Before this patch the kernel chose the lowest available number for
newly created datapath ports. This patch moves the port number
choosing responsibility to user space, and implements a least
recently used port number queue in an attempt to avoid reuse.
Bug #2140.
---
lib/dpif-linux.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 60 insertions(+), 5 deletions(-)
diff --git a/lib/dpif-linux.c b/lib/dpif-linux.c
index b5590c4..464ac88 100644
--- a/lib/dpif-linux.c
+++ b/lib/dpif-linux.c
@@ -52,6 +52,10 @@
VLOG_DEFINE_THIS_MODULE(dpif_linux);
+enum { LRU_MAX_PORTS = 1024 };
+enum { LRU_MASK = LRU_MAX_PORTS - 1};
+BUILD_ASSERT_DECL(IS_POW2(LRU_MAX_PORTS));
+
struct dpif_linux_dp {
/* Generic Netlink header. */
uint8_t cmd;
@@ -128,6 +132,11 @@ struct dpif_linux {
struct sset changed_ports; /* Ports that have changed. */
struct rtnetlink_notifier port_notifier;
bool change_error;
+
+ /* Queue of unused ports. */
+ uint16_t lru_ports[LRU_MAX_PORTS];
+ size_t lru_head;
+ size_t lru_tail;
};
static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(9999, 5);
@@ -158,6 +167,36 @@ dpif_linux_cast(const struct dpif *dpif)
return CONTAINER_OF(dpif, struct dpif_linux, dpif);
}
+static void
+dpif_linux_push_port(struct dpif_linux *dp, uint16_t port)
+{
+ size_t i;
+
+ if (dp->lru_head - dp->lru_tail >= LRU_MAX_PORTS) {
+ return;
+ }
+
+ /* XXX: Replace this loop with a bitmap indicating which ports are in the
+ * queue. */
+ for (i = dp->lru_tail; i != dp->lru_head; i++) {
+ if (dp->lru_ports[i & LRU_MASK] == port) {
+ return;
+ }
+ }
+
+ dp->lru_ports[dp->lru_head++ & LRU_MASK] = port;
+}
+
+static uint32_t
+dpif_linux_pop_port(struct dpif_linux *dp)
+{
+ if (dp->lru_head == dp->lru_tail) {
+ return UINT32_MAX;
+ }
+
+ return dp->lru_ports[dp->lru_tail++ & LRU_MASK];
+}
+
static int
dpif_linux_enumerate(struct sset *all_dps)
{
@@ -235,6 +274,10 @@ open_dpif(const struct dpif_linux_dp *dp, struct dpif
**dpifp)
dpif->change_error = false;
*dpifp = &dpif->dpif;
+ dpif->lru_head = dpif->lru_tail = 0;
+ for (i = 1; i < LRU_MAX_PORTS; i++) {
+ dpif_linux_push_port(dpif, i);
+ }
return 0;
error_free:
@@ -336,11 +379,17 @@ dpif_linux_port_add(struct dpif *dpif_, struct netdev
*netdev,
request.options_len = options->size;
}
- error = dpif_linux_vport_transact(&request, &reply, &buf);
- if (!error) {
- *port_nop = reply.port_no;
+ /* Loop until we find a port that isn't used. */
+ do {
+ request.port_no = dpif_linux_pop_port(dpif);
+ error = dpif_linux_vport_transact(&request, &reply, &buf);
+
+ if (!error) {
+ *port_nop = reply.port_no;
+ }
ofpbuf_delete(buf);
- }
+ } while (request.port_no != UINT32_MAX
+ && (error == EBUSY || error == EFBIG));
return error;
}
@@ -350,12 +399,18 @@ dpif_linux_port_del(struct dpif *dpif_, uint16_t port_no)
{
struct dpif_linux *dpif = dpif_linux_cast(dpif_);
struct dpif_linux_vport vport;
+ int error;
dpif_linux_vport_init(&vport);
vport.cmd = ODP_VPORT_CMD_DEL;
vport.dp_ifindex = dpif->dp_ifindex;
vport.port_no = port_no;
- return dpif_linux_vport_transact(&vport, NULL, NULL);
+ error = dpif_linux_vport_transact(&vport, NULL, NULL);
+
+ if (!error) {
+ dpif_linux_push_port(dpif, port_no);
+ }
+ return error;
}
static int
--
1.7.4.2
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