From 371121057607e3127e19b3fa094330181b5b031e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 2 Jun 2010 03:24:13 -0700 Subject: [PATCH] net: QDISC_STATE_RUNNING dont need atomic bit ops __QDISC_STATE_RUNNING is always changed while qdisc lock is held. We can avoid two atomic operations in xmit path, if we move this bit in a new __state container. Location of this __state container is carefully chosen so that fast path only dirties one qdisc cache line. THROTTLED bit could later be moved into this __state location too, to avoid dirtying first qdisc cache line. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/sch_generic.h | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 9707daed761e..b3591e4a514c 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -23,11 +23,17 @@ struct qdisc_rate_table { }; enum qdisc_state_t { - __QDISC_STATE_RUNNING, __QDISC_STATE_SCHED, __QDISC_STATE_DEACTIVATED, }; +/* + * following bits are only changed while qdisc lock is held + */ +enum qdisc___state_t { + __QDISC___STATE_RUNNING, +}; + struct qdisc_size_table { struct list_head list; struct tc_sizespec szopts; @@ -72,23 +78,24 @@ struct Qdisc { unsigned long state; struct sk_buff_head q; struct gnet_stats_basic_packed bstats; + unsigned long __state; struct gnet_stats_queue qstats; struct rcu_head rcu_head; }; static inline bool qdisc_is_running(struct Qdisc *qdisc) { - return test_bit(__QDISC_STATE_RUNNING, &qdisc->state); + return test_bit(__QDISC___STATE_RUNNING, &qdisc->__state); } static inline bool qdisc_run_begin(struct Qdisc *qdisc) { - return !test_and_set_bit(__QDISC_STATE_RUNNING, &qdisc->state); + return !__test_and_set_bit(__QDISC___STATE_RUNNING, &qdisc->__state); } static inline void qdisc_run_end(struct Qdisc *qdisc) { - clear_bit(__QDISC_STATE_RUNNING, &qdisc->state); + __clear_bit(__QDISC___STATE_RUNNING, &qdisc->__state); } struct Qdisc_class_ops { -- 2.20.1