the napi to be scheduled immediately.

Signed-off-by: default avatarMartin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: default avatarJoe Damato <jdamato@fastly.com>
Signed-off-by: default avatarJoe Damato <jdamato@fastly.com>
Tested-by: default avatarJoe Damato <jdamato@fastly.com>
Tested-by: default avatarMartin Karsten <mkarsten@uwaterloo.ca>
Acked-by: default avatarStanislav Fomichev <sdf@fomichev.me>
Reviewed-by: default avatarSridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://patch.msgid.link/20241109050245.191288-3-jdamato@fastly.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5dc51ec8

include/net/busy_poll.h

+3 −0
Original line number Diff line number Diff line
@@ -52,6 +52,9 @@ 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);



void napi_suspend_irqs(unsigned int napi_id);

void napi_resume_irqs(unsigned int napi_id);



#else /* CONFIG_NET_RX_BUSY_POLL */

static inline unsigned long net_busy_loop_on(void)

{

net/core/dev.c

+37 −0
Original line number Diff line number Diff line
@@ -6507,6 +6507,43 @@ void napi_busy_loop(unsigned int napi_id, 
}

EXPORT_SYMBOL(napi_busy_loop);



void napi_suspend_irqs(unsigned int napi_id)

{

	struct napi_struct *napi;



	rcu_read_lock();

	napi = napi_by_id(napi_id);

	if (napi) {

		unsigned long timeout = napi_get_irq_suspend_timeout(napi);



		if (timeout)

			hrtimer_start(&napi->timer, ns_to_ktime(timeout),

				      HRTIMER_MODE_REL_PINNED);

	}

	rcu_read_unlock();

}



void napi_resume_irqs(unsigned int napi_id)

{

	struct napi_struct *napi;



	rcu_read_lock();

	napi = napi_by_id(napi_id);

	if (napi) {

		/* If irq_suspend_timeout is set to 0 between the call to

		 * napi_suspend_irqs and now, the original value still

		 * determines the safety timeout as intended and napi_watchdog

		 * will resume irq processing.

		 */

		if (napi_get_irq_suspend_timeout(napi)) {

			local_bh_disable();

			napi_schedule(napi);

			local_bh_enable();

		}

	}

	rcu_read_unlock();

}



#endif /* CONFIG_NET_RX_BUSY_POLL */



static void __napi_hash_add_with_id(struct napi_struct *napi,