Build on Jeff Roberson's linker-set based dynamic per-CPU allocator

(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)

1 files changed, 18 insertions, 22 deletions

diff --git a/sys/netinet/in_rmx.c b/sys/netinet/in_rmx.c
index feaa2f9..d391871 100644
--- a/sys/netinet/in_rmx.c
+++ b/sys/netinet/in_rmx.c
@@ -59,7 +59,6 @@ __FBSDID("$FreeBSD$");
 #include <netinet/in.h>
 #include <netinet/in_var.h>
 #include <netinet/ip_var.h>
-#include <netinet/vinet.h>
 
 extern int	in_inithead(void **head, int off);
 #ifdef VIMAGE
@@ -132,22 +131,24 @@ in_matroute(void *v_arg, struct radix_node_head *head)
 	return rn;
 }
 
-#ifdef VIMAGE_GLOBALS
-static int rtq_reallyold;
-static int rtq_minreallyold;
-static int rtq_toomany;
-#endif
+static VNET_DEFINE(int, rtq_reallyold);
+static VNET_DEFINE(int, rtq_minreallyold);
+static VNET_DEFINE(int, rtq_toomany);
+
+#define	V_rtq_reallyold		VNET_GET(rtq_reallyold)
+#define	V_rtq_minreallyold	VNET_GET(rtq_minreallyold)
+#define	V_rtq_toomany		VNET_GET(rtq_toomany)
 
-SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_RTEXPIRE, rtexpire,
-    CTLFLAG_RW, rtq_reallyold, 0,
+SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
+    &VNET_NAME(rtq_reallyold), 0,
     "Default expiration time on dynamically learned routes");
 
-SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_RTMINEXPIRE,
-    rtminexpire, CTLFLAG_RW, rtq_minreallyold, 0,
+SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
+    &VNET_NAME(rtq_minreallyold), 0,
     "Minimum time to attempt to hold onto dynamically learned routes");
 
-SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_RTMAXCACHE,
-    rtmaxcache, CTLFLAG_RW, rtq_toomany, 0,
+SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
+    &VNET_NAME(rtq_toomany), 0,
     "Upper limit on dynamically learned routes");
 
 /*
@@ -157,7 +158,6 @@ SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_ip, IPCTL_RTMAXCACHE,
 static void
 in_clsroute(struct radix_node *rn, struct radix_node_head *head)
 {
-	INIT_VNET_INET(curvnet);
 	struct rtentry *rt = (struct rtentry *)rn;
 
 	RT_LOCK_ASSERT(rt);
@@ -200,7 +200,6 @@ struct rtqk_arg {
 static int
 in_rtqkill(struct radix_node *rn, void *rock)
 {
-	INIT_VNET_INET(curvnet);
 	struct rtqk_arg *ap = rock;
 	struct rtentry *rt = (struct rtentry *)rn;
 	int err;
@@ -240,10 +239,11 @@ in_rtqkill(struct radix_node *rn, void *rock)
 }
 
 #define RTQ_TIMEOUT	60*10	/* run no less than once every ten minutes */
-#ifdef VIMAGE_GLOBALS
-static int rtq_timeout;
-static struct callout rtq_timer;
-#endif
+static VNET_DEFINE(int, rtq_timeout);
+static VNET_DEFINE(struct callout, rtq_timer);
+
+#define	V_rtq_timeout		VNET_GET(rtq_timeout)
+#define	V_rtq_timer		VNET_GET(rtq_timer)
 
 static void in_rtqtimo_one(void *rock);
 
@@ -251,7 +251,6 @@ static void
 in_rtqtimo(void *rock)
 {
 	CURVNET_SET((struct vnet *) rock);
-	INIT_VNET_INET(curvnet);
 	int fibnum;
 	void *newrock;
 	struct timeval atv;
@@ -270,7 +269,6 @@ in_rtqtimo(void *rock)
 static void
 in_rtqtimo_one(void *rock)
 {
-	INIT_VNET_INET(curvnet);
 	struct radix_node_head *rnh = rock;
 	struct rtqk_arg arg;
 	static time_t last_adjusted_timeout = 0;
@@ -348,7 +346,6 @@ static int _in_rt_was_here;
 int
 in_inithead(void **head, int off)
 {
-	INIT_VNET_INET(curvnet);
 	struct radix_node_head *rnh;
 
 	/* XXX MRT
@@ -386,7 +383,6 @@ in_inithead(void **head, int off)
 int
 in_detachhead(void **head, int off)
 {
-	INIT_VNET_INET(curvnet);
 
 	callout_drain(&V_rtq_timer);
 	return (1);