First step for gact RCU operation :
Instead of testing if tcfg_pval is zero or not, just make it 1.
No change in behavior, but slightly faster code.
The smp_rmb()/smp_wmb() barriers, while not strictly needed at this
stage are added for upcoming spinlock removal.
Signed-off-by: Eric Dumazet <eduma...@google.com>
Acked-by: Alexei Starovoitov <a...@plumgrid.com>
Acked-by: Jamal Hadi Salim <j...@mojatatu.com>
Acked-by: John Fastabend <john.fastab...@gmail.com>
---
net/sched/act_gact.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index a4f8af29ee30..22a3a61aa090 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -28,14 +28,16 @@
#ifdef CONFIG_GACT_PROB
static int gact_net_rand(struct tcf_gact *gact)
{
- if (!gact->tcfg_pval || prandom_u32() % gact->tcfg_pval)
+ smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
+ if (prandom_u32() % gact->tcfg_pval)
return gact->tcf_action;
return gact->tcfg_paction;
}
static int gact_determ(struct tcf_gact *gact)
{
- if (!gact->tcfg_pval || gact->tcf_bstats.packets % gact->tcfg_pval)
+ smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
+ if (gact->tcf_bstats.packets % gact->tcfg_pval)
return gact->tcf_action;
return gact->tcfg_paction;
}
@@ -105,7 +107,11 @@ static int tcf_gact_init(struct net *net, struct nlattr
*nla,
#ifdef CONFIG_GACT_PROB
if (p_parm) {
gact->tcfg_paction = p_parm->paction;
- gact->tcfg_pval = p_parm->pval;
+ gact->tcfg_pval = max_t(u16, 1, p_parm->pval);
+ /* Make sure tcfg_pval is written before tcfg_ptype
+ * coupled with smp_rmb() in gact_net_rand() & gact_determ()
+ */
+ smp_wmb();
gact->tcfg_ptype = p_parm->ptype;
}
#endif
--
2.4.3.573.g4eafbef
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