From 1f5324a0faa7cf906bece9b0df383b5f7ad602aa Mon Sep 17 00:00:00 2001 From: Corey Hickey Date: Sun, 28 Oct 2007 16:59:28 -0700 Subject: [PATCH 07/10] Rework perturb_period. perturb_period is the only parameter that doesn't match 1:1 with the value from userspace. Multiplying perturb_period by HZ when used rather than when assigned makes it easy and clean to use a small function for setting parameters (in a subsequent patch). perturb_period is currently a signed integer, but I can't see any good reason why this is so--a negative perturbation period will add a timer that expires in the past, causing constant perturbation, which makes hashing useless. Strictly speaking, this will break binary compatibility with older versions of tc, but that ought not to be a problem because (a) there's no valid use for a negative perturb_period, and (b) negative values will be seen as high values (> INT_MAX), which don't work anyway. Signed-off-by: Corey Hickey --- include/linux/pkt_sched.h | 2 +- net/sched/sch_sfq.c | 14 ++++++++------ 2 files changed, 9 insertions(+), 7 deletions(-) diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h index d754a3d..14a08ad 100644 --- a/include/linux/pkt_sched.h +++ b/include/linux/pkt_sched.h @@ -142,7 +142,7 @@ enum struct tc_sfq_qopt { unsigned quantum; /* Bytes per round allocated to flow */ - int perturb_period; /* Period of hash perturbation */ + unsigned perturb_period; /* Period of hash perturbation */ __u32 limit; /* Maximal packets in queue */ unsigned divisor; /* Hash divisor */ unsigned flows; /* Maximal number of flows */ diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index 7b11086..2764a54 100644 --- a/net/sched/sch_sfq.c +++ b/net/sched/sch_sfq.c @@ -70,6 +70,8 @@ #define SFQ_HEAD 0 #define SFQ_TAIL 1 +#define SFQ_PERTURB(period) (jiffies + (unsigned long)period * HZ) + /* This type must contain greater than depth*2 values, so depth is constrained * accordingly. */ typedef unsigned int sfq_index; @@ -88,7 +90,7 @@ struct sfq_head struct sfq_sched_data { /* Parameters */ - int perturb_period; + unsigned perturb_period; unsigned quantum; /* Allotment per round: MUST BE >= MTU */ int limit; unsigned depth; @@ -409,7 +411,7 @@ static void sfq_perturbation(unsigned long arg) get_random_bytes(&q->perturbation, 4); if (q->perturb_period) - mod_timer(&q->perturb_timer, jiffies + q->perturb_period); + mod_timer(&q->perturb_timer, SFQ_PERTURB(q->perturb_period)); } static void sfq_q_destroy(struct sfq_sched_data *q) @@ -471,7 +473,7 @@ sfq_q_init(struct sfq_sched_data *q, struct rtattr *opt) if (ctl->quantum) q->quantum = ctl->quantum; if (ctl->perturb_period) - q->perturb_period = ctl->perturb_period * HZ; + q->perturb_period = ctl->perturb_period; if (ctl->divisor) q->hash_divisor = ctl->divisor; if (ctl->flows) @@ -535,7 +537,7 @@ static int sfq_init(struct Qdisc *sch, struct rtattr *opt) q->perturb_timer.data = (unsigned long)sch; q->perturb_timer.function = sfq_perturbation; if (q->perturb_period) { - q->perturb_timer.expires = jiffies + q->perturb_period; + q->perturb_timer.expires = SFQ_PERTURB(q->perturb_period); add_timer(&q->perturb_timer); } @@ -565,7 +567,7 @@ static int sfq_change(struct Qdisc *sch, struct rtattr *opt) tmp.perturbation = 0; del_timer(&q->perturb_timer); } else if (tmp.perturb_period != q->perturb_period) { - mod_timer(&q->perturb_timer, jiffies + tmp.perturb_period); + mod_timer(&q->perturb_timer, SFQ_PERTURB(tmp.perturb_period)); } /* move packets from the old queue to the tmp queue */ @@ -603,7 +605,7 @@ static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb) struct tc_sfq_qopt opt; opt.quantum = q->quantum; - opt.perturb_period = q->perturb_period/HZ; + opt.perturb_period = q->perturb_period; opt.limit = q->limit; opt.divisor = q->hash_divisor; -- 1.5.3.8