diff options
Diffstat (limited to 'net/sched/sch_pie.c')
| -rw-r--r-- | net/sched/sch_pie.c | 65 |
1 files changed, 32 insertions, 33 deletions
diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c index d88ab53593b3..30f158582499 100644 --- a/net/sched/sch_pie.c +++ b/net/sched/sch_pie.c @@ -33,7 +33,7 @@ #define QUEUE_THRESHOLD 16384 #define DQCOUNT_INVALID -1 -#define MAX_PROB 0xffffffff +#define MAX_PROB 0xffffffffffffffff #define PIE_SCALE 8 /* parameters used */ @@ -49,7 +49,7 @@ struct pie_params { /* variables used */ struct pie_vars { - u32 prob; /* probability but scaled by u32 limit. */ + u64 prob; /* probability but scaled by u64 limit. */ psched_time_t burst_time; psched_time_t qdelay; psched_time_t qdelay_old; @@ -99,8 +99,8 @@ static void pie_vars_init(struct pie_vars *vars) static bool drop_early(struct Qdisc *sch, u32 packet_size) { struct pie_sched_data *q = qdisc_priv(sch); - u32 rnd; - u32 local_prob = q->vars.prob; + u64 rnd; + u64 local_prob = q->vars.prob; u32 mtu = psched_mtu(qdisc_dev(sch)); /* If there is still burst allowance left skip random early drop */ @@ -124,11 +124,11 @@ static bool drop_early(struct Qdisc *sch, u32 packet_size) * probablity. Smaller packets will have lower drop prob in this case */ if (q->params.bytemode && packet_size <= mtu) - local_prob = (local_prob / mtu) * packet_size; + local_prob = (u64)packet_size * div_u64(local_prob, mtu); else local_prob = q->vars.prob; - rnd = prandom_u32(); + prandom_bytes(&rnd, 8); if (rnd < local_prob) return true; @@ -317,9 +317,10 @@ static void calculate_probability(struct Qdisc *sch) u32 qlen = sch->qstats.backlog; /* queue size in bytes */ psched_time_t qdelay = 0; /* in pschedtime */ psched_time_t qdelay_old = q->vars.qdelay; /* in pschedtime */ - s32 delta = 0; /* determines the change in probability */ - u32 oldprob; - u32 alpha, beta; + s64 delta = 0; /* determines the change in probability */ + u64 oldprob; + u64 alpha, beta; + u32 power; bool update_prob = true; q->vars.qdelay_old = q->vars.qdelay; @@ -339,38 +340,36 @@ static void calculate_probability(struct Qdisc *sch) * value for alpha as 0.125. In this implementation, we use values 0-32 * passed from user space to represent this. Also, alpha and beta have * unit of HZ and need to be scaled before they can used to update - * probability. alpha/beta are updated locally below by 1) scaling them - * appropriately 2) scaling down by 16 to come to 0-2 range. - * Please see paper for details. - * - * We scale alpha and beta differently depending on whether we are in - * light, medium or high dropping mode. + * probability. alpha/beta are updated locally below by scaling down + * by 16 to come to 0-2 range. */ - if (q->vars.prob < MAX_PROB / 100) { - alpha = - (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7; - beta = - (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7; - } else if (q->vars.prob < MAX_PROB / 10) { - alpha = - (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 5; - beta = - (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 5; - } else { - alpha = - (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; - beta = - (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; + alpha = ((u64)q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; + beta = ((u64)q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; + + /* We scale alpha and beta differently depending on how heavy the + * congestion is. Please see RFC 8033 for details. + */ + if (q->vars.prob < MAX_PROB / 10) { + alpha >>= 1; + beta >>= 1; + + power = 100; + while (q->vars.prob < div_u64(MAX_PROB, power) && + power <= 1000000) { + alpha >>= 2; + beta >>= 2; + power *= 10; + } } /* alpha and beta should be between 0 and 32, in multiples of 1/16 */ - delta += alpha * ((qdelay - q->params.target)); - delta += beta * ((qdelay - qdelay_old)); + delta += alpha * (u64)(qdelay - q->params.target); + delta += beta * (u64)(qdelay - qdelay_old); oldprob = q->vars.prob; /* to ensure we increase probability in steps of no more than 2% */ - if (delta > (s32)(MAX_PROB / (100 / 2)) && + if (delta > (s64)(MAX_PROB / (100 / 2)) && q->vars.prob >= MAX_PROB / 10) delta = (MAX_PROB / 100) * 2; |