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OpenCloudOS-Kernel
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net: sched: remove one pair of atomic operations 

__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 f9eb8aea2a ("net_sched: transform qdisc running bit into a seqcount")

Fixes: 29cbcd8582 ("net: sched: Remove Qdisc::running sequence counter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ahmed S. Darwish <a.darwish@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2021-10-18 17:34:02 -07:00 committed by Jakub Kicinski
parent 4c57e2fac4
commit 97604c65bc
1 changed files with 8 additions and 4 deletions
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12
include/net/sch_generic.h
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@ -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);
}
}