Commit 07be2fed authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
Browse files

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: default avatarFelix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201218184718.93650-1-nbd@nbd.name


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 9e8789c8

include/net/fq_impl.h

+44 −11
Original line number Diff line number Diff line
@@ -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(struct fq *fq, 
	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) {