From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Stephen Hemminger <stephen.hemminger@vyatta.com>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH 2/2] SFQ: use net_random
Date: Fri, 18 Jan 2008 20:18:20 -0800 [thread overview]
Message-ID: <20080119041820.GA24840@linux.vnet.ibm.com> (raw)
In-Reply-To: <20080118144730.7878f12a@deepthought>
On Fri, Jan 18, 2008 at 02:47:30PM -0800, Stephen Hemminger wrote:
> SFQ doesn't need true random numbers, it is only using them to salt
> a hash. Therefore it is better to use net_random() and avoid any possible
> problems with depleting the entropy pool.
The random-number algorithm used by net_random() certainly does appear
to be considerably stronger than the one I used to generate the results
in the 1990 paper. ;-)
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>
>
>
> --- a/net/sched/sch_sfq.c 2008-01-17 09:00:58.000000000 -0800
> +++ b/net/sched/sch_sfq.c 2008-01-17 09:03:26.000000000 -0800
> @@ -386,7 +386,7 @@ static void sfq_perturbation(unsigned lo
> struct Qdisc *sch = (struct Qdisc*)arg;
> struct sfq_sched_data *q = qdisc_priv(sch);
>
> - get_random_bytes(&q->perturbation, 4);
> + q->perturbation = net_random();
>
> if (q->perturb_period)
> mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
> @@ -415,7 +415,7 @@ static int sfq_change(struct Qdisc *sch,
> del_timer(&q->perturb_timer);
> if (q->perturb_period) {
> mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
> - get_random_bytes(&q->perturbation, 4);
> + q->perturbation = net_random();
> }
> sch_tree_unlock(sch);
> return 0;
> @@ -443,7 +443,7 @@ static int sfq_init(struct Qdisc *sch, s
> if (opt == NULL) {
> q->quantum = psched_mtu(sch->dev);
> q->perturb_period = 0;
> - get_random_bytes(&q->perturbation, 4);
> + q->perturbation = net_random();
> } else {
> int err = sfq_change(sch, opt);
> if (err)
next prev parent reply other threads:[~2008-01-19 4:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080118144309.3530ed2f@deepthought>
[not found] ` <20080118144730.7878f12a@deepthought>
2008-01-19 0:09 ` [PATCH 3/3] sfq: whitespace cleanup Stephen Hemminger
2008-01-19 4:18 ` Paul E. McKenney [this message]
2008-01-21 1:19 ` [PATCH 2/2] SFQ: use net_random David Miller
[not found] ` <20080118144837.0a3593c5@deepthought>
2008-01-21 1:21 ` [PATCH 3/3] sfq: whitespace cleanup David Miller
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