Adding upstream version 2.9.5.upstream/2.9.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 761 insertions, 0 deletions

diff --git a/src/queue.c b/src/queue.c
new file mode 100644
index 0000000..f20285b
--- /dev/null
+++ b/src/queue.c
@@ -0,0 +1,761 @@
+/*
+ * Queue management functions.
+ *
+ * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+/* Short explanation on the locking, which is far from being trivial : a
+ * pendconn is a list element which necessarily is associated with an existing
+ * stream. It has pendconn->strm always valid. A pendconn may only be in one of
+ * these three states :
+ *   - unlinked : in this case it is an empty list head ;
+ *   - linked into the server's queue ;
+ *   - linked into the proxy's queue.
+ *
+ * A stream does not necessarily have such a pendconn. Thus the pendconn is
+ * designated by the stream->pend_pos pointer. This results in some properties :
+ *   - pendconn->strm->pend_pos is never NULL for any valid pendconn
+ *   - if p->node.node.leaf_p is NULL, the element is unlinked,
+ *     otherwise it necessarily belongs to one of the other lists ; this may
+ *     not be atomically checked under threads though ;
+ *   - pendconn->px is never NULL if pendconn->list is not empty
+ *   - pendconn->srv is never NULL if pendconn->list is in the server's queue,
+ *     and is always NULL if pendconn->list is in the backend's queue or empty.
+ *   - pendconn->target is NULL while the element is queued, and points to the
+ *     assigned server when the pendconn is picked.
+ *
+ * Threads complicate the design a little bit but rules remain simple :
+ *   - the server's queue lock must be held at least when manipulating the
+ *     server's queue, which is when adding a pendconn to the queue and when
+ *     removing a pendconn from the queue. It protects the queue's integrity.
+ *
+ *   - the proxy's queue lock must be held at least when manipulating the
+ *     proxy's queue, which is when adding a pendconn to the queue and when
+ *     removing a pendconn from the queue. It protects the queue's integrity.
+ *
+ *   - both locks are compatible and may be held at the same time.
+ *
+ *   - a pendconn_add() is only performed by the stream which will own the
+ *     pendconn ; the pendconn is allocated at this moment and returned ; it is
+ *     added to either the server or the proxy's queue while holding this
+s *     queue's lock.
+ *
+ *   - the pendconn is then met by a thread walking over the proxy or server's
+ *     queue with the respective lock held. This lock is exclusive and the
+ *     pendconn can only appear in one queue so by definition a single thread
+ *     may find this pendconn at a time.
+ *
+ *   - the pendconn is unlinked either by its own stream upon success/abort/
+ *     free, or by another one offering it its server slot. This is achieved by
+ *     pendconn_process_next_strm() under either the server or proxy's lock,
+ *     pendconn_redistribute() under the server's lock, pendconn_grab_from_px()
+ *     under the proxy's lock, or pendconn_unlink() under either the proxy's or
+ *     the server's lock depending on the queue the pendconn is attached to.
+ *
+ *   - no single operation except the pendconn initialisation prior to the
+ *     insertion are performed without eithre a queue lock held or the element
+ *     being unlinked and visible exclusively to its stream.
+ *
+ *   - pendconn_grab_from_px() and pendconn_process_next_strm() assign ->target
+ *     so that the stream knows what server to work with (via
+ *     pendconn_dequeue() which sets it on strm->target).
+ *
+ *   - a pendconn doesn't switch between queues, it stays where it is.
+ */
+
+#include <import/eb32tree.h>
+#include <haproxy/api.h>
+#include <haproxy/backend.h>
+#include <haproxy/http_rules.h>
+#include <haproxy/pool.h>
+#include <haproxy/queue.h>
+#include <haproxy/sample.h>
+#include <haproxy/server-t.h>
+#include <haproxy/stream.h>
+#include <haproxy/task.h>
+#include <haproxy/tcp_rules.h>
+#include <haproxy/thread.h>
+#include <haproxy/time.h>
+#include <haproxy/tools.h>
+
+
+#define NOW_OFFSET_BOUNDARY()          ((now_ms - (TIMER_LOOK_BACK >> 12)) & 0xfffff)
+#define KEY_CLASS(key)                 ((u32)key & 0xfff00000)
+#define KEY_OFFSET(key)                ((u32)key & 0x000fffff)
+#define KEY_CLASS_OFFSET_BOUNDARY(key) (KEY_CLASS(key) | NOW_OFFSET_BOUNDARY())
+#define MAKE_KEY(class, offset)        (((u32)(class + 0x7ff) << 20) | ((u32)(now_ms + offset) & 0xfffff))
+
+DECLARE_POOL(pool_head_pendconn, "pendconn", sizeof(struct pendconn));
+
+/* returns the effective dynamic maxconn for a server, considering the minconn
+ * and the proxy's usage relative to its dynamic connections limit. It is
+ * expected that 0 < s->minconn <= s->maxconn when this is called. If the
+ * server is currently warming up, the slowstart is also applied to the
+ * resulting value, which can be lower than minconn in this case, but never
+ * less than 1.
+ */
+unsigned int srv_dynamic_maxconn(const struct server *s)
+{
+	unsigned int max;
+
+	if (s->proxy->beconn >= s->proxy->fullconn)
+		/* no fullconn or proxy is full */
+		max = s->maxconn;
+	else if (s->minconn == s->maxconn)
+		/* static limit */
+		max = s->maxconn;
+	else max = MAX(s->minconn,
+		       s->proxy->beconn * s->maxconn / s->proxy->fullconn);
+
+	if ((s->cur_state == SRV_ST_STARTING) &&
+	    ns_to_sec(now_ns) < s->last_change + s->slowstart &&
+	    ns_to_sec(now_ns) >= s->last_change) {
+		unsigned int ratio;
+		ratio = 100 * (ns_to_sec(now_ns) - s->last_change) / s->slowstart;
+		max = MAX(1, max * ratio / 100);
+	}
+	return max;
+}
+
+/* Remove the pendconn from the server's queue. At this stage, the connection
+ * is not really dequeued. It will be done during the process_stream. It is
+ * up to the caller to atomically decrement the pending counts.
+ *
+ * The caller must own the lock on the server queue. The pendconn must still be
+ * queued (p->node.leaf_p != NULL) and must be in a server (p->srv != NULL).
+ */
+static void __pendconn_unlink_srv(struct pendconn *p)
+{
+	p->strm->logs.srv_queue_pos += _HA_ATOMIC_LOAD(&p->queue->idx) - p->queue_idx;
+	eb32_delete(&p->node);
+}
+
+/* Remove the pendconn from the proxy's queue. At this stage, the connection
+ * is not really dequeued. It will be done during the process_stream. It is
+ * up to the caller to atomically decrement the pending counts.
+ *
+ * The caller must own the lock on the proxy queue. The pendconn must still be
+ * queued (p->node.leaf_p != NULL) and must be in the proxy (p->srv == NULL).
+ */
+static void __pendconn_unlink_prx(struct pendconn *p)
+{
+	p->strm->logs.prx_queue_pos += _HA_ATOMIC_LOAD(&p->queue->idx) - p->queue_idx;
+	eb32_delete(&p->node);
+}
+
+/* Locks the queue the pendconn element belongs to. This relies on both p->px
+ * and p->srv to be properly initialized (which is always the case once the
+ * element has been added).
+ */
+static inline void pendconn_queue_lock(struct pendconn *p)
+{
+	HA_SPIN_LOCK(QUEUE_LOCK, &p->queue->lock);
+}
+
+/* Unlocks the queue the pendconn element belongs to. This relies on both p->px
+ * and p->srv to be properly initialized (which is always the case once the
+ * element has been added).
+ */
+static inline void pendconn_queue_unlock(struct pendconn *p)
+{
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &p->queue->lock);
+}
+
+/* Removes the pendconn from the server/proxy queue. At this stage, the
+ * connection is not really dequeued. It will be done during process_stream().
+ * This function takes all the required locks for the operation. The pendconn
+ * must be valid, though it doesn't matter if it was already unlinked. Prefer
+ * pendconn_cond_unlink() to first check <p>. It also forces a serialization
+ * on p->del_lock to make sure another thread currently waking it up finishes
+ * first.
+ */
+void pendconn_unlink(struct pendconn *p)
+{
+	struct queue  *q  = p->queue;
+	struct proxy  *px = q->px;
+	struct server *sv = q->sv;
+	uint oldidx;
+	int done = 0;
+
+	oldidx = _HA_ATOMIC_LOAD(&p->queue->idx);
+	HA_SPIN_LOCK(QUEUE_LOCK, &q->lock);
+	HA_SPIN_LOCK(QUEUE_LOCK, &p->del_lock);
+
+	if (p->node.node.leaf_p) {
+		eb32_delete(&p->node);
+		done = 1;
+	}
+
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &p->del_lock);
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &q->lock);
+
+	if (done) {
+		oldidx -= p->queue_idx;
+		if (sv)
+			p->strm->logs.srv_queue_pos += oldidx;
+		else
+			p->strm->logs.prx_queue_pos += oldidx;
+
+		_HA_ATOMIC_DEC(&q->length);
+		_HA_ATOMIC_DEC(&px->totpend);
+	}
+}
+
+/* Retrieve the first pendconn from tree <pendconns>. Classes are always
+ * considered first, then the time offset. The time does wrap, so the
+ * lookup is performed twice, one to retrieve the first class and a second
+ * time to retrieve the earliest time in this class.
+ */
+static struct pendconn *pendconn_first(struct eb_root *pendconns)
+{
+	struct eb32_node *node, *node2 = NULL;
+	u32 key;
+
+	node = eb32_first(pendconns);
+	if (!node)
+		return NULL;
+
+	key = KEY_CLASS_OFFSET_BOUNDARY(node->key);
+	node2 = eb32_lookup_ge(pendconns, key);
+
+	if (!node2 ||
+	    KEY_CLASS(node2->key) != KEY_CLASS(node->key)) {
+		/* no other key in the tree, or in this class */
+		return eb32_entry(node, struct pendconn, node);
+	}
+
+	/* found a better key */
+	return eb32_entry(node2, struct pendconn, node);
+}
+
+/* Process the next pending connection from either a server or a proxy, and
+ * returns a strictly positive value on success (see below). If no pending
+ * connection is found, 0 is returned.  Note that neither <srv> nor <px> may be
+ * NULL.  Priority is given to the oldest request in the queue if both <srv> and
+ * <px> have pending requests. This ensures that no request will be left
+ * unserved.  The <px> queue is not considered if the server (or a tracked
+ * server) is not RUNNING, is disabled, or has a null weight (server going
+ * down). The <srv> queue is still considered in this case, because if some
+ * connections remain there, it means that some requests have been forced there
+ * after it was seen down (eg: due to option persist).  The stream is
+ * immediately marked as "assigned", and both its <srv> and <srv_conn> are set
+ * to <srv>.
+ *
+ * The proxy's queue will be consulted only if px_ok is non-zero.
+ *
+ * This function must only be called if the server queue is locked _AND_ the
+ * proxy queue is not. Today it is only called by process_srv_queue.
+ * When a pending connection is dequeued, this function returns 1 if a pendconn
+ * is dequeued, otherwise 0.
+ */
+static int pendconn_process_next_strm(struct server *srv, struct proxy *px, int px_ok)
+{
+	struct pendconn *p = NULL;
+	struct pendconn *pp = NULL;
+	u32 pkey, ppkey;
+
+	p = NULL;
+	if (srv->queue.length)
+		p = pendconn_first(&srv->queue.head);
+
+	pp = NULL;
+	if (px_ok && px->queue.length) {
+		/* the lock only remains held as long as the pp is
+		 * in the proxy's queue.
+		 */
+		HA_SPIN_LOCK(QUEUE_LOCK,  &px->queue.lock);
+		pp = pendconn_first(&px->queue.head);
+		if (!pp)
+			HA_SPIN_UNLOCK(QUEUE_LOCK,  &px->queue.lock);
+	}
+
+	if (!p && !pp)
+		return 0;
+	else if (!pp)
+		goto use_p; /*  p != NULL */
+	else if (!p)
+		goto use_pp; /* pp != NULL */
+
+	/* p != NULL && pp != NULL*/
+
+	if (KEY_CLASS(p->node.key) < KEY_CLASS(pp->node.key))
+		goto use_p;
+
+	if (KEY_CLASS(pp->node.key) < KEY_CLASS(p->node.key))
+		goto use_pp;
+
+	pkey  = KEY_OFFSET(p->node.key);
+	ppkey = KEY_OFFSET(pp->node.key);
+
+	if (pkey < NOW_OFFSET_BOUNDARY())
+		pkey += 0x100000; // key in the future
+
+	if (ppkey < NOW_OFFSET_BOUNDARY())
+		ppkey += 0x100000; // key in the future
+
+	if (pkey <= ppkey)
+		goto use_p;
+
+ use_pp:
+	/* we'd like to release the proxy lock ASAP to let other threads
+	 * work with other servers. But for this we must first hold the
+	 * pendconn alive to prevent a removal from its owning stream.
+	 */
+	HA_SPIN_LOCK(QUEUE_LOCK, &pp->del_lock);
+
+	/* now the element won't go, we can release the proxy */
+	__pendconn_unlink_prx(pp);
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &px->queue.lock);
+
+	pp->strm_flags |= SF_ASSIGNED;
+	pp->target = srv;
+	stream_add_srv_conn(pp->strm, srv);
+
+	/* we must wake the task up before releasing the lock as it's the only
+	 * way to make sure the task still exists. The pendconn cannot vanish
+	 * under us since the task will need to take the lock anyway and to wait
+	 * if it wakes up on a different thread.
+	 */
+	task_wakeup(pp->strm->task, TASK_WOKEN_RES);
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &pp->del_lock);
+
+	_HA_ATOMIC_DEC(&px->queue.length);
+	_HA_ATOMIC_INC(&px->queue.idx);
+	return 1;
+
+ use_p:
+	/* we don't need the px queue lock anymore, we have the server's lock */
+	if (pp)
+		HA_SPIN_UNLOCK(QUEUE_LOCK, &px->queue.lock);
+
+	p->strm_flags |= SF_ASSIGNED;
+	p->target = srv;
+	stream_add_srv_conn(p->strm, srv);
+
+	/* we must wake the task up before releasing the lock as it's the only
+	 * way to make sure the task still exists. The pendconn cannot vanish
+	 * under us since the task will need to take the lock anyway and to wait
+	 * if it wakes up on a different thread.
+	 */
+	task_wakeup(p->strm->task, TASK_WOKEN_RES);
+	__pendconn_unlink_srv(p);
+
+	_HA_ATOMIC_DEC(&srv->queue.length);
+	_HA_ATOMIC_INC(&srv->queue.idx);
+	return 1;
+}
+
+/* Manages a server's connection queue. This function will try to dequeue as
+ * many pending streams as possible, and wake them up.
+ */
+void process_srv_queue(struct server *s)
+{
+	struct server *ref = s->track ? s->track : s;
+	struct proxy  *p = s->proxy;
+	int maxconn;
+	int stop = 0;
+	int done = 0;
+	int px_ok;
+
+	/* if a server is not usable or backup and must not be used
+	 * to dequeue backend requests.
+	 */
+	px_ok = srv_currently_usable(ref) &&
+	        (!(s->flags & SRV_F_BACKUP) ||
+	         (!p->srv_act &&
+	          (s == p->lbprm.fbck || (p->options & PR_O_USE_ALL_BK))));
+
+	/* let's repeat that under the lock on each round. Threads competing
+	 * for the same server will give up, knowing that at least one of
+	 * them will check the conditions again before quitting. In order
+	 * to avoid the deadly situation where one thread spends its time
+	 * dequeueing for others, we limit the number of rounds it does.
+	 * However we still re-enter the loop for one pass if there's no
+	 * more served, otherwise we could end up with no other thread
+	 * trying to dequeue them.
+	 */
+	while (!stop && (done < global.tune.maxpollevents || !s->served) &&
+	       s->served < (maxconn = srv_dynamic_maxconn(s))) {
+		if (HA_SPIN_TRYLOCK(QUEUE_LOCK, &s->queue.lock) != 0)
+			break;
+
+		while (s->served < maxconn) {
+			stop = !pendconn_process_next_strm(s, p, px_ok);
+			if (stop)
+				break;
+			_HA_ATOMIC_INC(&s->served);
+			done++;
+			if (done >= global.tune.maxpollevents)
+				break;
+		}
+		HA_SPIN_UNLOCK(QUEUE_LOCK, &s->queue.lock);
+	}
+
+	if (done) {
+		_HA_ATOMIC_SUB(&p->totpend, done);
+		_HA_ATOMIC_ADD(&p->served, done);
+		__ha_barrier_atomic_store();
+		if (p->lbprm.server_take_conn)
+			p->lbprm.server_take_conn(s);
+	}
+}
+
+/* Adds the stream <strm> to the pending connection queue of server <strm>->srv
+ * or to the one of <strm>->proxy if srv is NULL. All counters and back pointers
+ * are updated accordingly. Returns NULL if no memory is available, otherwise the
+ * pendconn itself. If the stream was already marked as served, its flag is
+ * cleared. It is illegal to call this function with a non-NULL strm->srv_conn.
+ * The stream's queue position is counted with an offset of -1 because we want
+ * to make sure that being at the first position in the queue reports 1.
+ *
+ * The queue is sorted by the composition of the priority_class, and the current
+ * timestamp offset by strm->priority_offset. The timestamp is in milliseconds
+ * and truncated to 20 bits, so will wrap every 17m28s575ms.
+ * The offset can be positive or negative, and an offset of 0 puts it in the
+ * middle of this range (~ 8 min). Note that this also means if the adjusted
+ * timestamp wraps around, the request will be misinterpreted as being of
+ * the highest priority for that priority class.
+ *
+ * This function must be called by the stream itself, so in the context of
+ * process_stream.
+ */
+struct pendconn *pendconn_add(struct stream *strm)
+{
+	struct pendconn *p;
+	struct proxy    *px;
+	struct server   *srv;
+	struct queue    *q;
+	unsigned int *max_ptr;
+	unsigned int old_max, new_max;
+
+	p = pool_alloc(pool_head_pendconn);
+	if (!p)
+		return NULL;
+
+	p->target     = NULL;
+	p->node.key   = MAKE_KEY(strm->priority_class, strm->priority_offset);
+	p->strm       = strm;
+	p->strm_flags = strm->flags;
+	HA_SPIN_INIT(&p->del_lock);
+	strm->pend_pos = p;
+
+	px = strm->be;
+	if (strm->flags & SF_ASSIGNED)
+		srv = objt_server(strm->target);
+	else
+		srv = NULL;
+
+	if (srv) {
+		q = &srv->queue;
+		max_ptr = &srv->counters.nbpend_max;
+	}
+	else {
+		q = &px->queue;
+		max_ptr = &px->be_counters.nbpend_max;
+	}
+
+	p->queue = q;
+	p->queue_idx  = _HA_ATOMIC_LOAD(&q->idx) - 1; // for logging only
+	new_max = _HA_ATOMIC_ADD_FETCH(&q->length, 1);
+	old_max = _HA_ATOMIC_LOAD(max_ptr);
+	while (new_max > old_max) {
+		if (likely(_HA_ATOMIC_CAS(max_ptr, &old_max, new_max)))
+			break;
+	}
+	__ha_barrier_atomic_store();
+
+	HA_SPIN_LOCK(QUEUE_LOCK, &q->lock);
+	eb32_insert(&q->head, &p->node);
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &q->lock);
+
+	_HA_ATOMIC_INC(&px->totpend);
+	return p;
+}
+
+/* Redistribute pending connections when a server goes down. The number of
+ * connections redistributed is returned. It will take the server queue lock
+ * and does not use nor depend on other locks.
+ */
+int pendconn_redistribute(struct server *s)
+{
+	struct pendconn *p;
+	struct eb32_node *node, *nodeb;
+	int xferred = 0;
+
+	/* The REDISP option was specified. We will ignore cookie and force to
+	 * balance or use the dispatcher. */
+	if ((s->proxy->options & (PR_O_REDISP|PR_O_PERSIST)) != PR_O_REDISP)
+		return 0;
+
+	HA_SPIN_LOCK(QUEUE_LOCK, &s->queue.lock);
+	for (node = eb32_first(&s->queue.head); node; node = nodeb) {
+		nodeb =	eb32_next(node);
+
+		p = eb32_entry(node, struct pendconn, node);
+		if (p->strm_flags & SF_FORCE_PRST)
+			continue;
+
+		/* it's left to the dispatcher to choose a server */
+		__pendconn_unlink_srv(p);
+		p->strm_flags &= ~(SF_DIRECT | SF_ASSIGNED);
+
+		task_wakeup(p->strm->task, TASK_WOKEN_RES);
+		xferred++;
+	}
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &s->queue.lock);
+
+	if (xferred) {
+		_HA_ATOMIC_SUB(&s->queue.length, xferred);
+		_HA_ATOMIC_SUB(&s->proxy->totpend, xferred);
+	}
+	return xferred;
+}
+
+/* Check for pending connections at the backend, and assign some of them to
+ * the server coming up. The server's weight is checked before being assigned
+ * connections it may not be able to handle. The total number of transferred
+ * connections is returned. It will take the proxy's queue lock and will not
+ * use nor depend on other locks.
+ */
+int pendconn_grab_from_px(struct server *s)
+{
+	struct pendconn *p;
+	int maxconn, xferred = 0;
+
+	if (!srv_currently_usable(s))
+		return 0;
+
+	/* if this is a backup server and there are active servers or at
+	 * least another backup server was elected, then this one must
+	 * not dequeue requests from the proxy.
+	 */
+	if ((s->flags & SRV_F_BACKUP) &&
+	    (s->proxy->srv_act ||
+	     ((s != s->proxy->lbprm.fbck) && !(s->proxy->options & PR_O_USE_ALL_BK))))
+		return 0;
+
+	HA_SPIN_LOCK(QUEUE_LOCK, &s->proxy->queue.lock);
+	maxconn = srv_dynamic_maxconn(s);
+	while ((p = pendconn_first(&s->proxy->queue.head))) {
+		if (s->maxconn && s->served + xferred >= maxconn)
+			break;
+
+		__pendconn_unlink_prx(p);
+		p->target = s;
+
+		task_wakeup(p->strm->task, TASK_WOKEN_RES);
+		xferred++;
+	}
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &s->proxy->queue.lock);
+	if (xferred) {
+		_HA_ATOMIC_SUB(&s->proxy->queue.length, xferred);
+		_HA_ATOMIC_SUB(&s->proxy->totpend, xferred);
+	}
+	return xferred;
+}
+
+/* Try to dequeue pending connection attached to the stream <strm>. It must
+ * always exists here. If the pendconn is still linked to the server or the
+ * proxy queue, nothing is done and the function returns 1. Otherwise,
+ * <strm>->flags and <strm>->target are updated, the pendconn is released and 0
+ * is returned.
+ *
+ * This function must be called by the stream itself, so in the context of
+ * process_stream.
+ */
+int pendconn_dequeue(struct stream *strm)
+{
+	struct pendconn *p;
+	int is_unlinked;
+
+	/* unexpected case because it is called by the stream itself and
+	 * only the stream can release a pendconn. So it is only
+	 * possible if a pendconn is released by someone else or if the
+	 * stream is supposed to be queued but without its associated
+	 * pendconn. In both cases it is a bug! */
+	BUG_ON(!strm->pend_pos);
+
+	p = strm->pend_pos;
+
+	/* note below : we need to grab the queue's lock to check for emptiness
+	 * because we don't want a partial _grab_from_px() or _redistribute()
+	 * to be called in parallel and show an empty list without having the
+	 * time to finish. With this we know that if we see the element
+	 * unlinked, these functions were completely done.
+	 */
+	pendconn_queue_lock(p);
+	is_unlinked = !p->node.node.leaf_p;
+	pendconn_queue_unlock(p);
+
+	/* serialize to make sure the element was finished processing */
+	HA_SPIN_LOCK(QUEUE_LOCK, &p->del_lock);
+	HA_SPIN_UNLOCK(QUEUE_LOCK, &p->del_lock);
+
+	if (!is_unlinked)
+		return 1;
+
+	/* the pendconn is not queued anymore and will not be so we're safe
+	 * to proceed.
+	 */
+	strm->flags &= ~(SF_DIRECT | SF_ASSIGNED);
+	strm->flags |= p->strm_flags & (SF_DIRECT | SF_ASSIGNED);
+
+	/* the entry might have been redistributed to another server */
+	if (!(strm->flags & SF_ASSIGNED))
+		sockaddr_free(&strm->scb->dst);
+
+	if (p->target) {
+		/* a server picked this pendconn, it must skip LB */
+		strm->target = &p->target->obj_type;
+		strm->flags |= SF_ASSIGNED;
+	}
+
+	strm->pend_pos = NULL;
+	pool_free(pool_head_pendconn, p);
+	return 0;
+}
+
+static enum act_return action_set_priority_class(struct act_rule *rule, struct proxy *px,
+                                                 struct session *sess, struct stream *s, int flags)
+{
+	struct sample *smp;
+
+	smp = sample_fetch_as_type(px, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->arg.expr, SMP_T_SINT);
+	if (!smp)
+		return ACT_RET_CONT;
+
+	s->priority_class = queue_limit_class(smp->data.u.sint);
+	return ACT_RET_CONT;
+}
+
+static enum act_return action_set_priority_offset(struct act_rule *rule, struct proxy *px,
+                                                  struct session *sess, struct stream *s, int flags)
+{
+	struct sample *smp;
+
+	smp = sample_fetch_as_type(px, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->arg.expr, SMP_T_SINT);
+	if (!smp)
+		return ACT_RET_CONT;
+
+	s->priority_offset = queue_limit_offset(smp->data.u.sint);
+
+	return ACT_RET_CONT;
+}
+
+static enum act_parse_ret parse_set_priority_class(const char **args, int *arg, struct proxy *px,
+                                                   struct act_rule *rule, char **err)
+{
+	unsigned int where = 0;
+
+	rule->arg.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
+	                                   px->conf.args.line, err, &px->conf.args, NULL);
+	if (!rule->arg.expr)
+		return ACT_RET_PRS_ERR;
+
+	if (px->cap & PR_CAP_FE)
+		where |= SMP_VAL_FE_HRQ_HDR;
+	if (px->cap & PR_CAP_BE)
+		where |= SMP_VAL_BE_HRQ_HDR;
+
+	if (!(rule->arg.expr->fetch->val & where)) {
+		memprintf(err,
+			  "fetch method '%s' extracts information from '%s', none of which is available here",
+			  args[0], sample_src_names(rule->arg.expr->fetch->use));
+		free(rule->arg.expr);
+		return ACT_RET_PRS_ERR;
+	}
+
+	rule->action     = ACT_CUSTOM;
+	rule->action_ptr = action_set_priority_class;
+	return ACT_RET_PRS_OK;
+}
+
+static enum act_parse_ret parse_set_priority_offset(const char **args, int *arg, struct proxy *px,
+                                                    struct act_rule *rule, char **err)
+{
+	unsigned int where = 0;
+
+	rule->arg.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
+	                                   px->conf.args.line, err, &px->conf.args, NULL);
+	if (!rule->arg.expr)
+		return ACT_RET_PRS_ERR;
+
+	if (px->cap & PR_CAP_FE)
+		where |= SMP_VAL_FE_HRQ_HDR;
+	if (px->cap & PR_CAP_BE)
+		where |= SMP_VAL_BE_HRQ_HDR;
+
+	if (!(rule->arg.expr->fetch->val & where)) {
+		memprintf(err,
+			  "fetch method '%s' extracts information from '%s', none of which is available here",
+			  args[0], sample_src_names(rule->arg.expr->fetch->use));
+		free(rule->arg.expr);
+		return ACT_RET_PRS_ERR;
+	}
+
+	rule->action     = ACT_CUSTOM;
+	rule->action_ptr = action_set_priority_offset;
+	return ACT_RET_PRS_OK;
+}
+
+static struct action_kw_list tcp_cont_kws = {ILH, {
+	{ "set-priority-class", parse_set_priority_class },
+	{ "set-priority-offset", parse_set_priority_offset },
+	{ /* END */ }
+}};
+
+INITCALL1(STG_REGISTER, tcp_req_cont_keywords_register, &tcp_cont_kws);
+
+static struct action_kw_list http_req_kws = {ILH, {
+	{ "set-priority-class", parse_set_priority_class },
+	{ "set-priority-offset", parse_set_priority_offset },
+	{ /* END */ }
+}};
+
+INITCALL1(STG_REGISTER, http_req_keywords_register, &http_req_kws);
+
+static int
+smp_fetch_priority_class(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+	if (!smp->strm)
+		return 0;
+
+	smp->data.type = SMP_T_SINT;
+	smp->data.u.sint = smp->strm->priority_class;
+
+	return 1;
+}
+
+static int
+smp_fetch_priority_offset(const struct arg *args, struct sample *smp, const char *kw, void *private)
+{
+	if (!smp->strm)
+		return 0;
+
+	smp->data.type = SMP_T_SINT;
+	smp->data.u.sint = smp->strm->priority_offset;
+
+	return 1;
+}
+
+
+static struct sample_fetch_kw_list smp_kws = {ILH, {
+	{ "prio_class", smp_fetch_priority_class, 0, NULL, SMP_T_SINT, SMP_USE_INTRN, },
+	{ "prio_offset", smp_fetch_priority_offset, 0, NULL, SMP_T_SINT, SMP_USE_INTRN, },
+	{ /* END */},
+}};
+
+INITCALL1(STG_REGISTER, sample_register_fetches, &smp_kws);
+
+/*
+ * Local variables:
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ * End:
+ */