Commit 37112105 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <>
Signed-off-by: default avatarDavid S. Miller <>
parent bc135b23
......@@ -23,11 +23,17 @@ struct qdisc_rate_table {
enum qdisc_state_t {
* following bits are only changed while qdisc lock is held
enum qdisc___state_t {
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 {
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