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Date:      Wed, 6 Sep 2017 13:56:18 +0000 (UTC)
From:      Hans Petter Selasky <hselasky@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r323219 - in head/sys: net netinet
Message-ID:  <201709061356.v86DuIjQ074932@repo.freebsd.org>
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Author: hselasky
Date: Wed Sep  6 13:56:18 2017
New Revision: 323219
URL: https://svnweb.freebsd.org/changeset/base/323219

Log:
  Add support for generic backpressure indicator for ratelimited
  transmit queues aswell as non-ratelimited ones.
  
  Add the required structure bits in order to support a backpressure
  indication with ratelimited connections aswell as non-ratelimited
  ones. The backpressure indicator is a value between zero and 65535
  inclusivly, indicating if the destination transmit queue is empty or
  full respectivly. Applications can use this value as a decision point
  for when to stop transmitting data to avoid endless ENOBUFS error
  codes upon transmitting an mbuf. This indicator is also useful to
  reduce the latency for ratelimited queues.
  
  Reviewed by:		gallatin, kib, gnn
  Differential Revision:	https://reviews.freebsd.org/D11518
  Sponsored by:		Mellanox Technologies

Modified:
  head/sys/net/if_var.h
  head/sys/netinet/in_pcb.c
  head/sys/netinet/in_pcb.h

Modified: head/sys/net/if_var.h
==============================================================================
--- head/sys/net/if_var.h	Wed Sep  6 13:10:33 2017	(r323218)
+++ head/sys/net/if_var.h	Wed Sep  6 13:56:18 2017	(r323219)
@@ -183,7 +183,8 @@ struct if_encap_req {
 struct m_snd_tag;
 
 #define	IF_SND_TAG_TYPE_RATE_LIMIT 0
-#define	IF_SND_TAG_TYPE_MAX 1
+#define	IF_SND_TAG_TYPE_UNLIMITED 1
+#define	IF_SND_TAG_TYPE_MAX 2
 
 struct if_snd_tag_alloc_header {
 	uint32_t type;		/* send tag type, see IF_SND_TAG_XXX */
@@ -198,19 +199,26 @@ struct if_snd_tag_alloc_rate_limit {
 
 struct if_snd_tag_rate_limit_params {
 	uint64_t max_rate;	/* in bytes/s */
+	uint32_t queue_level;	/* 0 (empty) .. 65535 (full) */
+#define	IF_SND_QUEUE_LEVEL_MIN 0
+#define	IF_SND_QUEUE_LEVEL_MAX 65535
+	uint32_t reserved;	/* padding */
 };
 
 union if_snd_tag_alloc_params {
 	struct if_snd_tag_alloc_header hdr;
 	struct if_snd_tag_alloc_rate_limit rate_limit;
+	struct if_snd_tag_alloc_rate_limit unlimited;
 };
 
 union if_snd_tag_modify_params {
 	struct if_snd_tag_rate_limit_params rate_limit;
+	struct if_snd_tag_rate_limit_params unlimited;
 };
 
 union if_snd_tag_query_params {
 	struct if_snd_tag_rate_limit_params rate_limit;
+	struct if_snd_tag_rate_limit_params unlimited;
 };
 
 typedef int (if_snd_tag_alloc_t)(struct ifnet *, union if_snd_tag_alloc_params *,

Modified: head/sys/netinet/in_pcb.c
==============================================================================
--- head/sys/netinet/in_pcb.c	Wed Sep  6 13:10:33 2017	(r323218)
+++ head/sys/netinet/in_pcb.c	Wed Sep  6 13:56:18 2017	(r323219)
@@ -2797,6 +2797,35 @@ in_pcbquery_txrtlmt(struct inpcb *inp, uint32_t *p_max
 }
 
 /*
+ * Query existing TX queue level based on the existing
+ * "inp->inp_snd_tag", if any.
+ */
+int
+in_pcbquery_txrlevel(struct inpcb *inp, uint32_t *p_txqueue_level)
+{
+	union if_snd_tag_query_params params = { };
+	struct m_snd_tag *mst;
+	struct ifnet *ifp;
+	int error;
+
+	mst = inp->inp_snd_tag;
+	if (mst == NULL)
+		return (EINVAL);
+
+	ifp = mst->ifp;
+	if (ifp == NULL)
+		return (EINVAL);
+
+	if (ifp->if_snd_tag_query == NULL)
+		return (EOPNOTSUPP);
+
+	error = ifp->if_snd_tag_query(mst, &params);
+	if (error == 0 &&  p_txqueue_level != NULL)
+		*p_txqueue_level = params.rate_limit.queue_level;
+	return (error);
+}
+
+/*
  * Allocate a new TX rate limit send tag from the network interface
  * given by the "ifp" argument and save it in "inp->inp_snd_tag":
  */
@@ -2805,7 +2834,8 @@ in_pcbattach_txrtlmt(struct inpcb *inp, struct ifnet *
     uint32_t flowtype, uint32_t flowid, uint32_t max_pacing_rate)
 {
 	union if_snd_tag_alloc_params params = {
-		.rate_limit.hdr.type = IF_SND_TAG_TYPE_RATE_LIMIT,
+		.rate_limit.hdr.type = (max_pacing_rate == -1U) ?
+		    IF_SND_TAG_TYPE_UNLIMITED : IF_SND_TAG_TYPE_RATE_LIMIT,
 		.rate_limit.hdr.flowid = flowid,
 		.rate_limit.hdr.flowtype = flowtype,
 		.rate_limit.max_rate = max_pacing_rate,

Modified: head/sys/netinet/in_pcb.h
==============================================================================
--- head/sys/netinet/in_pcb.h	Wed Sep  6 13:10:33 2017	(r323218)
+++ head/sys/netinet/in_pcb.h	Wed Sep  6 13:56:18 2017	(r323219)
@@ -761,6 +761,7 @@ int	in_pcbattach_txrtlmt(struct inpcb *, struct ifnet 
 void	in_pcbdetach_txrtlmt(struct inpcb *);
 int	in_pcbmodify_txrtlmt(struct inpcb *, uint32_t);
 int	in_pcbquery_txrtlmt(struct inpcb *, uint32_t *);
+int	in_pcbquery_txrlevel(struct inpcb *, uint32_t *);
 void	in_pcboutput_txrtlmt(struct inpcb *, struct ifnet *, struct mbuf *);
 void	in_pcboutput_eagain(struct inpcb *);
 #endif

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