---

yaml
---
r: 346475
b: refs/heads/master
c: 3a0c40d
h: refs/heads/master
i:
  346473: 271f2d8
  346471: a14444f
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 667be1e757f5684576d01d7402907a2489b1402f
+refs/heads/master: 3a0c40d2d29e476ece583540e4f11276e0f36d5f

trunk/drivers/block/aoe/aoe.h

@@ -86,8 +86,11 @@ enum {
 	NFACTIVE = 61,
 
 	TIMERTICK = HZ / 10,
-	MINTIMER = HZ >> 2,
+	RTTSCALE = 8,
+	RTTDSCALE = 3,
 	MAXTIMER = HZ << 1,
+	RTTAVG_INIT = HZ / 4 << RTTSCALE,
+	RTTDEV_INIT = RTTAVG_INIT / 4,
 };
 
 struct buf {
@@ -127,10 +130,11 @@ struct aoetgt {
 	struct list_head ffree;			/* list of free frames */
 	struct aoeif ifs[NAOEIFS];
 	struct aoeif *ifp;	/* current aoeif in use */
-	ushort nout;
+	ushort nout;		/* value of nout when skb was sent */
 	ushort maxout;		/* current value for max outstanding */
+	ushort next_cwnd;	/* incr maxout after decrementing to zero */
+	ushort ssthresh;	/* slow start threshold */
 	ulong falloc;		/* number of allocated frames */
-	ulong lastwadj;		/* last window adjustment */
 	int minbcnt;
 	int wpkts, rpkts;
 };
@@ -142,8 +146,8 @@ struct aoedev {
 	u16 aoeminor;
 	u16 flags;
 	u16 nopen;		/* (bd_openers isn't available without sleeping) */
-	u16 rttavg;		/* round trip average of requests/responses */
-	u16 mintimer;
+	u16 rttavg;		/* scaled AoE round trip time average */
+	u16 rttdev;		/* scaled round trip time mean deviation */
 	u16 fw_ver;		/* version of blade's firmware */
 	u16 lasttag;		/* last tag sent */
 	u16 useme;
@@ -164,6 +168,7 @@ struct aoedev {
 	} ip;
 	ulong maxbcnt;
 	struct list_head factive[NFACTIVE];	/* hash of active frames */
+	struct list_head rexmitq; /* deferred retransmissions */
 	struct aoetgt *targets[NTARGETS];
 	struct aoetgt **tgt;	/* target in use when working */
 	struct aoetgt *htgt;	/* target needing rexmit assistance */
@@ -196,6 +201,7 @@ void aoecmd_cfg(ushort aoemajor, unsigned char aoeminor);
 struct sk_buff *aoecmd_ata_rsp(struct sk_buff *);
 void aoecmd_cfg_rsp(struct sk_buff *);
 void aoecmd_sleepwork(struct work_struct *);
+void aoecmd_wreset(struct aoetgt *t);
 void aoecmd_cleanslate(struct aoedev *);
 void aoecmd_exit(void);
 int aoecmd_init(void);

trunk/drivers/block/aoe/aoecmd.c

@@ -58,6 +58,23 @@ new_skb(ulong len)
 	return skb;
 }
 
+static struct frame *
+getframe_deferred(struct aoedev *d, u32 tag)
+{
+	struct list_head *head, *pos, *nx;
+	struct frame *f;
+
+	head = &d->rexmitq;
+	list_for_each_safe(pos, nx, head) {
+		f = list_entry(pos, struct frame, head);
+		if (f->tag == tag) {
+			list_del(pos);
+			return f;
+		}
+	}
+	return NULL;
+}
+
 static struct frame *
 getframe(struct aoedev *d, u32 tag)
 {
@@ -552,11 +569,30 @@ sthtith(struct aoedev *d)
 	return 1;
 }
 
+static void
+rexmit_deferred(struct aoedev *d)
+{
+	struct aoetgt *t;
+	struct frame *f;
+	struct list_head *pos, *nx, *head;
+
+	head = &d->rexmitq;
+	list_for_each_safe(pos, nx, head) {
+		f = list_entry(pos, struct frame, head);
+		t = f->t;
+		if (t->nout >= t->maxout)
+			continue;
+		list_del(pos);
+		t->nout++;
+		resend(d, f);
+	}
+}
+
 static void
 rexmit_timer(ulong vp)
 {
 	struct aoedev *d;
-	struct aoetgt *t, **tt, **te;
+	struct aoetgt *t;
 	struct aoeif *ifp;
 	struct frame *f;
 	struct list_head *head, *pos, *nx;
@@ -567,9 +603,11 @@ rexmit_timer(ulong vp)
 
 	d = (struct aoedev *) vp;
 
-	/* timeout is always ~150% of the moving average */
-	timeout = d->rttavg;
-	timeout += timeout >> 1;
+	/* timeout based on observed timings and variations */
+	timeout = 2 * d->rttavg >> RTTSCALE;
+	timeout += 8 * d->rttdev >> RTTDSCALE;
+	if (timeout == 0)
+		timeout = 1;
 
 	spin_lock_irqsave(&d->lock, flags);
 
@@ -589,29 +627,12 @@ rexmit_timer(ulong vp)
 			list_move_tail(pos, &flist);
 		}
 	}
-	/* window check */
-	tt = d->targets;
-	te = tt + d->ntargets;
-	for (; tt < te && (t = *tt); tt++) {
-		if (t->nout == t->maxout
-		&& t->maxout < t->nframes
-		&& (jiffies - t->lastwadj)/HZ > 10) {
-			t->maxout++;
-			t->lastwadj = jiffies;
-		}
-	}
-
-	if (!list_empty(&flist)) {	/* retransmissions necessary */
-		n = d->rttavg <<= 1;
-		if (n > MAXTIMER)
-			d->rttavg = MAXTIMER;
-	}
 
 	/* process expired frames */
 	while (!list_empty(&flist)) {
 		pos = flist.next;
 		f = list_entry(pos, struct frame, head);
-		n = f->waited += timeout;
+		n = f->waited += tsince(f->tag);
 		n /= HZ;
 		if (n > aoe_deadsecs) {
 			/* Waited too long.  Device failure.
@@ -620,18 +641,16 @@ rexmit_timer(ulong vp)
 			 */
 			list_splice(&flist, &d->factive[0]);
 			aoedev_downdev(d);
-			break;
+			goto out;
 		}
-		list_del(pos);
 
 		t = f->t;
 		if (n > aoe_deadsecs/2)
 			d->htgt = t; /* see if another target can help */
 
-		if (t->nout == t->maxout) {
-			if (t->maxout > 1)
-				t->maxout--;
-			t->lastwadj = jiffies;
+		if (t->maxout != 1) {
+			t->ssthresh = t->maxout / 2;
+			t->maxout = 1;
 		}
 
 		ifp = getif(t, f->skb->dev);
@@ -640,9 +659,12 @@ rexmit_timer(ulong vp)
 			ejectif(t, ifp);
 			ifp = NULL;
 		}
-		resend(d, f);
+		list_move_tail(pos, &d->rexmitq);
+		t->nout--;
 	}
+	rexmit_deferred(d);
 
+out:
 	if ((d->flags & DEVFL_KICKME || d->htgt) && d->blkq) {
 		d->flags &= ~DEVFL_KICKME;
 		d->blkq->request_fn(d->blkq);
@@ -766,6 +788,7 @@ aoecmd_work(struct aoedev *d)
 {
 	if (d->htgt && !sthtith(d))
 		return;
+	rexmit_deferred(d);
 	while (aoecmd_ata_rw(d))
 		;
 }
@@ -868,26 +891,28 @@ ataid_complete(struct aoedev *d, struct aoetgt *t, unsigned char *id)
 }
 
 static void
-calc_rttavg(struct aoedev *d, int rtt)
+calc_rttavg(struct aoedev *d, struct aoetgt *t, int rtt)
 {
 	register long n;
 
 	n = rtt;
-	if (n < 0) {
-		n = -rtt;
-		if (n < MINTIMER)
-			n = MINTIMER;
-		else if (n > MAXTIMER)
-			n = MAXTIMER;
-		d->mintimer += (n - d->mintimer) >> 1;
-	} else if (n < d->mintimer)
-		n = d->mintimer;
-	else if (n > MAXTIMER)
-		n = MAXTIMER;
-
-	/* g == .25; cf. Congestion Avoidance and Control, Jacobson & Karels; 1988 */
-	n -= d->rttavg;
-	d->rttavg += n >> 2;
+
+	/* cf. Congestion Avoidance and Control, Jacobson & Karels, 1988 */
+	n -= d->rttavg >> RTTSCALE;
+	d->rttavg += n;
+	if (n < 0)
+		n = -n;
+	n -= d->rttdev >> RTTDSCALE;
+	d->rttdev += n;
+
+	if (!t || t->maxout >= t->nframes)
+		return;
+	if (t->maxout < t->ssthresh)
+		t->maxout += 1;
+	else if (t->nout == t->maxout && t->next_cwnd-- == 0) {
+		t->maxout += 1;
+		t->next_cwnd = t->maxout;
+	}
 }
 
 static struct aoetgt *
@@ -1147,7 +1172,6 @@ aoecmd_ata_rsp(struct sk_buff *skb)
 	struct aoedev *d;
 	struct aoe_hdr *h;
 	struct frame *f;
-	struct aoetgt *t;
 	u32 n;
 	ulong flags;
 	char ebuf[128];
@@ -1168,23 +1192,28 @@ aoecmd_ata_rsp(struct sk_buff *skb)
 
 	n = be32_to_cpu(get_unaligned(&h->tag));
 	f = getframe(d, n);
-	if (f == NULL) {
-		calc_rttavg(d, -tsince(n));
-		spin_unlock_irqrestore(&d->lock, flags);
-		aoedev_put(d);
-		snprintf(ebuf, sizeof ebuf,
-			"%15s e%d.%d    tag=%08x@%08lx\n",
-			"unexpected rsp",
-			get_unaligned_be16(&h->major),
-			h->minor,
-			get_unaligned_be32(&h->tag),
-			jiffies);
-		aoechr_error(ebuf);
-		return skb;
+	if (f) {
+		calc_rttavg(d, f->t, tsince(n));
+		f->t->nout--;
+	} else {
+		f = getframe_deferred(d, n);
+		if (f) {
+			calc_rttavg(d, NULL, tsince(n));
+		} else {
+			calc_rttavg(d, NULL, tsince(n));
+			spin_unlock_irqrestore(&d->lock, flags);
+			aoedev_put(d);
+			snprintf(ebuf, sizeof(ebuf),
+				 "%15s e%d.%d    tag=%08x@%08lx\n",
+				 "unexpected rsp",
+				 get_unaligned_be16(&h->major),
+				 h->minor,
+				 get_unaligned_be32(&h->tag),
+				 jiffies);
+			aoechr_error(ebuf);
+			return skb;
+		}
 	}
-	t = f->t;
-	calc_rttavg(d, tsince(f->tag));
-	t->nout--;
 	aoecmd_work(d);
 
 	spin_unlock_irqrestore(&d->lock, flags);
@@ -1241,7 +1270,8 @@ aoecmd_ata_id(struct aoedev *d)
 
 	skb->dev = t->ifp->nd;
 
-	d->rttavg = MAXTIMER;
+	d->rttavg = RTTAVG_INIT;
+	d->rttdev = RTTDEV_INIT;
 	d->timer.function = rexmit_timer;
 
 	return skb_clone(skb, GFP_ATOMIC);
@@ -1273,7 +1303,7 @@ addtgt(struct aoedev *d, char *addr, ulong nframes)
 	t->d = d;
 	memcpy(t->addr, addr, sizeof t->addr);
 	t->ifp = t->ifs;
-	t->maxout = t->nframes;
+	aoecmd_wreset(t);
 	INIT_LIST_HEAD(&t->ffree);
 	return *tt = t;
 }
@@ -1382,7 +1412,7 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
 	if (t) {
 		t->nframes = n;
 		if (n < t->maxout)
-			t->maxout = n;
+			aoecmd_wreset(t);
 	} else {
 		t = addtgt(d, h->src, n);
 		if (!t)
@@ -1411,18 +1441,27 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
 	}
 }
 
+void
+aoecmd_wreset(struct aoetgt *t)
+{
+	t->maxout = 1;
+	t->ssthresh = t->nframes / 2;
+	t->next_cwnd = t->nframes;
+}
+
 void
 aoecmd_cleanslate(struct aoedev *d)
 {
 	struct aoetgt **t, **te;
 
-	d->mintimer = MINTIMER;
+	d->rttavg = RTTAVG_INIT;
+	d->rttdev = RTTDEV_INIT;
 	d->maxbcnt = 0;
 
 	t = d->targets;
 	te = t + NTARGETS;
 	for (; t < te && *t; t++)
-		(*t)->maxout = (*t)->nframes;
+		aoecmd_wreset(*t);
 }
 
 void

trunk/drivers/block/aoe/aoedev.c

@@ -198,7 +198,7 @@ aoedev_downdev(struct aoedev *d)
 	tt = d->targets;
 	te = tt + NTARGETS;
 	for (; tt < te && (t = *tt); tt++) {
-		t->maxout = t->nframes;
+		aoecmd_wreset(t);
 		t->nout = 0;
 	}
 
@@ -391,10 +391,12 @@ aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
 	d->ref = 1;
 	for (i = 0; i < NFACTIVE; i++)
 		INIT_LIST_HEAD(&d->factive[i]);
+	INIT_LIST_HEAD(&d->rexmitq);
 	d->sysminor = sysminor;
 	d->aoemajor = maj;
 	d->aoeminor = min;
-	d->mintimer = MINTIMER;
+	d->rttavg = RTTAVG_INIT;
+	d->rttdev = RTTDEV_INIT;
 	d->next = devlist;
 	devlist = d;
  out: