git: dd6ab49a9aeb - main - netmap: add a tunable for the maximum number of VALE switches

The branch main has been updated by vmaffione:

URL: https://cgit.FreeBSD.org/src/commit/?id=dd6ab49a9aebb5fbb85973d9a859d24daa5e2165

commit dd6ab49a9aebb5fbb85973d9a859d24daa5e2165
Author:     Vincenzo Maffione <vmaffione@FreeBSD.org>
AuthorDate: 2022-03-06 17:28:44 +0000
Commit:     Vincenzo Maffione <vmaffione@FreeBSD.org>
CommitDate: 2022-03-06 17:29:44 +0000

    netmap: add a tunable for the maximum number of VALE switches
    
    The new dev.netmap.max_bridges sysctl tunable can be set in
    loader.conf(5) to change the default maximum number of VALE
    switches that can be created. Current defaults is 8.
    
    MFC after:      2 weeks
---
 share/man/man4/netmap.4      |  7 ++++++-
 share/man/man4/vale.4        |  5 +++--
 sys/dev/netmap/netmap_bdg.c  |  4 ++--
 sys/dev/netmap/netmap_kern.h |  4 +++-
 sys/dev/netmap/netmap_vale.c | 13 +++++++++----
 5 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/share/man/man4/netmap.4 b/share/man/man4/netmap.4
index 46a2f53b9b1f..535b2dfdfb4e 100644
--- a/share/man/man4/netmap.4
+++ b/share/man/man4/netmap.4
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 3, 2020
+.Dd March 6, 2022
 .Dt NETMAP 4
 .Os
 .Sh NAME
@@ -933,6 +933,11 @@ Batch size used when moving packets across a
 switch.
 Values above 64 generally guarantee good
 performance.
+.It Va dev.netmap.max_bridges: 8
+Max number of
+.Nm VALE
+switches that can be created. This tunable can be specified
+at loader time.
 .It Va dev.netmap.ptnet_vnet_hdr: 1
 Allow ptnet devices to use virtio-net headers
 .El
diff --git a/share/man/man4/vale.4 b/share/man/man4/vale.4
index a28114470a6e..f805b1b4031b 100644
--- a/share/man/man4/vale.4
+++ b/share/man/man4/vale.4
@@ -28,7 +28,7 @@
 .\" $FreeBSD$
 .\" $Id: $
 .\"
-.Dd February 6, 2020
+.Dd March 6, 2022
 .Dt VALE 4
 .Os
 .Sh NAME
@@ -77,7 +77,8 @@ See
 for details on the API.
 .Ss LIMITS
 .Nm
-currently supports up to 8 switches, with 254 ports per switch.
+currently supports up to 254 ports per switch. The maximum
+number of switches is provided by the max_bridges sysctl variable.
 .Sh SYSCTL VARIABLES
 See
 .Xr netmap 4
diff --git a/sys/dev/netmap/netmap_bdg.c b/sys/dev/netmap/netmap_bdg.c
index 103a3b00762e..1d49a97eec12 100644
--- a/sys/dev/netmap/netmap_bdg.c
+++ b/sys/dev/netmap/netmap_bdg.c
@@ -1828,7 +1828,7 @@ netmap_init_bridges(void)
 #ifdef CONFIG_NET_NS
 	return netmap_bns_register();
 #else
-	nm_bridges = netmap_init_bridges2(NM_BRIDGES);
+	nm_bridges = netmap_init_bridges2(vale_max_bridges);
 	if (nm_bridges == NULL)
 		return ENOMEM;
 	return 0;
@@ -1841,6 +1841,6 @@ netmap_uninit_bridges(void)
 #ifdef CONFIG_NET_NS
 	netmap_bns_unregister();
 #else
-	netmap_uninit_bridges2(nm_bridges, NM_BRIDGES);
+	netmap_uninit_bridges2(nm_bridges, vale_max_bridges);
 #endif
 }
diff --git a/sys/dev/netmap/netmap_kern.h b/sys/dev/netmap/netmap_kern.h
index 5d8957241c21..f8d824f08ebb 100644
--- a/sys/dev/netmap/netmap_kern.h
+++ b/sys/dev/netmap/netmap_kern.h
@@ -1559,6 +1559,8 @@ int netmap_get_vale_na(struct nmreq_header *hdr, struct netmap_adapter **na,
 void *netmap_vale_create(const char *bdg_name, int *return_status);
 int netmap_vale_destroy(const char *bdg_name, void *auth_token);
 
+extern unsigned int vale_max_bridges;
+
 #else /* !WITH_VALE */
 #define netmap_bdg_learning(_1, _2, _3, _4)	0
 #define	netmap_get_vale_na(_1, _2, _3, _4)	0
@@ -1606,7 +1608,7 @@ extern struct nm_bridge *nm_bridges;
 #define netmap_bns_get()
 #define netmap_bns_put(_1)
 #define netmap_bns_getbridges(b, n) \
-	do { *b = nm_bridges; *n = NM_BRIDGES; } while (0)
+	do { *b = nm_bridges; *n = vale_max_bridges; } while (0)
 #endif
 
 /* Various prototypes */
diff --git a/sys/dev/netmap/netmap_vale.c b/sys/dev/netmap/netmap_vale.c
index aac4cfe6736a..7813984ad295 100644
--- a/sys/dev/netmap/netmap_vale.c
+++ b/sys/dev/netmap/netmap_vale.c
@@ -84,10 +84,9 @@ __FBSDID("$FreeBSD$");
 
 /*
  * system parameters (most of them in netmap_kern.h)
- * NM_BDG_NAME	prefix for switch port names, default "vale"
+ * NM_BDG_NAME		prefix for switch port names, default "vale"
  * NM_BDG_MAXPORTS	number of ports
- * NM_BRIDGES	max number of switches in the system.
- *	XXX should become a sysctl or tunable
+ * NM_BRIDGES		max number of switches in the system.
  *
  * Switch ports are named valeX:Y where X is the switch name and Y
  * is the port. If Y matches a physical interface name, the port is
@@ -115,10 +114,16 @@ __FBSDID("$FreeBSD$");
  * last packet in the block may overflow the size.
  */
 static int bridge_batch = NM_BDG_BATCH; /* bridge batch size */
+
+/* Max number of vale bridges (loader tunable). */
+unsigned int vale_max_bridges = NM_BRIDGES;
+
 SYSBEGIN(vars_vale);
 SYSCTL_DECL(_dev_netmap);
 SYSCTL_INT(_dev_netmap, OID_AUTO, bridge_batch, CTLFLAG_RW, &bridge_batch, 0,
 		"Max batch size to be used in the bridge");
+SYSCTL_UINT(_dev_netmap, OID_AUTO, max_bridges, CTLFLAG_RDTUN, &vale_max_bridges, 0,
+		"Max number of vale bridges");
 SYSEND;
 
 static int netmap_vale_vp_create(struct nmreq_header *hdr, struct ifnet *,
@@ -366,7 +371,7 @@ netmap_vale_list(struct nmreq_header *hdr)
 		j = req->nr_port_idx;
 
 		NMG_LOCK();
-		for (error = ENOENT; i < NM_BRIDGES; i++) {
+		for (error = ENOENT; i < vale_max_bridges; i++) {
 			b = bridges + i;
 			for ( ; j < NM_BDG_MAXPORTS; j++) {
 				if (b->bdg_ports[j] == NULL)