Module Name: src
Committed By: msaitoh
Date: Tue Mar 2 11:10:53 UTC 2021
Modified Files:
src/sys/dev/pci/ixgbe: ix_txrx.c
Log Message:
Fix jcl's starvation case in ixgbe_rxeof() again.
ix_txrx.c rev.1.64 preallocates jcl to prevent starvation but it's not
perfect. Don't use ixgbe_rx_discard() and just update the old descriptor
for reuse. It's also required for multiple descriptors case to refresh
subsequent descriptor(s). Reviewed by knakahara@.
To generate a diff of this commit:
cvs rdiff -u -r1.64 -r1.65 src/sys/dev/pci/ixgbe/ix_txrx.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/pci/ixgbe/ix_txrx.c
diff -u src/sys/dev/pci/ixgbe/ix_txrx.c:1.64 src/sys/dev/pci/ixgbe/ix_txrx.c:1.65
--- src/sys/dev/pci/ixgbe/ix_txrx.c:1.64 Mon Jan 18 09:09:04 2021
+++ src/sys/dev/pci/ixgbe/ix_txrx.c Tue Mar 2 11:10:53 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: ix_txrx.c,v 1.64 2021/01/18 09:09:04 knakahara Exp $ */
+/* $NetBSD: ix_txrx.c,v 1.65 2021/03/02 11:10:53 msaitoh Exp $ */
/******************************************************************************
@@ -1319,6 +1319,11 @@ ixgbe_setup_hw_rsc(struct rx_ring *rxr)
* exhaustion are unnecessary, if an mbuf cannot be obtained
* it just returns, keeping its placeholder, thus it can simply
* be recalled to try again.
+ *
+ * XXX NetBSD TODO:
+ * - The ixgbe_rxeof() function always preallocates mbuf cluster (jcl),
+ * so the ixgbe_refresh_mbufs() function can be simplified.
+ *
************************************************************************/
static void
ixgbe_refresh_mbufs(struct rx_ring *rxr, int limit)
@@ -1799,7 +1804,9 @@ ixgbe_rxeof(struct ix_queue *que)
struct ixgbe_rx_buf *rbuf, *nbuf;
int i, nextp, processed = 0;
u32 staterr = 0;
- u32 count = adapter->rx_process_limit;
+ u32 count = 0;
+ u32 limit = adapter->rx_process_limit;
+ bool discard_multidesc = false;
#ifdef RSS
u16 pkt_info;
#endif
@@ -1816,7 +1823,14 @@ ixgbe_rxeof(struct ix_queue *que)
}
#endif /* DEV_NETMAP */
- for (i = rxr->next_to_check; count != 0;) {
+ /*
+ * The max number of loop is rx_process_limit. If discard_multidesc is
+ * true, continue processing to not to send broken packet to the upper
+ * layer.
+ */
+ for (i = rxr->next_to_check;
+ (count < limit) || (discard_multidesc == true);) {
+
struct mbuf *sendmp, *mp;
struct mbuf *newmp;
u32 rsc, ptype;
@@ -1837,7 +1851,7 @@ ixgbe_rxeof(struct ix_queue *que)
if ((staterr & IXGBE_RXD_STAT_DD) == 0)
break;
- count--;
+ count++;
sendmp = NULL;
nbuf = NULL;
rsc = 0;
@@ -1858,17 +1872,37 @@ ixgbe_rxeof(struct ix_queue *que)
#endif
rxr->rx_discarded.ev_count++;
ixgbe_rx_discard(rxr, i);
+ discard_multidesc = false;
goto next_desc;
}
/* pre-alloc new mbuf */
- newmp = ixgbe_getjcl(&rxr->jcl_head, M_NOWAIT, MT_DATA, M_PKTHDR,
- rxr->mbuf_sz);
+ if (!discard_multidesc)
+ newmp = ixgbe_getjcl(&rxr->jcl_head, M_NOWAIT, MT_DATA,
+ M_PKTHDR, rxr->mbuf_sz);
+ else
+ newmp = NULL;
if (newmp == NULL) {
rxr->rx_discarded.ev_count++;
- ixgbe_rx_discard(rxr, i);
+ /*
+ * Descriptor initialization is already done by the
+ * above code (cur->wb.upper.status_error = 0).
+ * So, we can reuse current rbuf->buf for new packet.
+ *
+ * Rewrite the buffer addr, see comment in
+ * ixgbe_rx_discard().
+ */
+ cur->read.pkt_addr = rbuf->addr;
+ m_freem(rbuf->fmp);
+ rbuf->fmp = NULL;
+ if (!eop) {
+ /* Discard the entire packet. */
+ discard_multidesc = true;
+ } else
+ discard_multidesc = false;
goto next_desc;
}
+ discard_multidesc = false;
bus_dmamap_sync(rxr->ptag->dt_dmat, rbuf->pmap, 0,
rbuf->buf->m_pkthdr.len, BUS_DMASYNC_POSTREAD);
