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net_sched: act_gact: make tcfg_pval non zero

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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 <edumazet@google.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-07-06 05:18:05 -07:00 committed by David S. Miller
parent 519c818e8f
commit cef5ecf96b
1 changed files with 9 additions and 3 deletions
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12
net/sched/act_gact.c
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@ -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