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[src/trunk]: src/sys/arch/xen/xen Cleanup the TX path:
details: https://anonhg.NetBSD.org/src/rev/35673c1a57e5
branches: trunk
changeset: 446860:35673c1a57e5
user: bouyer <bouyer%NetBSD.org@localhost>
date: Sun Dec 23 12:09:45 2018 +0000
description:
Cleanup the TX path:
- split in sub-functions
- ratelimit printf for mbuf allocation failure
- don't loop forever on mbuf allocation failure
diffstat:
sys/arch/xen/xen/xennetback_xenbus.c | 136 ++++++++++++++++++++--------------
1 files changed, 79 insertions(+), 57 deletions(-)
diffs (196 lines):
diff -r ce24e6da0c2b -r 35673c1a57e5 sys/arch/xen/xen/xennetback_xenbus.c
--- a/sys/arch/xen/xen/xennetback_xenbus.c Sun Dec 23 11:45:39 2018 +0000
+++ b/sys/arch/xen/xen/xennetback_xenbus.c Sun Dec 23 12:09:45 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: xennetback_xenbus.c,v 1.71 2018/10/26 05:33:21 cherry Exp $ */
+/* $NetBSD: xennetback_xenbus.c,v 1.72 2018/12/23 12:09:45 bouyer Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -25,7 +25,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.71 2018/10/26 05:33:21 cherry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xennetback_xenbus.c,v 1.72 2018/12/23 12:09:45 bouyer Exp $");
#include "opt_xen.h"
@@ -1215,6 +1215,64 @@
splx(s);
}
+/*
+ * sighly different from m_dup(); for some reason m_dup() can return
+ * a chain where the data area can cross a page boundary.
+ * This doesn't happens with the function below.
+ */
+static struct mbuf *
+xennetback_copymbuf(struct mbuf *m)
+{
+ struct mbuf *new_m;
+
+ MGETHDR(new_m, M_DONTWAIT, MT_DATA);
+ if (__predict_false(new_m == NULL)) {
+ return NULL;
+ }
+ if (m->m_pkthdr.len > MHLEN) {
+ MCLGET(new_m, M_DONTWAIT);
+ if (__predict_false(
+ (new_m->m_flags & M_EXT) == 0)) {
+ m_freem(new_m);
+ return NULL;
+ }
+ }
+ m_copydata(m, 0, m->m_pkthdr.len,
+ mtod(new_m, void *));
+ new_m->m_len = new_m->m_pkthdr.len =
+ m->m_pkthdr.len;
+ return new_m;
+}
+
+/* return physical page address and offset of data area of an mbuf */
+static void
+xennetback_mbuf_addr(struct mbuf *m, paddr_t *xmit_pa, int *offset)
+{
+ switch (m->m_flags & (M_EXT|M_EXT_CLUSTER)) {
+ case M_EXT|M_EXT_CLUSTER:
+ KASSERT(m->m_ext.ext_paddr != M_PADDR_INVALID);
+ *xmit_pa = m->m_ext.ext_paddr;
+ *offset = m->m_data - m->m_ext.ext_buf;
+ break;
+ case 0:
+ KASSERT(m->m_paddr != M_PADDR_INVALID);
+ *xmit_pa = m->m_paddr;
+ *offset = M_BUFOFFSET(m) +
+ (m->m_data - M_BUFADDR(m));
+ break;
+ default:
+ if (__predict_false(
+ !pmap_extract(pmap_kernel(),
+ (vaddr_t)m->m_data, xmit_pa))) {
+ panic("xennet_start: no pa");
+ }
+ *offset = 0;
+ break;
+ }
+ *offset += (*xmit_pa & ~PG_FRAME);
+ *xmit_pa = (*xmit_pa & PG_FRAME);
+}
+
static void
xennetback_ifsoftstart_copy(void *arg)
{
@@ -1230,6 +1288,7 @@
int do_event = 0;
gnttab_copy_t *gop;
int id, offset;
+ bool abort;
XENPRINTF(("xennetback_ifsoftstart_copy "));
int s = splnet();
@@ -1246,6 +1305,7 @@
xen_rmb();
gop = xstart_gop_copy;
+ abort = false;
for (i = 0; !IFQ_IS_EMPTY(&ifp->if_snd);) {
XENPRINTF(("have a packet\n"));
IFQ_POLL(&ifp->if_snd, m);
@@ -1261,69 +1321,30 @@
"0x%x\n",
req_prod, xneti->xni_rxring.req_cons,
resp_prod));
- ifp->if_timer = 1;
+ abort = true;
break;
}
if (__predict_false(i == NB_XMIT_PAGES_BATCH))
break; /* we filled the array */
- switch (m->m_flags & (M_EXT|M_EXT_CLUSTER)) {
- case M_EXT|M_EXT_CLUSTER:
- KASSERT(m->m_ext.ext_paddr != M_PADDR_INVALID);
- xmit_pa = m->m_ext.ext_paddr;
- offset = m->m_data - m->m_ext.ext_buf;
- break;
- case 0:
- KASSERT(m->m_paddr != M_PADDR_INVALID);
- xmit_pa = m->m_paddr;
- offset = M_BUFOFFSET(m) +
- (m->m_data - M_BUFADDR(m));
- break;
- default:
- if (__predict_false(
- !pmap_extract(pmap_kernel(),
- (vaddr_t)m->m_data, &xmit_pa))) {
- panic("xennet_start: no pa");
- }
- offset = 0;
- break;
- }
- offset += (xmit_pa & ~PG_FRAME);
- xmit_pa = (xmit_pa & PG_FRAME);
+
+ xennetback_mbuf_addr(m, &xmit_pa, &offset);
if (m->m_pkthdr.len != m->m_len ||
(offset + m->m_pkthdr.len) > PAGE_SIZE) {
- MGETHDR(new_m, M_DONTWAIT, MT_DATA);
+ new_m = xennetback_copymbuf(m);
if (__predict_false(new_m == NULL)) {
- printf("%s: cannot allocate new mbuf\n",
- ifp->if_xname);
+ static struct timeval lasttime;
+ if (ratecheck(&lasttime, &xni_pool_errintvl))
+ printf("%s: cannot allocate new mbuf\n",
+ ifp->if_xname);
+ abort = 1;
break;
+ } else {
+ IFQ_DEQUEUE(&ifp->if_snd, m);
+ m_freem(m);
+ m = new_m;
+ xennetback_mbuf_addr(m,
+ &xmit_pa, &offset);
}
- if (m->m_pkthdr.len > MHLEN) {
- MCLGET(new_m, M_DONTWAIT);
- if (__predict_false(
- (new_m->m_flags & M_EXT) == 0)) {
- XENPRINTF((
- "%s: no mbuf cluster\n",
- ifp->if_xname));
- m_freem(new_m);
- break;
- }
- xmit_pa = new_m->m_ext.ext_paddr;
- offset = new_m->m_data -
- new_m->m_ext.ext_buf;
- } else {
- xmit_pa = new_m->m_paddr;
- offset = M_BUFOFFSET(new_m) +
- (new_m->m_data - M_BUFADDR(new_m));
- }
- offset += (xmit_pa & ~PG_FRAME);
- xmit_pa = (xmit_pa & PG_FRAME);
- m_copydata(m, 0, m->m_pkthdr.len,
- mtod(new_m, void *));
- new_m->m_len = new_m->m_pkthdr.len =
- m->m_pkthdr.len;
- IFQ_DEQUEUE(&ifp->if_snd, m);
- m_freem(m);
- m = new_m;
} else {
IFQ_DEQUEUE(&ifp->if_snd, m);
}
@@ -1421,9 +1442,10 @@
* here, as the frontend doesn't notify when adding
* requests anyway
*/
- if (__predict_false(
+ if (__predict_false(abort ||
!RING_HAS_UNCONSUMED_REQUESTS(&xneti->xni_rxring))) {
/* ring full */
+ ifp->if_timer = 1;
break;
}
}
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