[v2,2/2] netvsc: resize event buffer as needed
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Commit Message
The event buffer was changed to be a fixed size value, but it
is not large enough for a forwarding stress test.
This version of event buffer code uses malloc/realloc to size
the event buffer as needed. Malloc is preferred over rte_malloc
because the event buffer does not need to be used for DMA
and huge page is a limited resource.
Fixes: 530af95a7849 ("bus/vmbus: avoid signalling host on read")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
---
drivers/net/netvsc/hn_rxtx.c | 50 ++++++++++++++++++++++++++----------
drivers/net/netvsc/hn_var.h | 2 +-
2 files changed, 37 insertions(+), 15 deletions(-)
Comments
On Mon, 13 Aug 2018 08:51:08 -0700
Stephen Hemminger <stephen@networkplumber.org> wrote:
> The event buffer was changed to be a fixed size value, but it
> is not large enough for a forwarding stress test.
>
> This version of event buffer code uses malloc/realloc to size
> the event buffer as needed. Malloc is preferred over rte_malloc
> because the event buffer does not need to be used for DMA
> and huge page is a limited resource.
>
> Fixes: 530af95a7849 ("bus/vmbus: avoid signalling host on read")
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Self NAK. This won't work when secondary process needs the buffer.
@@ -10,6 +10,7 @@
#include <errno.h>
#include <unistd.h>
#include <strings.h>
+#include <malloc.h>
#include <rte_ethdev.h>
#include <rte_memcpy.h>
@@ -718,16 +719,22 @@ struct hn_rx_queue *hn_rx_queue_alloc(struct hn_data *hv,
{
struct hn_rx_queue *rxq;
- rxq = rte_zmalloc_socket("HN_RXQ",
- sizeof(*rxq) + HN_RXQ_EVENT_DEFAULT,
+ rxq = rte_zmalloc_socket("HN_RXQ", sizeof(*rxq),
RTE_CACHE_LINE_SIZE, socket_id);
- if (rxq) {
- rxq->hv = hv;
- rxq->chan = hv->channels[queue_id];
- rte_spinlock_init(&rxq->ring_lock);
- rxq->port_id = hv->port_id;
- rxq->queue_id = queue_id;
+ if (!rxq)
+ return NULL;
+
+ rxq->hv = hv;
+ rxq->chan = hv->channels[queue_id];
+ rte_spinlock_init(&rxq->ring_lock);
+ rxq->port_id = hv->port_id;
+ rxq->queue_id = queue_id;
+ rxq->event_buf = malloc(HN_RXQ_EVENT_DEFAULT);
+ if (!rxq->event_buf) {
+ free(rxq);
+ return NULL;
}
+
return rxq;
}
@@ -776,6 +783,7 @@ hn_dev_rx_queue_setup(struct rte_eth_dev *dev,
fail:
rte_ring_free(rxq->rx_ring);
+ free(rxq->event_buf);
rte_free(rxq);
return -ENOMEM;
}
@@ -794,8 +802,10 @@ hn_dev_rx_queue_release(void *arg)
rxq->rx_ring = NULL;
rxq->mb_pool = NULL;
- if (rxq != rxq->hv->primary)
+ if (rxq != rxq->hv->primary) {
+ free(rxq->event_buf);
rte_free(rxq);
+ }
}
void
@@ -850,19 +860,31 @@ void hn_process_events(struct hn_data *hv, uint16_t queue_id)
for (;;) {
const struct vmbus_chanpkt_hdr *pkt;
- uint32_t len = HN_RXQ_EVENT_DEFAULT;
+ uint32_t len = malloc_usable_size(rxq->event_buf);
const void *data;
+retry:
ret = rte_vmbus_chan_recv_raw(rxq->chan, rxq->event_buf, &len);
if (ret == -EAGAIN)
break; /* ring is empty */
- else if (ret == -ENOBUFS)
- rte_exit(EXIT_FAILURE, "event buffer not big enough (%u < %u)",
- HN_RXQ_EVENT_DEFAULT, len);
- else if (ret <= 0)
+ if (unlikely(ret == -ENOBUFS)) {
+ /* event buffer not large enough to read ring */
+
+ PMD_DRV_LOG(DEBUG,
+ "event buffer expansion (need %u)", len);
+ rxq->event_buf = realloc(rxq->event_buf, len);
+ if (rxq->event_buf)
+ goto retry;
+ /* out of memory, no more events now */
+ break;
+ }
+
+ if (unlikely(ret <= 0)) {
+ /* This indicates a failure to communicate (or worse) */
rte_exit(EXIT_FAILURE,
"vmbus ring buffer error: %d", ret);
+ }
bytes_read += ret;
pkt = (const struct vmbus_chanpkt_hdr *)rxq->event_buf;
@@ -77,7 +77,7 @@ struct hn_rx_queue {
struct hn_stats stats;
uint64_t ring_full;
- uint8_t event_buf[];
+ void *event_buf;
};