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, 83 insertions, 46 deletions

diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index e802220..8c175f8 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -35,14 +35,20 @@
 
 #include <netinet/tcp.h>
 
-struct vnet;
+#ifdef _KERNEL
+#include <net/vnet.h>
 
 /*
  * Kernel variables for tcp.
  */
-#ifdef VIMAGE_GLOBALS
-extern int	tcp_do_rfc1323;
-#endif
+VNET_DECLARE(int, tcp_do_rfc1323);
+VNET_DECLARE(int, tcp_reass_qsize);
+VNET_DECLARE(struct uma_zone *, tcp_reass_zone);
+#define	V_tcp_do_rfc1323	VNET_GET(tcp_do_rfc1323)
+#define	V_tcp_reass_qsize	VNET_GET(tcp_reass_qsize)
+#define	V_tcp_reass_zone	VNET_GET(tcp_reass_zone)
+
+#endif /* _KERNEL */
 
 /* TCP segment queue entry */
 struct tseg_qent {
@@ -52,10 +58,6 @@ struct tseg_qent {
 	struct	mbuf	*tqe_m;		/* mbuf contains packet */
 };
 LIST_HEAD(tsegqe_head, tseg_qent);
-#ifdef VIMAGE_GLOBALS
-extern int	tcp_reass_qsize;
-#endif
-extern struct uma_zone *tcp_reass_zone;
 
 struct sackblk {
 	tcp_seq start;		/* start seq no. of sack block */
@@ -538,44 +540,79 @@ MALLOC_DECLARE(M_TCPLOG);
 
 extern	int tcp_log_in_vain;
 
-#ifdef VIMAGE_GLOBALS
-extern	struct inpcbhead tcb;		/* head of queue of active tcpcb's */
-extern	struct inpcbinfo tcbinfo;
-extern	struct tcpstat tcpstat;	/* tcp statistics */
-extern	int tcp_mssdflt;	/* XXX */
-extern	int tcp_minmss;
-extern	int tcp_delack_enabled;
-extern	int tcp_do_newreno;
-extern	int path_mtu_discovery;
-extern	int ss_fltsz;
-extern	int ss_fltsz_local;
-
-extern	int blackhole;
-extern	int drop_synfin;
-extern	int tcp_do_rfc3042;
-extern	int tcp_do_rfc3390;
-extern	int tcp_insecure_rst;
-extern	int tcp_do_autorcvbuf;
-extern	int tcp_autorcvbuf_inc;
-extern	int tcp_autorcvbuf_max;
-extern	int tcp_do_rfc3465;
-extern	int tcp_abc_l_var;
-
-extern	int tcp_do_tso;
-extern	int tcp_do_autosndbuf;
-extern	int tcp_autosndbuf_inc;
-extern	int tcp_autosndbuf_max;
-
-extern	int nolocaltimewait;
-
-extern	int tcp_do_sack;		/* SACK enabled/disabled */
-extern	int tcp_sack_maxholes;
-extern	int tcp_sack_globalmaxholes;
-extern	int tcp_sack_globalholes;
-extern	int tcp_sc_rst_sock_fail;	/* RST on sock alloc failure */
-extern	int tcp_do_ecn;			/* TCP ECN enabled/disabled */
-extern	int tcp_ecn_maxretries;
-#endif /* VIMAGE_GLOBALS */
+VNET_DECLARE(struct inpcbhead, tcb);		/* queue of active tcpcb's */
+VNET_DECLARE(struct inpcbinfo, tcbinfo);
+VNET_DECLARE(struct tcpstat, tcpstat);		/* tcp statistics */
+VNET_DECLARE(int, tcp_mssdflt);	/* XXX */
+VNET_DECLARE(int, tcp_minmss);
+VNET_DECLARE(int, tcp_delack_enabled);
+VNET_DECLARE(int, tcp_do_newreno);
+VNET_DECLARE(int, path_mtu_discovery);
+VNET_DECLARE(int, ss_fltsz);
+VNET_DECLARE(int, ss_fltsz_local);
+
+#define	V_tcb			VNET_GET(tcb)
+#define	V_tcbinfo		VNET_GET(tcbinfo)
+#define	V_tcpstat		VNET_GET(tcpstat)
+#define	V_tcp_mssdflt		VNET_GET(tcp_mssdflt)
+#define	V_tcp_minmss		VNET_GET(tcp_minmss)
+#define	V_tcp_delack_enabled	VNET_GET(tcp_delack_enabled)
+#define	V_tcp_do_newreno	VNET_GET(tcp_do_newreno)
+#define	V_path_mtu_discovery	VNET_GET(path_mtu_discovery)
+#define	V_ss_fltsz		VNET_GET(ss_fltsz)
+#define	V_ss_fltsz_local	VNET_GET(ss_fltsz_local)
+
+VNET_DECLARE(int, blackhole);
+VNET_DECLARE(int, drop_synfin);
+VNET_DECLARE(int, tcp_do_rfc3042);
+VNET_DECLARE(int, tcp_do_rfc3390);
+VNET_DECLARE(int, tcp_insecure_rst);
+VNET_DECLARE(int, tcp_do_autorcvbuf);
+VNET_DECLARE(int, tcp_autorcvbuf_inc);
+VNET_DECLARE(int, tcp_autorcvbuf_max);
+VNET_DECLARE(int, tcp_do_rfc3465);
+VNET_DECLARE(int, tcp_abc_l_var);
+
+#define	V_blackhole		VNET_GET(blackhole)
+#define	V_drop_synfin		VNET_GET(drop_synfin)
+#define	V_tcp_do_rfc3042	VNET_GET(tcp_do_rfc3042)
+#define	V_tcp_do_rfc3390	VNET_GET(tcp_do_rfc3390)
+#define	V_tcp_insecure_rst	VNET_GET(tcp_insecure_rst)
+#define	V_tcp_do_autorcvbuf	VNET_GET(tcp_do_autorcvbuf)
+#define	V_tcp_autorcvbuf_inc	VNET_GET(tcp_autorcvbuf_inc)
+#define	V_tcp_autorcvbuf_max	VNET_GET(tcp_autorcvbuf_max)
+#define	V_tcp_do_rfc3465	VNET_GET(tcp_do_rfc3465)
+#define	V_tcp_abc_l_var		VNET_GET(tcp_abc_l_var)
+
+VNET_DECLARE(int, tcp_do_tso);
+VNET_DECLARE(int, tcp_do_autosndbuf);
+VNET_DECLARE(int, tcp_autosndbuf_inc);
+VNET_DECLARE(int, tcp_autosndbuf_max);
+
+#define	V_tcp_do_tso		VNET_GET(tcp_do_tso)
+#define	V_tcp_do_autosndbuf	VNET_GET(tcp_do_autosndbuf)
+#define	V_tcp_autosndbuf_inc	VNET_GET(tcp_autosndbuf_inc)
+#define	V_tcp_autosndbuf_max	VNET_GET(tcp_autosndbuf_max)
+
+VNET_DECLARE(int, nolocaltimewait);
+
+#define	V_nolocaltimewait	VNET_GET(nolocaltimewait)
+
+VNET_DECLARE(int, tcp_do_sack);			/* SACK enabled/disabled */
+VNET_DECLARE(int, tcp_sack_maxholes);
+VNET_DECLARE(int, tcp_sack_globalmaxholes);
+VNET_DECLARE(int, tcp_sack_globalholes);
+VNET_DECLARE(int, tcp_sc_rst_sock_fail);	/* RST on sock alloc failure */
+VNET_DECLARE(int, tcp_do_ecn);			/* TCP ECN enabled/disabled */
+VNET_DECLARE(int, tcp_ecn_maxretries);
+
+#define	V_tcp_do_sack		VNET_GET(tcp_do_sack)
+#define	V_tcp_sack_maxholes	VNET_GET(tcp_sack_maxholes)
+#define	V_tcp_sack_globalmaxholes	VNET_GET(tcp_sack_globalmaxholes)
+#define	V_tcp_sack_globalholes	VNET_GET(tcp_sack_globalholes)
+#define	V_tcp_sc_rst_sock_fail	VNET_GET(tcp_sc_rst_sock_fail)
+#define	V_tcp_do_ecn		VNET_GET(tcp_do_ecn)
+#define	V_tcp_ecn_maxretries	VNET_GET(tcp_ecn_maxretries)
 
 int	 tcp_addoptions(struct tcpopt *, u_char *);
 struct tcpcb *