2011/2/8 Jack Vogel <jfvo...@gmail.com>
>
> I have been following this, and thinking about it. I still am working from
> a theoretical
> standpoint, but based on a patch I got quite a long time back and never
> quite groked,
> I believe now that I might have a solution.
>
> The original PR and patch was kern/150516 from Beezar Liu, I was never
> quite comfortable
> with the code changes, nor convinced that it was a real issue and not a
> misunderstanding.
> However I think now that this very report might be behind what we are
> seeing today. I have
> a slightly different approach to solving it, of course it remains to be
> seen if it handles it
> properly.
>
> Please try the patch I've attached, I'm open to further correction or
> polishing of the
> changes. And thanks to Beezar for his original report and changes, this is
> not for em,
> but if this eliminates the problem its clearly needed in all drivers.
>
> Jack
>
>
> Hi Jack,
Thanks for your help. I tried your patch and it didn't work so I added a
couple of printf to see if the added code was getting hit:
--- a/freebsd/sys/dev/e1000/if_igb.c
--More--(byte 1253)+++ b/freebsd/sys/dev/e1000/if_igb.c
@@ -612,7 +612,7 @@ igb_attach(device_t dev)
device_get_nameunit(dev));
INIT_DEBUGOUT("igb_attach: end");
-
+ printf("this driver has a patch from Jack Vogel\n");
return (0);
err_late:
@@ -4131,6 +4131,7 @@ igb_rxeof(struct igb_queue *que, int count, int *done)
struct mbuf *sendmp, *mh, *mp;
struct igb_rx_buf *rxbuf;
u16 hlen, plen, hdr, vtag;
+ int commit;
bool eop = FALSE;
cur = &rxr->rx_base[i];
@@ -4255,10 +4256,23 @@ next_desc:
bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map,
BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
+ commit = i; /* capture the old index */
+
/* Advance our pointers to the next descriptor. */
if (++i == adapter->num_rx_desc)
i = 0;
/*
+ ** Sanity test for ring full, if this
+ ** happens we need to refresh immediately
+ ** or refresh may deadlock.
+ */
+ if (i == rxr->next_to_refresh) {
+ igb_refresh_mbufs(rxr, commit);
+ printf("igb_refresh_mbufs called with commit %d\n",
commit);
+ processed = 0;
+ }
+
+ /*
** Send to the stack or LRO
*/
if (sendmp != NULL) {
Here is the results:
# dmesg | grep Vogel
this driver has a patch from Jack Vogel
this driver has a patch from Jack Vogel
# netstat -m
60453/52707/113160 mbufs in use (current/cache/total)
48416/51584/100000/100000 mbuf clusters in use (current/cache/total/max)
2894/690 mbuf+clusters out of packet secondary zone in use (current/cache)
11946/854/12800/12800 4k (page size) jumbo clusters in use
(current/cache/total/max)
0/0/0/6400 9k jumbo clusters in use (current/cache/total/max)
0/0/0/3200 16k jumbo clusters in use (current/cache/total/max)
164834K/119760K/284595K bytes allocated to network (current/cache/total)
0/339/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/4/6656 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines
# dmesg | grep commit
At this point RX has hung.
Somehow the check (i == rxr->next_to_refresh) is never true in this case.
Also, I did read kern/150516 and couldn't wrap my head around the patch for
the em driver that Beezar Liu suggested.
Regards,
Karim.
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