/*
 * Copyright (c) 2016 Qualcomm Atheros, Inc
 *
 * GPL v2
 *
 * Based on net/sched/sch_fq_codel.c
 */
#ifndef __NET_SCHED_FQ_IMPL_H
#define __NET_SCHED_FQ_IMPL_H

#include <net/fq.h>

/* functions that are embedded into includer */

static struct sk_buff *fq_flow_dequeue(struct fq *fq,
				       struct fq_flow *flow)
{
	struct fq_tin *tin = flow->tin;
	struct fq_flow *i;
	struct sk_buff *skb;

	lockdep_assert_held(&fq->lock);

	skb = __skb_dequeue(&flow->queue);
	if (!skb)
		return NULL;

	tin->backlog_bytes -= skb->len;
	tin->backlog_packets--;
	flow->backlog -= skb->len;
	fq->backlog--;
	fq->memory_usage -= skb->truesize;

	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);
	}

	return skb;
}

static struct sk_buff *fq_tin_dequeue(struct fq *fq,
				      struct fq_tin *tin,
				      fq_tin_dequeue_t dequeue_func)
{
	struct fq_flow *flow;
	struct list_head *head;
	struct sk_buff *skb;

	lockdep_assert_held(&fq->lock);

begin:
	head = &tin->new_flows;
	if (list_empty(head)) {
		head = &tin->old_flows;
		if (list_empty(head))
			return NULL;
	}

	flow = list_first_entry(head, struct fq_flow, flowchain);

	if (flow->deficit <= 0) {
		flow->deficit += fq->quantum;
		list_move_tail(&flow->flowchain,
			       &tin->old_flows);
		goto begin;
	}

	skb = dequeue_func(fq, tin, flow);
	if (!skb) {
		/* force a pass through old_flows to prevent starvation */
		if ((head == &tin->new_flows) &&
		    !list_empty(&tin->old_flows)) {
			list_move_tail(&flow->flowchain, &tin->old_flows);
		} else {
			list_del_init(&flow->flowchain);
			flow->tin = NULL;
		}
		goto begin;
	}

	flow->deficit -= skb->len;
	tin->tx_bytes += skb->len;
	tin->tx_packets++;

	return skb;
}

static struct fq_flow *fq_flow_classify(struct fq *fq,
					struct fq_tin *tin,
					struct sk_buff *skb,
					fq_flow_get_default_t get_default_func)
{
	struct fq_flow *flow;
	u32 hash;
	u32 idx;

	lockdep_assert_held(&fq->lock);

	hash = skb_get_hash_perturb(skb, fq->perturbation);
	idx = reciprocal_scale(hash, fq->flows_cnt);
	flow = &fq->flows[idx];

	if (flow->tin && flow->tin != tin) {
		flow = get_default_func(fq, tin, idx, skb);
		tin->collisions++;
		fq->collisions++;
	}

	if (!flow->tin)
		tin->flows++;

	return flow;
}

static void fq_recalc_backlog(struct fq *fq,
			      struct fq_tin *tin,
			      struct fq_flow *flow)
{
	struct fq_flow *i;

	if (list_empty(&flow->backlogchain))
		list_add_tail(&flow->backlogchain, &fq->backlogs);

	i = flow;
	list_for_each_entry_continue_reverse(i, &fq->backlogs,
					     backlogchain)
		if (i->backlog > flow->backlog)
			break;

	list_move(&flow->backlogchain, &i->backlogchain);
}

static void fq_tin_enqueue(struct fq *fq,
			   struct fq_tin *tin,
			   struct sk_buff *skb,
			   fq_skb_free_t free_func,
			   fq_flow_get_default_t get_default_func)
{
	struct fq_flow *flow;

	lockdep_assert_held(&fq->lock);

	flow = fq_flow_classify(fq, tin, skb, get_default_func);

	flow->tin = tin;
	flow->backlog += skb->len;
	tin->backlog_bytes += skb->len;
	tin->backlog_packets++;
	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,
			      &tin->new_flows);
	}

	__skb_queue_tail(&flow->queue, skb);

	if (fq->backlog > fq->limit || fq->memory_usage > fq->memory_limit) {
		flow = list_first_entry_or_null(&fq->backlogs,
						struct fq_flow,
						backlogchain);
		if (!flow)
			return;

		skb = fq_flow_dequeue(fq, flow);
		if (!skb)
			return;

		free_func(fq, flow->tin, flow, skb);

		flow->tin->overlimit++;
		fq->overlimit++;
		if (fq->memory_usage > fq->memory_limit)
			fq->overmemory++;
	}
}

static void fq_flow_reset(struct fq *fq,
			  struct fq_flow *flow,
			  fq_skb_free_t free_func)
{
	struct sk_buff *skb;

	while ((skb = fq_flow_dequeue(fq, flow)))
		free_func(fq, flow->tin, flow, skb);

	if (!list_empty(&flow->flowchain))
		list_del_init(&flow->flowchain);

	if (!list_empty(&flow->backlogchain))
		list_del_init(&flow->backlogchain);

	flow->tin = NULL;

	WARN_ON_ONCE(flow->backlog);
}

static void fq_tin_reset(struct fq *fq,
			 struct fq_tin *tin,
			 fq_skb_free_t free_func)
{
	struct list_head *head;
	struct fq_flow *flow;

	for (;;) {
		head = &tin->new_flows;
		if (list_empty(head)) {
			head = &tin->old_flows;
			if (list_empty(head))
				break;
		}

		flow = list_first_entry(head, struct fq_flow, flowchain);
		fq_flow_reset(fq, flow, free_func);
	}

	WARN_ON_ONCE(tin->backlog_bytes);
	WARN_ON_ONCE(tin->backlog_packets);
}

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);
}

static void fq_tin_init(struct fq_tin *tin)
{
	INIT_LIST_HEAD(&tin->new_flows);
	INIT_LIST_HEAD(&tin->old_flows);
}

static int fq_init(struct fq *fq, int flows_cnt)
{
	int i;

	memset(fq, 0, sizeof(fq[0]));
	INIT_LIST_HEAD(&fq->backlogs);
	spin_lock_init(&fq->lock);
	fq->flows_cnt = max_t(u32, flows_cnt, 1);
	fq->perturbation = prandom_u32();
	fq->quantum = 300;
	fq->limit = 8192;
	fq->memory_limit = 16 << 20; /* 16 MBytes */

	fq->flows = kcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
	if (!fq->flows)
		return -ENOMEM;

	for (i = 0; i < fq->flows_cnt; i++)
		fq_flow_init(&fq->flows[i]);

	return 0;
}

static void fq_reset(struct fq *fq,
		     fq_skb_free_t free_func)
{
	int i;

	for (i = 0; i < fq->flows_cnt; i++)
		fq_flow_reset(fq, &fq->flows[i], free_func);

	kfree(fq->flows);
	fq->flows = NULL;
}

#endif
pi/hed.h?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>include/acpi/hed.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/acpi/hed.h?h=nds-private-remove&amp;id=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>0c744ea4f77d72b3dcebb7a8f2684633ec79be88</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/acpi/hed.h?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7&amp;id2=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>diff</a>)</td></tr></table>
<div class='commit-subject'>tracing: Fix hwlat kthread migration</div><div class='commit-msg'>The hwlat tracer creates a kernel thread at start of the tracer. It is
pinned to a single CPU and will move to the next CPU after each period of
running. If the user modifies the migration thread's affinity, it will not
change after that happens.

The original code created the thread at the first instance it was called,
but later was changed to destroy the thread after the tracer was finished,
and would not be created until the next instance of the tracer was
established. The code that initialized the affinity was only called on the
initial instantiation of the tracer. After that, it was not initialized, and
the previous affinity did not match the current newly created one, making
it appear that the user modified the thread's affinity when it did not, and
the thread failed to migrate again.

Cc: stable@vger.kernel.org
Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>Diffstat</a> (limited to 'include/acpi/hed.h')</div><table summary='diffstat' class='diffstat'>