| Message ID | 20110310165328.999266946@vyatta.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On 10/03/11 at 08:51 -0800, Stephen Hemminger wrote: > --- a/net/ipv4/tcp_cubic.c 2011-03-10 08:08:32.867492953 -0800 > +++ b/net/ipv4/tcp_cubic.c 2011-03-10 08:24:39.658201745 -0800 > @@ -342,9 +342,11 @@ static void hystart_update(struct sock * > u32 curr_jiffies = jiffies; > > /* first detection parameter - ack-train detection */ > - if (curr_jiffies - ca->last_jiffies <= msecs_to_jiffies(2)) { > + if ((s32)(curr_jiffies - ca->last_jiffies) <= > + msecs_to_jiffies(2)) { > ca->last_jiffies = curr_jiffies; > - if (curr_jiffies - ca->round_start >= ca->delay_min>>4) > + if ((s32) (curr_jiffies - ca->round_start) <= > + ca->delay_min >> 4) >=, not <=
--- a/net/ipv4/tcp_cubic.c 2011-03-10 08:08:32.867492953 -0800 +++ b/net/ipv4/tcp_cubic.c 2011-03-10 08:24:39.658201745 -0800 @@ -342,9 +342,11 @@ static void hystart_update(struct sock * u32 curr_jiffies = jiffies; /* first detection parameter - ack-train detection */ - if (curr_jiffies - ca->last_jiffies <= msecs_to_jiffies(2)) { + if ((s32)(curr_jiffies - ca->last_jiffies) <= + msecs_to_jiffies(2)) { ca->last_jiffies = curr_jiffies; - if (curr_jiffies - ca->round_start >= ca->delay_min>>4) + if ((s32) (curr_jiffies - ca->round_start) <= + ca->delay_min >> 4) ca->found |= HYSTART_ACK_TRAIN; }
Jiffies wraps around therefore the correct way to compare is to use cast to signed value. Note: cubic is not using full jiffies value on 64 bit arch because using full unsigned long makes struct bictcp grow too large for the available ca_priv area. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html