--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Wed, 25 Nov 2020 18:03:46 +0100
+Subject: [PATCH] net/fq_impl: bulk-free packets from a flow on overmemory
+
+This is similar to what sch_fq_codel does. It also amortizes the worst
+case cost of a follow-up patch that changes the selection of the biggest
+flow for dropping packets
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/fq_impl.h
++++ b/include/net/fq_impl.h
+@@ -11,17 +11,25 @@
+
+ /* functions that are embedded into includer */
+
++
++static void
++__fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
++ unsigned int bytes, unsigned int truesize)
++{
++ struct fq_tin *tin = flow->tin;
++
++ tin->backlog_bytes -= bytes;
++ tin->backlog_packets -= packets;
++ flow->backlog -= bytes;
++ fq->backlog -= packets;
++ fq->memory_usage -= truesize;
++}
++
+ static void fq_adjust_removal(struct fq *fq,
+ struct fq_flow *flow,
+ struct sk_buff *skb)
+ {
+- struct fq_tin *tin = flow->tin;
+-
+- tin->backlog_bytes -= skb->len;
+- tin->backlog_packets--;
+- flow->backlog -= skb->len;
+- fq->backlog--;
+- fq->memory_usage -= skb->truesize;
++ __fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
+ }
+
+ static void fq_rejigger_backlog(struct fq *fq, struct fq_flow *flow)
+@@ -59,6 +67,34 @@ static struct sk_buff *fq_flow_dequeue(s
+ return skb;
+ }
+
++static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
++ fq_skb_free_t free_func)
++{
++ unsigned int packets = 0, bytes = 0, truesize = 0;
++ struct fq_tin *tin = flow->tin;
++ struct sk_buff *skb;
++ int pending;
++
++ lockdep_assert_held(&fq->lock);
++
++ pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
++ do {
++ skb = __skb_dequeue(&flow->queue);
++ if (!skb)
++ break;
++
++ packets++;
++ bytes += skb->len;
++ truesize += skb->truesize;
++ free_func(fq, tin, flow, skb);
++ } while (packets < pending);
++
++ __fq_adjust_removal(fq, flow, packets, bytes, truesize);
++ fq_rejigger_backlog(fq, flow);
++
++ return packets;
++}
++
+ static struct sk_buff *fq_tin_dequeue(struct fq *fq,
+ struct fq_tin *tin,
+ fq_tin_dequeue_t dequeue_func)
+@@ -190,12 +226,9 @@ static void fq_tin_enqueue(struct fq *fq
+ if (!flow)
+ return;
+
+- skb = fq_flow_dequeue(fq, flow);
+- if (!skb)
++ if (!fq_flow_drop(fq, flow, free_func))
+ return;
+
+- free_func(fq, flow->tin, flow, skb);
+-
+ flow->tin->overlimit++;
+ fq->overlimit++;
+ if (oom) {
--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Wed, 25 Nov 2020 18:09:10 +0100
+Subject: [PATCH] net/fq_impl: drop get_default_func, move default flow to
+ fq_tin
+
+Simplifies the code and prepares for a rework of scanning for flows on
+overmemory drop.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/fq.h
++++ b/include/net/fq.h
+@@ -47,6 +47,7 @@ struct fq_flow {
+ struct fq_tin {
+ struct list_head new_flows;
+ struct list_head old_flows;
++ struct fq_flow default_flow;
+ u32 backlog_bytes;
+ u32 backlog_packets;
+ u32 overlimit;
+--- a/include/net/fq_impl.h
++++ b/include/net/fq_impl.h
+@@ -151,8 +151,7 @@ static u32 fq_flow_idx(struct fq *fq, st
+
+ static struct fq_flow *fq_flow_classify(struct fq *fq,
+ struct fq_tin *tin, u32 idx,
+- struct sk_buff *skb,
+- fq_flow_get_default_t get_default_func)
++ struct sk_buff *skb)
+ {
+ struct fq_flow *flow;
+
+@@ -160,7 +159,7 @@ static struct fq_flow *fq_flow_classify(
+
+ flow = &fq->flows[idx];
+ if (flow->tin && flow->tin != tin) {
+- flow = get_default_func(fq, tin, idx, skb);
++ flow = &tin->default_flow;
+ tin->collisions++;
+ fq->collisions++;
+ }
+@@ -192,15 +191,14 @@ static void fq_recalc_backlog(struct fq
+ static void fq_tin_enqueue(struct fq *fq,
+ struct fq_tin *tin, u32 idx,
+ struct sk_buff *skb,
+- fq_skb_free_t free_func,
+- fq_flow_get_default_t get_default_func)
++ fq_skb_free_t free_func)
+ {
+ struct fq_flow *flow;
+ bool oom;
+
+ lockdep_assert_held(&fq->lock);
+
+- flow = fq_flow_classify(fq, tin, idx, skb, get_default_func);
++ flow = fq_flow_classify(fq, tin, idx, skb);
+
+ flow->tin = tin;
+ flow->backlog += skb->len;
+@@ -331,6 +329,7 @@ static void fq_tin_init(struct fq_tin *t
+ {
+ INIT_LIST_HEAD(&tin->new_flows);
+ INIT_LIST_HEAD(&tin->old_flows);
++ fq_flow_init(&tin->default_flow);
+ }
+
+ static int fq_init(struct fq *fq, int flows_cnt)
+--- a/net/mac80211/ieee80211_i.h
++++ b/net/mac80211/ieee80211_i.h
+@@ -855,7 +855,6 @@ enum txq_info_flags {
+ */
+ struct txq_info {
+ struct fq_tin tin;
+- struct fq_flow def_flow;
+ struct codel_vars def_cvars;
+ struct codel_stats cstats;
+ struct sk_buff_head frags;
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -1322,7 +1322,7 @@ static struct sk_buff *codel_dequeue_fun
+ fq = &local->fq;
+
+ if (cvars == &txqi->def_cvars)
+- flow = &txqi->def_flow;
++ flow = &txqi->tin.default_flow;
+ else
+ flow = &fq->flows[cvars - local->cvars];
+
+@@ -1365,7 +1365,7 @@ static struct sk_buff *fq_tin_dequeue_fu
+ cparams = &local->cparams;
+ }
+
+- if (flow == &txqi->def_flow)
++ if (flow == &tin->default_flow)
+ cvars = &txqi->def_cvars;
+ else
+ cvars = &local->cvars[flow - fq->flows];
+@@ -1392,17 +1392,6 @@ static void fq_skb_free_func(struct fq *
+ ieee80211_free_txskb(&local->hw, skb);
+ }
+
+-static struct fq_flow *fq_flow_get_default_func(struct fq *fq,
+- struct fq_tin *tin,
+- int idx,
+- struct sk_buff *skb)
+-{
+- struct txq_info *txqi;
+-
+- txqi = container_of(tin, struct txq_info, tin);
+- return &txqi->def_flow;
+-}
+-
+ static void ieee80211_txq_enqueue(struct ieee80211_local *local,
+ struct txq_info *txqi,
+ struct sk_buff *skb)
+@@ -1415,8 +1404,7 @@ static void ieee80211_txq_enqueue(struct
+
+ spin_lock_bh(&fq->lock);
+ fq_tin_enqueue(fq, tin, flow_idx, skb,
+- fq_skb_free_func,
+- fq_flow_get_default_func);
++ fq_skb_free_func);
+ spin_unlock_bh(&fq->lock);
+ }
+
+@@ -1459,7 +1447,6 @@ void ieee80211_txq_init(struct ieee80211
+ struct txq_info *txqi, int tid)
+ {
+ fq_tin_init(&txqi->tin);
+- fq_flow_init(&txqi->def_flow);
+ codel_vars_init(&txqi->def_cvars);
+ codel_stats_init(&txqi->cstats);
+ __skb_queue_head_init(&txqi->frags);
+@@ -3310,8 +3297,7 @@ static bool ieee80211_amsdu_aggregate(st
+ */
+
+ tin = &txqi->tin;
+- flow = fq_flow_classify(fq, tin, flow_idx, skb,
+- fq_flow_get_default_func);
++ flow = fq_flow_classify(fq, tin, flow_idx, skb);
+ head = skb_peek_tail(&flow->queue);
+ if (!head || skb_is_gso(head))
+ goto out;
--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Wed, 25 Nov 2020 18:10:34 +0100
+Subject: [PATCH] net/fq_impl: do not maintain a backlog-sorted list of
+ flows
+
+A sorted flow list is only needed to drop packets in the biggest flow when
+hitting the overmemory condition.
+By scanning flows only when needed, we can avoid paying the cost of
+maintaining the list under normal conditions
+In order to avoid scanning lots of empty flows and touching too many cold
+cache lines, a bitmap of flows with backlog is maintained
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/fq.h
++++ b/include/net/fq.h
+@@ -19,8 +19,6 @@ struct fq_tin;
+ * @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
+ * (deficit round robin) based round robin queuing similar to the one
+ * found in net/sched/sch_fq_codel.c
+- * @backlogchain: can be linked to other fq_flow and fq. Used to keep track of
+- * fat flows and efficient head-dropping if packet limit is reached
+ * @queue: sk_buff queue to hold packets
+ * @backlog: number of bytes pending in the queue. The number of packets can be
+ * found in @queue.qlen
+@@ -29,7 +27,6 @@ struct fq_tin;
+ struct fq_flow {
+ struct fq_tin *tin;
+ struct list_head flowchain;
+- struct list_head backlogchain;
+ struct sk_buff_head queue;
+ u32 backlog;
+ int deficit;
+@@ -47,6 +44,7 @@ struct fq_flow {
+ struct fq_tin {
+ struct list_head new_flows;
+ struct list_head old_flows;
++ struct list_head tin_list;
+ struct fq_flow default_flow;
+ u32 backlog_bytes;
+ u32 backlog_packets;
+@@ -60,14 +58,14 @@ struct fq_tin {
+ /**
+ * struct fq - main container for fair queuing purposes
+ *
+- * @backlogs: linked to fq_flows. Used to maintain fat flows for efficient
+- * head-dropping when @backlog reaches @limit
+ * @limit: max number of packets that can be queued across all flows
+ * @backlog: number of packets queued across all flows
+ */
+ struct fq {
+ struct fq_flow *flows;
+- struct list_head backlogs;
++ unsigned long *flows_bitmap;
++
++ struct list_head tin_backlog;
+ spinlock_t lock;
+ u32 flows_cnt;
+ u32 limit;
+--- a/include/net/fq_impl.h
++++ b/include/net/fq_impl.h
+@@ -17,12 +17,24 @@ __fq_adjust_removal(struct fq *fq, struc
+ unsigned int bytes, unsigned int truesize)
+ {
+ struct fq_tin *tin = flow->tin;
++ int idx;
+
+ tin->backlog_bytes -= bytes;
+ tin->backlog_packets -= packets;
+ flow->backlog -= bytes;
+ fq->backlog -= packets;
+ fq->memory_usage -= truesize;
++
++ if (flow->backlog)
++ return;
++
++ if (flow == &tin->default_flow) {
++ list_del_init(&tin->tin_list);
++ return;
++ }
++
++ idx = flow - fq->flows;
++ __clear_bit(idx, fq->flows_bitmap);
+ }
+
+ static void fq_adjust_removal(struct fq *fq,
+@@ -32,24 +44,6 @@ static void fq_adjust_removal(struct fq
+ __fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
+ }
+
+-static void fq_rejigger_backlog(struct fq *fq, struct fq_flow *flow)
+-{
+- struct fq_flow *i;
+-
+- if (flow->backlog == 0) {
+- list_del_init(&flow->backlogchain);
+- } else {
+- i = flow;
+-
+- list_for_each_entry_continue(i, &fq->backlogs, backlogchain)
+- if (i->backlog < flow->backlog)
+- break;
+-
+- list_move_tail(&flow->backlogchain,
+- &i->backlogchain);
+- }
+-}
+-
+ static struct sk_buff *fq_flow_dequeue(struct fq *fq,
+ struct fq_flow *flow)
+ {
+@@ -62,7 +56,6 @@ static struct sk_buff *fq_flow_dequeue(s
+ return NULL;
+
+ fq_adjust_removal(fq, flow, skb);
+- fq_rejigger_backlog(fq, flow);
+
+ return skb;
+ }
+@@ -90,7 +83,6 @@ static int fq_flow_drop(struct fq *fq, s
+ } while (packets < pending);
+
+ __fq_adjust_removal(fq, flow, packets, bytes, truesize);
+- fq_rejigger_backlog(fq, flow);
+
+ return packets;
+ }
+@@ -170,22 +162,36 @@ static struct fq_flow *fq_flow_classify(
+ return flow;
+ }
+
+-static void fq_recalc_backlog(struct fq *fq,
+- struct fq_tin *tin,
+- struct fq_flow *flow)
++static struct fq_flow *fq_find_fattest_flow(struct fq *fq)
+ {
+- struct fq_flow *i;
++ struct fq_tin *tin;
++ struct fq_flow *flow = NULL;
++ u32 len = 0;
++ int i;
+
+- if (list_empty(&flow->backlogchain))
+- list_add_tail(&flow->backlogchain, &fq->backlogs);
++ for_each_set_bit(i, fq->flows_bitmap, fq->flows_cnt) {
++ struct fq_flow *cur = &fq->flows[i];
++ unsigned int cur_len;
+
+- i = flow;
+- list_for_each_entry_continue_reverse(i, &fq->backlogs,
+- backlogchain)
+- if (i->backlog > flow->backlog)
+- break;
++ cur_len = cur->backlog;
++ if (cur_len <= len)
++ continue;
+
+- list_move(&flow->backlogchain, &i->backlogchain);
++ flow = cur;
++ len = cur_len;
++ }
++
++ list_for_each_entry(tin, &fq->tin_backlog, tin_list) {
++ unsigned int cur_len = tin->default_flow.backlog;
++
++ if (cur_len <= len)
++ continue;
++
++ flow = &tin->default_flow;
++ len = cur_len;
++ }
++
++ return flow;
+ }
+
+ static void fq_tin_enqueue(struct fq *fq,
+@@ -200,6 +206,13 @@ static void fq_tin_enqueue(struct fq *fq
+
+ flow = fq_flow_classify(fq, tin, idx, skb);
+
++ if (!flow->backlog) {
++ if (flow != &tin->default_flow)
++ __set_bit(idx, fq->flows_bitmap);
++ else if (list_empty(&tin->tin_list))
++ list_add(&tin->tin_list, &fq->tin_backlog);
++ }
++
+ flow->tin = tin;
+ flow->backlog += skb->len;
+ tin->backlog_bytes += skb->len;
+@@ -207,8 +220,6 @@ static void fq_tin_enqueue(struct fq *fq
+ fq->memory_usage += skb->truesize;
+ fq->backlog++;
+
+- fq_recalc_backlog(fq, tin, flow);
+-
+ if (list_empty(&flow->flowchain)) {
+ flow->deficit = fq->quantum;
+ list_add_tail(&flow->flowchain,
+@@ -218,9 +229,7 @@ static void fq_tin_enqueue(struct fq *fq
+ __skb_queue_tail(&flow->queue, skb);
+ oom = (fq->memory_usage > fq->memory_limit);
+ while (fq->backlog > fq->limit || oom) {
+- flow = list_first_entry_or_null(&fq->backlogs,
+- struct fq_flow,
+- backlogchain);
++ flow = fq_find_fattest_flow(fq);
+ if (!flow)
+ return;
+
+@@ -255,8 +264,6 @@ static void fq_flow_filter(struct fq *fq
+ fq_adjust_removal(fq, flow, skb);
+ free_func(fq, tin, flow, skb);
+ }
+-
+- fq_rejigger_backlog(fq, flow);
+ }
+
+ static void fq_tin_filter(struct fq *fq,
+@@ -279,16 +286,18 @@ static void fq_flow_reset(struct fq *fq,
+ struct fq_flow *flow,
+ fq_skb_free_t free_func)
+ {
++ struct fq_tin *tin = flow->tin;
+ struct sk_buff *skb;
+
+ while ((skb = fq_flow_dequeue(fq, flow)))
+- free_func(fq, flow->tin, flow, skb);
++ free_func(fq, tin, flow, skb);
+
+- if (!list_empty(&flow->flowchain))
++ if (!list_empty(&flow->flowchain)) {
+ list_del_init(&flow->flowchain);
+-
+- if (!list_empty(&flow->backlogchain))
+- list_del_init(&flow->backlogchain);
++ if (list_empty(&tin->new_flows) &&
++ list_empty(&tin->old_flows))
++ list_del_init(&tin->tin_list);
++ }
+
+ flow->tin = NULL;
+
+@@ -314,6 +323,7 @@ static void fq_tin_reset(struct fq *fq,
+ fq_flow_reset(fq, flow, free_func);
+ }
+
++ WARN_ON_ONCE(!list_empty(&tin->tin_list));
+ WARN_ON_ONCE(tin->backlog_bytes);
+ WARN_ON_ONCE(tin->backlog_packets);
+ }
+@@ -321,7 +331,6 @@ static void fq_tin_reset(struct fq *fq,
+ static void fq_flow_init(struct fq_flow *flow)
+ {
+ INIT_LIST_HEAD(&flow->flowchain);
+- INIT_LIST_HEAD(&flow->backlogchain);
+ __skb_queue_head_init(&flow->queue);
+ }
+
+@@ -329,6 +338,7 @@ static void fq_tin_init(struct fq_tin *t
+ {
+ INIT_LIST_HEAD(&tin->new_flows);
+ INIT_LIST_HEAD(&tin->old_flows);
++ INIT_LIST_HEAD(&tin->tin_list);
+ fq_flow_init(&tin->default_flow);
+ }
+
+@@ -337,8 +347,8 @@ static int fq_init(struct fq *fq, int fl
+ int i;
+
+ memset(fq, 0, sizeof(fq[0]));
+- INIT_LIST_HEAD(&fq->backlogs);
+ spin_lock_init(&fq->lock);
++ INIT_LIST_HEAD(&fq->tin_backlog);
+ fq->flows_cnt = max_t(u32, flows_cnt, 1);
+ fq->quantum = 300;
+ fq->limit = 8192;
+@@ -348,6 +358,14 @@ static int fq_init(struct fq *fq, int fl
+ if (!fq->flows)
+ return -ENOMEM;
+
++ fq->flows_bitmap = kcalloc(BITS_TO_LONGS(fq->flows_cnt), sizeof(long),
++ GFP_KERNEL);
++ if (!fq->flows_bitmap) {
++ kvfree(fq->flows);
++ fq->flows = NULL;
++ return -ENOMEM;
++ }
++
+ for (i = 0; i < fq->flows_cnt; i++)
+ fq_flow_init(&fq->flows[i]);
+
+@@ -364,6 +382,9 @@ static void fq_reset(struct fq *fq,
+
+ kvfree(fq->flows);
+ fq->flows = NULL;
++
++ kfree(fq->flows_bitmap);
++ fq->flows_bitmap = NULL;
+ }
+
+ #endif
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3364,8 +3364,6 @@ out_recalc:
+ if (head->len != orig_len) {
+ flow->backlog += head->len - orig_len;
+ tin->backlog_bytes += head->len - orig_len;
+-
+- fq_recalc_backlog(fq, tin, flow);
+ }
+ out:
+ spin_unlock_bh(&fq->lock);
projects / openwrt / staging / rmilecki.git / commitdiff