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authorEd Cashin <ecashin@coraid.com>2012-12-17 16:04:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-17 17:15:25 -0800
commitbbb44e30d07fdc111e34a5ec935b57521cea9499 (patch)
tree11dda6628c4d7719607891f287c12aa87f06855b /drivers/block/aoe/aoecmd.c
parentb91316f2b7bc0b1d128a9890a2a4895f7e1c74fc (diff)
downloadlinux-bbb44e30d07fdc111e34a5ec935b57521cea9499.tar.bz2
aoe: improve handling of misbehaving network paths
An AoE target can have multiple network ports used for AoE, and in the aoe driver, those are tracked by the aoetgt struct. These changes allow the aoe driver to handle network paths, or aoetgts, that are not working well, compared to the others. Paths that do not get responses despite the retransmission of AoE commands are marked as "tainted", and non-tainted paths are preferred. Meanwhile, the aoe driver attempts to "probe" the tainted path in the background by issuing reads of LBA 0 that are padded out to full (possibly jumbo-frame) size. If the probes get responses, then the path is "redeemed", and its taint is removed. This mechanism has been shown to be helpful in transparently handling and recovering from real-world network "brown outs" in ways that the earlier "shoot the help-needing target in the head" mechanism could not. Signed-off-by: Ed Cashin <ecashin@coraid.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/aoe/aoecmd.c')
-rw-r--r--drivers/block/aoe/aoecmd.c377
1 files changed, 258 insertions, 119 deletions
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 391dd8ee2009..000f7fb48841 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -22,6 +22,7 @@
#define MAXIOC (8192) /* default meant to avoid most soft lockups */
static void ktcomplete(struct frame *, struct sk_buff *);
+static int count_targets(struct aoedev *d, int *untainted);
static struct buf *nextbuf(struct aoedev *);
@@ -43,6 +44,8 @@ static struct {
spinlock_t lock;
} iocq;
+static struct page *empty_page;
+
static struct sk_buff *
new_skb(ulong len)
{
@@ -179,8 +182,10 @@ aoe_freetframe(struct frame *f)
t = f->t;
f->buf = NULL;
+ f->lba = 0;
f->bv = NULL;
f->r_skb = NULL;
+ f->flags = 0;
list_add(&f->head, &t->ffree);
}
@@ -234,20 +239,25 @@ newframe(struct aoedev *d)
struct frame *f;
struct aoetgt *t, **tt;
int totout = 0;
+ int use_tainted;
+ int has_untainted;
if (d->targets[0] == NULL) { /* shouldn't happen, but I'm paranoid */
printk(KERN_ERR "aoe: NULL TARGETS!\n");
return NULL;
}
tt = d->tgt; /* last used target */
- for (;;) {
+ for (use_tainted = 0, has_untainted = 0;;) {
tt++;
if (tt >= &d->targets[NTARGETS] || !*tt)
tt = d->targets;
t = *tt;
- totout += t->nout;
+ if (!t->taint) {
+ has_untainted = 1;
+ totout += t->nout;
+ }
if (t->nout < t->maxout
- && t != d->htgt
+ && (use_tainted || !t->taint)
&& t->ifp->nd) {
f = newtframe(d, t);
if (f) {
@@ -256,8 +266,12 @@ newframe(struct aoedev *d)
return f;
}
}
- if (tt == d->tgt) /* we've looped and found nada */
- break;
+ if (tt == d->tgt) { /* we've looped and found nada */
+ if (!use_tainted && !has_untainted)
+ use_tainted = 1;
+ else
+ break;
+ }
}
if (totout == 0) {
d->kicked++;
@@ -294,21 +308,68 @@ fhash(struct frame *f)
list_add_tail(&f->head, &d->factive[n]);
}
+static void
+ata_rw_frameinit(struct frame *f)
+{
+ struct aoetgt *t;
+ struct aoe_hdr *h;
+ struct aoe_atahdr *ah;
+ struct sk_buff *skb;
+ char writebit, extbit;
+
+ skb = f->skb;
+ h = (struct aoe_hdr *) skb_mac_header(skb);
+ ah = (struct aoe_atahdr *) (h + 1);
+ skb_put(skb, sizeof(*h) + sizeof(*ah));
+ memset(h, 0, skb->len);
+
+ writebit = 0x10;
+ extbit = 0x4;
+
+ t = f->t;
+ f->tag = aoehdr_atainit(t->d, t, h);
+ fhash(f);
+ t->nout++;
+ f->waited = 0;
+ f->waited_total = 0;
+ if (f->buf)
+ f->lba = f->buf->sector;
+
+ /* set up ata header */
+ ah->scnt = f->bcnt >> 9;
+ put_lba(ah, f->lba);
+ if (t->d->flags & DEVFL_EXT) {
+ ah->aflags |= AOEAFL_EXT;
+ } else {
+ extbit = 0;
+ ah->lba3 &= 0x0f;
+ ah->lba3 |= 0xe0; /* LBA bit + obsolete 0xa0 */
+ }
+ if (f->buf && bio_data_dir(f->buf->bio) == WRITE) {
+ skb_fillup(skb, f->bv, f->bv_off, f->bcnt);
+ ah->aflags |= AOEAFL_WRITE;
+ skb->len += f->bcnt;
+ skb->data_len = f->bcnt;
+ skb->truesize += f->bcnt;
+ t->wpkts++;
+ } else {
+ t->rpkts++;
+ writebit = 0;
+ }
+
+ ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
+ skb->dev = t->ifp->nd;
+}
+
static int
aoecmd_ata_rw(struct aoedev *d)
{
struct frame *f;
- struct aoe_hdr *h;
- struct aoe_atahdr *ah;
struct buf *buf;
struct aoetgt *t;
struct sk_buff *skb;
struct sk_buff_head queue;
ulong bcnt, fbcnt;
- char writebit, extbit;
-
- writebit = 0x10;
- extbit = 0x4;
buf = nextbuf(d);
if (buf == NULL)
@@ -343,50 +404,15 @@ aoecmd_ata_rw(struct aoedev *d)
} while (fbcnt);
/* initialize the headers & frame */
- skb = f->skb;
- h = (struct aoe_hdr *) skb_mac_header(skb);
- ah = (struct aoe_atahdr *) (h+1);
- skb_put(skb, sizeof *h + sizeof *ah);
- memset(h, 0, skb->len);
- f->tag = aoehdr_atainit(d, t, h);
- fhash(f);
- t->nout++;
- f->waited = 0;
- f->waited_total = 0;
f->buf = buf;
f->bcnt = bcnt;
- f->lba = buf->sector;
-
- /* set up ata header */
- ah->scnt = bcnt >> 9;
- put_lba(ah, buf->sector);
- if (d->flags & DEVFL_EXT) {
- ah->aflags |= AOEAFL_EXT;
- } else {
- extbit = 0;
- ah->lba3 &= 0x0f;
- ah->lba3 |= 0xe0; /* LBA bit + obsolete 0xa0 */
- }
- if (bio_data_dir(buf->bio) == WRITE) {
- skb_fillup(skb, f->bv, f->bv_off, bcnt);
- ah->aflags |= AOEAFL_WRITE;
- skb->len += bcnt;
- skb->data_len = bcnt;
- skb->truesize += bcnt;
- t->wpkts++;
- } else {
- t->rpkts++;
- writebit = 0;
- }
-
- ah->cmdstat = ATA_CMD_PIO_READ | writebit | extbit;
+ ata_rw_frameinit(f);
/* mark all tracking fields and load out */
buf->nframesout += 1;
buf->sector += bcnt >> 9;
- skb->dev = t->ifp->nd;
- skb = skb_clone(skb, GFP_ATOMIC);
+ skb = skb_clone(f->skb, GFP_ATOMIC);
if (skb) {
do_gettimeofday(&f->sent);
f->sent_jiffs = (u32) jiffies;
@@ -462,11 +488,14 @@ resend(struct aoedev *d, struct frame *f)
h = (struct aoe_hdr *) skb_mac_header(skb);
ah = (struct aoe_atahdr *) (h+1);
- snprintf(buf, sizeof buf,
- "%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x s=%pm d=%pm nout=%d\n",
- "retransmit", d->aoemajor, d->aoeminor, f->tag, jiffies, n,
- h->src, h->dst, t->nout);
- aoechr_error(buf);
+ if (!(f->flags & FFL_PROBE)) {
+ snprintf(buf, sizeof(buf),
+ "%15s e%ld.%d oldtag=%08x@%08lx newtag=%08x s=%pm d=%pm nout=%d\n",
+ "retransmit", d->aoemajor, d->aoeminor,
+ f->tag, jiffies, n,
+ h->src, h->dst, t->nout);
+ aoechr_error(buf);
+ }
f->tag = n;
fhash(f);
@@ -558,18 +587,18 @@ ejectif(struct aoetgt *t, struct aoeif *ifp)
}
static struct frame *
-reassign_frame(struct list_head *pos)
+reassign_frame(struct frame *f)
{
- struct frame *f;
struct frame *nf;
struct sk_buff *skb;
- f = list_entry(pos, struct frame, head);
nf = newframe(f->t->d);
if (!nf)
return NULL;
-
- list_del(pos);
+ if (nf->t == f->t) {
+ aoe_freetframe(nf);
+ return NULL;
+ }
skb = nf->skb;
nf->skb = f->skb;
@@ -583,52 +612,67 @@ reassign_frame(struct list_head *pos)
nf->sent = f->sent;
nf->sent_jiffs = f->sent_jiffs;
f->skb = skb;
- aoe_freetframe(f);
- f->t->nout--;
- nf->t->nout++;
return nf;
}
-static int
-sthtith(struct aoedev *d)
+static void
+probe(struct aoetgt *t)
{
- struct frame *f, *nf;
- struct list_head *nx, *pos, *head;
- struct aoetgt *ht = d->htgt;
- int i;
+ struct aoedev *d;
+ struct frame *f;
+ struct sk_buff *skb;
+ struct sk_buff_head queue;
+ size_t n, m;
+ int frag;
- /* look through the active and pending retransmit frames */
- for (i = 0; i < NFACTIVE; i++) {
- head = &d->factive[i];
- list_for_each_safe(pos, nx, head) {
- f = list_entry(pos, struct frame, head);
- if (f->t != ht)
- continue;
- nf = reassign_frame(pos);
- if (!nf)
- return 0;
- resend(d, nf);
- }
+ d = t->d;
+ f = newtframe(d, t);
+ if (!f) {
+ pr_err("%s %pm for e%ld.%d: %s\n",
+ "aoe: cannot probe remote address",
+ t->addr,
+ (long) d->aoemajor, d->aoeminor,
+ "no frame available");
+ return;
}
- head = &d->rexmitq;
- list_for_each_safe(pos, nx, head) {
- f = list_entry(pos, struct frame, head);
- if (f->t != ht)
- continue;
- nf = reassign_frame(pos);
- if (!nf)
- return 0;
- resend(d, nf);
+ f->flags |= FFL_PROBE;
+ ifrotate(t);
+ f->bcnt = t->d->maxbcnt ? t->d->maxbcnt : DEFAULTBCNT;
+ ata_rw_frameinit(f);
+ skb = f->skb;
+ for (frag = 0, n = f->bcnt; n > 0; ++frag, n -= m) {
+ if (n < PAGE_SIZE)
+ m = n;
+ else
+ m = PAGE_SIZE;
+ skb_fill_page_desc(skb, frag, empty_page, 0, m);
}
- /* We've cleaned up the outstanding so take away his
- * interfaces so he won't be used. We should remove him from
- * the target array here, but cleaning up a target is
- * involved. PUNT!
- */
- memset(ht->ifs, 0, sizeof ht->ifs);
- d->htgt = NULL;
- return 1;
+ skb->len += f->bcnt;
+ skb->data_len = f->bcnt;
+ skb->truesize += f->bcnt;
+
+ skb = skb_clone(f->skb, GFP_ATOMIC);
+ if (skb) {
+ do_gettimeofday(&f->sent);
+ f->sent_jiffs = (u32) jiffies;
+ __skb_queue_head_init(&queue);
+ __skb_queue_tail(&queue, skb);
+ aoenet_xmit(&queue);
+ }
+}
+
+static long
+rto(struct aoedev *d)
+{
+ long t;
+
+ t = 2 * d->rttavg >> RTTSCALE;
+ t += 8 * d->rttdev >> RTTDSCALE;
+ if (t == 0)
+ t = 1;
+
+ return t;
}
static void
@@ -636,17 +680,53 @@ rexmit_deferred(struct aoedev *d)
{
struct aoetgt *t;
struct frame *f;
+ struct frame *nf;
struct list_head *pos, *nx, *head;
int since;
+ int untainted;
+
+ count_targets(d, &untainted);
head = &d->rexmitq;
list_for_each_safe(pos, nx, head) {
f = list_entry(pos, struct frame, head);
t = f->t;
+ if (t->taint) {
+ if (!(f->flags & FFL_PROBE)) {
+ nf = reassign_frame(f);
+ if (nf) {
+ if (t->nout_probes == 0
+ && untainted > 0) {
+ probe(t);
+ t->nout_probes++;
+ }
+ list_replace(&f->head, &nf->head);
+ pos = &nf->head;
+ aoe_freetframe(f);
+ f = nf;
+ t = f->t;
+ }
+ } else if (untainted < 1) {
+ /* don't probe w/o other untainted aoetgts */
+ goto stop_probe;
+ } else if (tsince_hr(f) < t->taint * rto(d)) {
+ /* reprobe slowly when taint is high */
+ continue;
+ }
+ } else if (f->flags & FFL_PROBE) {
+stop_probe: /* don't probe untainted aoetgts */
+ list_del(pos);
+ aoe_freetframe(f);
+ /* leaving d->kicked, because this is routine */
+ f->t->d->flags |= DEVFL_KICKME;
+ continue;
+ }
if (t->nout >= t->maxout)
continue;
list_del(pos);
t->nout++;
+ if (f->flags & FFL_PROBE)
+ t->nout_probes++;
since = tsince_hr(f);
f->waited += since;
f->waited_total += since;
@@ -654,6 +734,36 @@ rexmit_deferred(struct aoedev *d)
}
}
+/* An aoetgt accumulates demerits quickly, and successful
+ * probing redeems the aoetgt slowly.
+ */
+static void
+scorn(struct aoetgt *t)
+{
+ int n;
+
+ n = t->taint++;
+ t->taint += t->taint * 2;
+ if (n > t->taint)
+ t->taint = n;
+ if (t->taint > MAX_TAINT)
+ t->taint = MAX_TAINT;
+}
+
+static int
+count_targets(struct aoedev *d, int *untainted)
+{
+ int i, good;
+
+ for (i = good = 0; i < d->ntargets && d->targets[i]; ++i)
+ if (d->targets[i]->taint == 0)
+ good++;
+
+ if (untainted)
+ *untainted = good;
+ return i;
+}
+
static void
rexmit_timer(ulong vp)
{
@@ -666,6 +776,7 @@ rexmit_timer(ulong vp)
register long timeout;
ulong flags, n;
int i;
+ int utgts; /* number of aoetgt descriptors (not slots) */
int since;
d = (struct aoedev *) vp;
@@ -673,10 +784,9 @@ rexmit_timer(ulong vp)
spin_lock_irqsave(&d->lock, flags);
/* timeout based on observed timings and variations */
- timeout = 2 * d->rttavg >> RTTSCALE;
- timeout += 8 * d->rttdev >> RTTDSCALE;
- if (timeout == 0)
- timeout = 1;
+ timeout = rto(d);
+
+ utgts = count_targets(d, NULL);
if (d->flags & DEVFL_TKILL) {
spin_unlock_irqrestore(&d->lock, flags);
@@ -702,7 +812,7 @@ rexmit_timer(ulong vp)
since = tsince_hr(f);
n = f->waited_total + since;
n /= USEC_PER_SEC;
- if (n > aoe_deadsecs) {
+ if (n > aoe_deadsecs && !(f->flags & FFL_PROBE)) {
/* Waited too long. Device failure.
* Hang all frames on first hash bucket for downdev
* to clean up.
@@ -713,19 +823,26 @@ rexmit_timer(ulong vp)
}
t = f->t;
- if (n > aoe_deadsecs/2)
- d->htgt = t; /* see if another target can help */
+ n = f->waited + since;
+ n /= USEC_PER_SEC;
+ if (aoe_deadsecs && utgts > 0
+ && (n > aoe_deadsecs / utgts || n > HARD_SCORN_SECS))
+ scorn(t); /* avoid this target */
if (t->maxout != 1) {
t->ssthresh = t->maxout / 2;
t->maxout = 1;
}
- ifp = getif(t, f->skb->dev);
- if (ifp && ++ifp->lost > (t->nframes << 1)
- && (ifp != t->ifs || t->ifs[1].nd)) {
- ejectif(t, ifp);
- ifp = NULL;
+ if (f->flags & FFL_PROBE) {
+ t->nout_probes--;
+ } else {
+ ifp = getif(t, f->skb->dev);
+ if (ifp && ++ifp->lost > (t->nframes << 1)
+ && (ifp != t->ifs || t->ifs[1].nd)) {
+ ejectif(t, ifp);
+ ifp = NULL;
+ }
}
list_move_tail(pos, &d->rexmitq);
t->nout--;
@@ -733,7 +850,7 @@ rexmit_timer(ulong vp)
rexmit_deferred(d);
out:
- if ((d->flags & DEVFL_KICKME || d->htgt) && d->blkq) {
+ if ((d->flags & DEVFL_KICKME) && d->blkq) {
d->flags &= ~DEVFL_KICKME;
d->blkq->request_fn(d->blkq);
}
@@ -854,8 +971,6 @@ nextbuf(struct aoedev *d)
void
aoecmd_work(struct aoedev *d)
{
- if (d->htgt && !sthtith(d))
- return;
rexmit_deferred(d);
while (aoecmd_ata_rw(d))
;
@@ -1065,19 +1180,22 @@ ktiocomplete(struct frame *f)
struct aoeif *ifp;
struct aoedev *d;
long n;
+ int untainted;
if (f == NULL)
return;
t = f->t;
d = t->d;
+ skb = f->r_skb;
+ buf = f->buf;
+ if (f->flags & FFL_PROBE)
+ goto out;
+ if (!skb) /* just fail the buf. */
+ goto noskb;
hout = (struct aoe_hdr *) skb_mac_header(f->skb);
ahout = (struct aoe_atahdr *) (hout+1);
- buf = f->buf;
- skb = f->r_skb;
- if (skb == NULL)
- goto noskb; /* just fail the buf. */
hin = (struct aoe_hdr *) skb->data;
skb_pull(skb, sizeof(*hin));
@@ -1089,7 +1207,7 @@ ktiocomplete(struct frame *f)
d->aoemajor, d->aoeminor);
noskb: if (buf)
clear_bit(BIO_UPTODATE, &buf->bio->bi_flags);
- goto badrsp;
+ goto out;
}
n = ahout->scnt << 9;
@@ -1109,8 +1227,6 @@ noskb: if (buf)
ifp = getif(t, skb->dev);
if (ifp)
ifp->lost = 0;
- if (d->htgt == t) /* I'll help myself, thank you. */
- d->htgt = NULL;
spin_unlock_irq(&d->lock);
break;
case ATA_CMD_ID_ATA:
@@ -1131,8 +1247,17 @@ noskb: if (buf)
be16_to_cpu(get_unaligned(&hin->major)),
hin->minor);
}
-badrsp:
+out:
spin_lock_irq(&d->lock);
+ if (t->taint > 0
+ && --t->taint > 0
+ && t->nout_probes == 0) {
+ count_targets(d, &untainted);
+ if (untainted > 0) {
+ probe(t);
+ t->nout_probes++;
+ }
+ }
aoe_freetframe(f);
@@ -1261,6 +1386,8 @@ aoecmd_ata_rsp(struct sk_buff *skb)
if (f) {
calc_rttavg(d, f->t, tsince_hr(f));
f->t->nout--;
+ if (f->flags & FFL_PROBE)
+ f->t->nout_probes--;
} else {
f = getframe_deferred(d, n);
if (f) {
@@ -1379,6 +1506,7 @@ addtgt(struct aoedev *d, char *addr, ulong nframes)
memcpy(t->addr, addr, sizeof t->addr);
t->ifp = t->ifs;
aoecmd_wreset(t);
+ t->maxout = t->nframes / 2;
INIT_LIST_HEAD(&t->ffree);
return *tt = t;
}
@@ -1584,6 +1712,14 @@ aoe_flush_iocq(void)
int __init
aoecmd_init(void)
{
+ void *p;
+
+ /* get_zeroed_page returns page with ref count 1 */
+ p = (void *) get_zeroed_page(GFP_KERNEL | __GFP_REPEAT);
+ if (!p)
+ return -ENOMEM;
+ empty_page = virt_to_page(p);
+
INIT_LIST_HEAD(&iocq.head);
spin_lock_init(&iocq.lock);
init_waitqueue_head(&ktiowq);
@@ -1599,4 +1735,7 @@ aoecmd_exit(void)
{
aoe_ktstop(&kts);
aoe_flush_iocq();
+
+ free_page((unsigned long) page_address(empty_page));
+ empty_page = NULL;
}