Commit 526f5fb1 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: sched: claim one cache line in Qdisc 



Replace state2 field with a boolean.

Move it to a hole between qstats and state so that
we shrink Qdisc by a full cache line.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Tested-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251014171907.3554413-6-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 178ca308

include/net/sch_generic.h

+7 −11
Original line number Diff line number Diff line
@@ -41,13 +41,6 @@ enum qdisc_state_t { 
	__QDISC_STATE_DRAINING,

};



enum qdisc_state2_t {

	/* Only for !TCQ_F_NOLOCK qdisc. Never access it directly.

	 * Use qdisc_run_begin/end() or qdisc_is_running() instead.

	 */

	__QDISC_STATE2_RUNNING,

};



#define QDISC_STATE_MISSED	BIT(__QDISC_STATE_MISSED)

#define QDISC_STATE_DRAINING	BIT(__QDISC_STATE_DRAINING)
@@ -117,8 +110,8 @@ struct Qdisc { 
	struct qdisc_skb_head	q;

	struct gnet_stats_basic_sync bstats;

	struct gnet_stats_queue	qstats;

	bool			running; /* must be written under qdisc spinlock */

	unsigned long		state;

	unsigned long		state2; /* must be written under qdisc spinlock */

	struct Qdisc            *next_sched;

	struct sk_buff_head	skb_bad_txq;
@@ -167,7 +160,7 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc) 
{

	if (qdisc->flags & TCQ_F_NOLOCK)

		return spin_is_locked(&qdisc->seqlock);

	return test_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);

	return READ_ONCE(qdisc->running);

}



static inline bool nolock_qdisc_is_empty(const struct Qdisc *qdisc)
@@ -210,7 +203,10 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) 
		 */

		return spin_trylock(&qdisc->seqlock);

	}

	return !__test_and_set_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);

	if (READ_ONCE(qdisc->running))

		return false;

	WRITE_ONCE(qdisc->running, true);

	return true;

}



static inline void qdisc_run_end(struct Qdisc *qdisc)
@@ -228,7 +224,7 @@ static inline void qdisc_run_end(struct Qdisc *qdisc) 
				      &qdisc->state)))

			__netif_schedule(qdisc);

	} else {

		__clear_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);

		WRITE_ONCE(qdisc->running, false);

	}

}