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authorPaolo Abeni <pabeni@redhat.com>2018-05-25 16:28:44 +0200
committerDavid S. Miller <davem@davemloft.net>2018-05-28 23:13:39 -0400
commite9be0e993d95adbe5efe0e0f03b2a3e71f5bb2b6 (patch)
tree59c29c303e00e10e68efc5c048f1bd1b239ec12e /include/net
parent102cd909635612c0be784a519651954a7924c786 (diff)
net: sched: shrink struct Qdisc
The struct Qdisc has a lot of holes, especially after commit a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback"), which as a side effect, moved the fields just after 'busylock' on a new cacheline. Since both 'padded' and 'refcnt' are not updated frequently, and there is a hole before 'gso_skb', we can move such fields there, saving a cacheline without any performance side effect. Before this commit: pahole -C Qdisc net/sche/sch_generic.o # ... /* size: 384, cachelines: 6, members: 25 */ /* sum members: 236, holes: 3, sum holes: 92 */ /* padding: 56 */ After this commit: pahole -C Qdisc net/sche/sch_generic.o # ... /* size: 320, cachelines: 5, members: 25 */ /* sum members: 236, holes: 2, sum holes: 28 */ /* padding: 56 */ Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/sch_generic.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 98c10a28cd01..827a3711dc68 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -85,6 +85,8 @@ struct Qdisc {
struct net_rate_estimator __rcu *rate_est;
struct gnet_stats_basic_cpu __percpu *cpu_bstats;
struct gnet_stats_queue __percpu *cpu_qstats;
+ int padded;
+ refcount_t refcnt;
/*
* For performance sake on SMP, we put highly modified fields at the end
@@ -97,8 +99,6 @@ struct Qdisc {
unsigned long state;
struct Qdisc *next_sched;
struct sk_buff_head skb_bad_txq;
- int padded;
- refcount_t refcnt;
spinlock_t busylock ____cacheline_aligned_in_smp;
spinlock_t seqlock;