[PATCH net-next 2/2] net: sched: remove one pair of atomic operations
From: Eric Dumazet <hidden>
Date: 2021-10-21 16:23:17
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Eric Dumazet <edumazet@google.com>
__QDISC_STATE_RUNNING is only set/cleared from contexts owning qdisc lock.
Thus we can use less expensive bit operations, as we were doing
before commit f9eb8aea2a1e ("net_sched: transform qdisc running bit into a seqcount")
Fixes: 29cbcd858283 ("net: sched: Remove Qdisc::running sequence counter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ahmed S. Darwish <redacted>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
include/net/sch_generic.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e0988c56dd8fd7aa3dff6bd971da3c81f1a20626..ada02c4a4f518b732d62561a22b1d9033516b494 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h@@ -38,10 +38,13 @@ enum qdisc_state_t { __QDISC_STATE_DEACTIVATED, __QDISC_STATE_MISSED, __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_STATE_RUNNING, + __QDISC_STATE2_RUNNING, }; #define QDISC_STATE_MISSED BIT(__QDISC_STATE_MISSED)
@@ -114,6 +117,7 @@ struct Qdisc { struct gnet_stats_basic_sync bstats; struct gnet_stats_queue qstats; unsigned long state; + unsigned long state2; /* must be written under qdisc spinlock */ struct Qdisc *next_sched; struct sk_buff_head skb_bad_txq;
@@ -154,7 +158,7 @@ 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_STATE_RUNNING, &qdisc->state); + return test_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); } static inline bool nolock_qdisc_is_empty(const struct Qdisc *qdisc)
@@ -217,7 +221,7 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) */ return spin_trylock(&qdisc->seqlock); } - return !test_and_set_bit(__QDISC_STATE_RUNNING, &qdisc->state); + return !__test_and_set_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); } static inline void qdisc_run_end(struct Qdisc *qdisc)
@@ -229,7 +233,7 @@ static inline void qdisc_run_end(struct Qdisc *qdisc) &qdisc->state))) __netif_schedule(qdisc); } else { - clear_bit(__QDISC_STATE_RUNNING, &qdisc->state); + __clear_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); } }
--
2.33.0.1079.g6e70778dc9-goog