diff options
Diffstat (limited to 'target/linux/generic/backport-4.19/392-v5.1-sch_cake-Make-the-dual-modes-fairer.patch')
| -rw-r--r-- | target/linux/generic/backport-4.19/392-v5.1-sch_cake-Make-the-dual-modes-fairer.patch | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/target/linux/generic/backport-4.19/392-v5.1-sch_cake-Make-the-dual-modes-fairer.patch b/target/linux/generic/backport-4.19/392-v5.1-sch_cake-Make-the-dual-modes-fairer.patch new file mode 100644 index 0000000000..cd94600152 --- /dev/null +++ b/target/linux/generic/backport-4.19/392-v5.1-sch_cake-Make-the-dual-modes-fairer.patch @@ -0,0 +1,217 @@ +From 712639929912c5eefb09facccb48d55b3f72c9f8 Mon Sep 17 00:00:00 2001 +From: George Amanakis <gamanakis@gmail.com> +Date: Fri, 1 Mar 2019 16:04:05 +0100 +Subject: [PATCH] sch_cake: Make the dual modes fairer +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +CAKE host fairness does not work well with TCP flows in dual-srchost and +dual-dsthost setup. The reason is that ACKs generated by TCP flows are +classified as sparse flows, and affect flow isolation from other hosts. Fix +this by calculating host_load based only on the bulk flows a host +generates. In a hash collision the host_bulk_flow_count values must be +decremented on the old hosts and incremented on the new ones *if* the queue +is in the bulk set. + +Reported-by: Pete Heist <peteheist@gmail.com> +Signed-off-by: George Amanakis <gamanakis@gmail.com> +Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk> +--- + net/sched/sch_cake.c | 92 ++++++++++++++++++++++++++++++-------------- + 1 file changed, 63 insertions(+), 29 deletions(-) + +--- a/net/sched/sch_cake.c ++++ b/net/sched/sch_cake.c +@@ -138,8 +138,8 @@ struct cake_flow { + struct cake_host { + u32 srchost_tag; + u32 dsthost_tag; +- u16 srchost_refcnt; +- u16 dsthost_refcnt; ++ u16 srchost_bulk_flow_count; ++ u16 dsthost_bulk_flow_count; + }; + + struct cake_heap_entry { +@@ -746,8 +746,10 @@ skip_hash: + * queue, accept the collision, update the host tags. + */ + q->way_collisions++; +- q->hosts[q->flows[reduced_hash].srchost].srchost_refcnt--; +- q->hosts[q->flows[reduced_hash].dsthost].dsthost_refcnt--; ++ if (q->flows[outer_hash + k].set == CAKE_SET_BULK) { ++ q->hosts[q->flows[reduced_hash].srchost].srchost_bulk_flow_count--; ++ q->hosts[q->flows[reduced_hash].dsthost].dsthost_bulk_flow_count--; ++ } + allocate_src = cake_dsrc(flow_mode); + allocate_dst = cake_ddst(flow_mode); + found: +@@ -767,13 +769,14 @@ found: + } + for (i = 0; i < CAKE_SET_WAYS; + i++, k = (k + 1) % CAKE_SET_WAYS) { +- if (!q->hosts[outer_hash + k].srchost_refcnt) ++ if (!q->hosts[outer_hash + k].srchost_bulk_flow_count) + break; + } + q->hosts[outer_hash + k].srchost_tag = srchost_hash; + found_src: + srchost_idx = outer_hash + k; +- q->hosts[srchost_idx].srchost_refcnt++; ++ if (q->flows[reduced_hash].set == CAKE_SET_BULK) ++ q->hosts[srchost_idx].srchost_bulk_flow_count++; + q->flows[reduced_hash].srchost = srchost_idx; + } + +@@ -789,13 +792,14 @@ found_src: + } + for (i = 0; i < CAKE_SET_WAYS; + i++, k = (k + 1) % CAKE_SET_WAYS) { +- if (!q->hosts[outer_hash + k].dsthost_refcnt) ++ if (!q->hosts[outer_hash + k].dsthost_bulk_flow_count) + break; + } + q->hosts[outer_hash + k].dsthost_tag = dsthost_hash; + found_dst: + dsthost_idx = outer_hash + k; +- q->hosts[dsthost_idx].dsthost_refcnt++; ++ if (q->flows[reduced_hash].set == CAKE_SET_BULK) ++ q->hosts[dsthost_idx].dsthost_bulk_flow_count++; + q->flows[reduced_hash].dsthost = dsthost_idx; + } + } +@@ -1793,20 +1797,30 @@ static s32 cake_enqueue(struct sk_buff * + b->sparse_flow_count++; + + if (cake_dsrc(q->flow_mode)) +- host_load = max(host_load, srchost->srchost_refcnt); ++ host_load = max(host_load, srchost->srchost_bulk_flow_count); + + if (cake_ddst(q->flow_mode)) +- host_load = max(host_load, dsthost->dsthost_refcnt); ++ host_load = max(host_load, dsthost->dsthost_bulk_flow_count); + + flow->deficit = (b->flow_quantum * + quantum_div[host_load]) >> 16; + } else if (flow->set == CAKE_SET_SPARSE_WAIT) { ++ struct cake_host *srchost = &b->hosts[flow->srchost]; ++ struct cake_host *dsthost = &b->hosts[flow->dsthost]; ++ + /* this flow was empty, accounted as a sparse flow, but actually + * in the bulk rotation. + */ + flow->set = CAKE_SET_BULK; + b->sparse_flow_count--; + b->bulk_flow_count++; ++ ++ if (cake_dsrc(q->flow_mode)) ++ srchost->srchost_bulk_flow_count++; ++ ++ if (cake_ddst(q->flow_mode)) ++ dsthost->dsthost_bulk_flow_count++; ++ + } + + if (q->buffer_used > q->buffer_max_used) +@@ -1974,23 +1988,8 @@ retry: + dsthost = &b->hosts[flow->dsthost]; + host_load = 1; + +- if (cake_dsrc(q->flow_mode)) +- host_load = max(host_load, srchost->srchost_refcnt); +- +- if (cake_ddst(q->flow_mode)) +- host_load = max(host_load, dsthost->dsthost_refcnt); +- +- WARN_ON(host_load > CAKE_QUEUES); +- + /* flow isolation (DRR++) */ + if (flow->deficit <= 0) { +- /* The shifted prandom_u32() is a way to apply dithering to +- * avoid accumulating roundoff errors +- */ +- flow->deficit += (b->flow_quantum * quantum_div[host_load] + +- (prandom_u32() >> 16)) >> 16; +- list_move_tail(&flow->flowchain, &b->old_flows); +- + /* Keep all flows with deficits out of the sparse and decaying + * rotations. No non-empty flow can go into the decaying + * rotation, so they can't get deficits +@@ -1999,6 +1998,13 @@ retry: + if (flow->head) { + b->sparse_flow_count--; + b->bulk_flow_count++; ++ ++ if (cake_dsrc(q->flow_mode)) ++ srchost->srchost_bulk_flow_count++; ++ ++ if (cake_ddst(q->flow_mode)) ++ dsthost->dsthost_bulk_flow_count++; ++ + flow->set = CAKE_SET_BULK; + } else { + /* we've moved it to the bulk rotation for +@@ -2008,6 +2014,22 @@ retry: + flow->set = CAKE_SET_SPARSE_WAIT; + } + } ++ ++ if (cake_dsrc(q->flow_mode)) ++ host_load = max(host_load, srchost->srchost_bulk_flow_count); ++ ++ if (cake_ddst(q->flow_mode)) ++ host_load = max(host_load, dsthost->dsthost_bulk_flow_count); ++ ++ WARN_ON(host_load > CAKE_QUEUES); ++ ++ /* The shifted prandom_u32() is a way to apply dithering to ++ * avoid accumulating roundoff errors ++ */ ++ flow->deficit += (b->flow_quantum * quantum_div[host_load] + ++ (prandom_u32() >> 16)) >> 16; ++ list_move_tail(&flow->flowchain, &b->old_flows); ++ + goto retry; + } + +@@ -2028,6 +2050,13 @@ retry: + &b->decaying_flows); + if (flow->set == CAKE_SET_BULK) { + b->bulk_flow_count--; ++ ++ if (cake_dsrc(q->flow_mode)) ++ srchost->srchost_bulk_flow_count--; ++ ++ if (cake_ddst(q->flow_mode)) ++ dsthost->dsthost_bulk_flow_count--; ++ + b->decaying_flow_count++; + } else if (flow->set == CAKE_SET_SPARSE || + flow->set == CAKE_SET_SPARSE_WAIT) { +@@ -2041,14 +2070,19 @@ retry: + if (flow->set == CAKE_SET_SPARSE || + flow->set == CAKE_SET_SPARSE_WAIT) + b->sparse_flow_count--; +- else if (flow->set == CAKE_SET_BULK) ++ else if (flow->set == CAKE_SET_BULK) { + b->bulk_flow_count--; +- else ++ ++ if (cake_dsrc(q->flow_mode)) ++ srchost->srchost_bulk_flow_count--; ++ ++ if (cake_ddst(q->flow_mode)) ++ dsthost->dsthost_bulk_flow_count--; ++ ++ } else + b->decaying_flow_count--; + + flow->set = CAKE_SET_NONE; +- srchost->srchost_refcnt--; +- dsthost->dsthost_refcnt--; + } + goto begin; + } |