svn commit: r362650 - stable/12/sys/net

Kristof Provost kp at FreeBSD.org
Fri Jun 26 12:11:23 UTC 2020


Author: kp
Date: Fri Jun 26 12:11:22 2020
New Revision: 362650
URL: https://svnweb.freebsd.org/changeset/base/362650

Log:
  MFC r360345:
  
  bridge: epoch-ification
  
  Run the bridge datapath under epoch, rather than under the
  BRIDGE_LOCK().
  
  We still take the BRIDGE_LOCK() whenever we insert or delete items in
  the relevant lists, but we use epoch callbacks to free items so that
  it's safe to iterate the lists without the BRIDGE_LOCK.
  
  Tests on mercat5/6 shows this increases bridge throughput significantly,
  from 3.7Mpps to 18.6Mpps.
  
  MFC after:	The FreeBSD Foundation

Modified:
  stable/12/sys/net/if_bridge.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sys/net/if_bridge.c
==============================================================================
--- stable/12/sys/net/if_bridge.c	Fri Jun 26 10:08:57 2020	(r362649)
+++ stable/12/sys/net/if_bridge.c	Fri Jun 26 12:11:22 2020	(r362650)
@@ -237,6 +237,8 @@ struct bridge_iflist {
 	uint32_t		bif_addrmax;	/* max # of addresses */
 	uint32_t		bif_addrcnt;	/* cur. # of addresses */
 	uint32_t		bif_addrexceeded;/* # of address violations */
+
+	struct epoch_context	bif_epoch_ctx;
 };
 
 /*
@@ -250,6 +252,9 @@ struct bridge_rtnode {
 	uint8_t			brt_flags;	/* address flags */
 	uint8_t			brt_addr[ETHER_ADDR_LEN];
 	uint16_t		brt_vlan;	/* vlan id */
+
+	struct	vnet		*brt_vnet;
+	struct	epoch_context	brt_epoch_ctx;
 };
 #define	brt_ifp			brt_dst->bif_ifp
 
@@ -276,6 +281,8 @@ struct bridge_softc {
 	uint32_t		sc_brtexceeded;	/* # of cache drops */
 	struct ifnet		*sc_ifaddr;	/* member mac copied from */
 	struct ether_addr	sc_defaddr;	/* Default MAC address */
+
+	struct epoch_context	sc_epoch_ctx;
 };
 
 VNET_DEFINE_STATIC(struct mtx, bridge_list_mtx);
@@ -595,6 +602,11 @@ vnet_bridge_uninit(const void *unused __unused)
 	if_clone_detach(V_bridge_cloner);
 	V_bridge_cloner = NULL;
 	BRIDGE_LIST_LOCK_DESTROY();
+
+	/* Before we can destroy the uma zone, because there are callbacks that
+	 * use it. */
+	NET_EPOCH_WAIT();
+
 	uma_zdestroy(V_bridge_rtnode_zone);
 }
 VNET_SYSUNINIT(vnet_bridge_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY,
@@ -757,6 +769,17 @@ bridge_clone_create(struct if_clone *ifc, int unit, ca
 	return (0);
 }
 
+static void
+bridge_clone_destroy_cb(struct epoch_context *ctx)
+{
+	struct bridge_softc *sc;
+
+	sc = __containerof(ctx, struct bridge_softc, sc_epoch_ctx);
+
+	BRIDGE_LOCK_DESTROY(sc);
+	free(sc, M_DEVBUF);
+}
+
 /*
  * bridge_clone_destroy:
  *
@@ -795,8 +818,7 @@ bridge_clone_destroy(struct ifnet *ifp)
 	ether_ifdetach(ifp);
 	if_free(ifp);
 
-	BRIDGE_LOCK_DESTROY(sc);
-	free(sc, M_DEVBUF);
+	epoch_call(net_epoch_preempt, &sc->sc_epoch_ctx, bridge_clone_destroy_cb);
 }
 
 /*
@@ -822,7 +844,10 @@ bridge_ioctl(struct ifnet *ifp, u_long cmd, caddr_t da
 	struct ifdrv *ifd = (struct ifdrv *) data;
 	const struct bridge_control *bc;
 	int error = 0, oldmtu;
+	struct epoch_tracker et;
 
+	NET_EPOCH_ENTER_ET(et);
+
 	switch (cmd) {
 
 	case SIOCADDMULTI:
@@ -943,6 +968,8 @@ bridge_ioctl(struct ifnet *ifp, u_long cmd, caddr_t da
 		break;
 	}
 
+	NET_EPOCH_EXIT_ET(et);
+
 	return (error);
 }
 
@@ -957,6 +984,8 @@ bridge_mutecaps(struct bridge_softc *sc)
 	struct bridge_iflist *bif;
 	int enabled, mask;
 
+	BRIDGE_LOCK_ASSERT(sc);
+
 	/* Initial bitmask of capabilities to test */
 	mask = BRIDGE_IFCAPS_MASK;
 
@@ -1018,7 +1047,7 @@ bridge_lookup_member(struct bridge_softc *sc, const ch
 	struct bridge_iflist *bif;
 	struct ifnet *ifp;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
 
 	CK_LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
 		ifp = bif->bif_ifp;
@@ -1039,7 +1068,7 @@ bridge_lookup_member_if(struct bridge_softc *sc, struc
 {
 	struct bridge_iflist *bif;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
 
 	CK_LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
 		if (bif->bif_ifp == member_ifp)
@@ -1049,6 +1078,16 @@ bridge_lookup_member_if(struct bridge_softc *sc, struc
 	return (NULL);
 }
 
+static void
+bridge_delete_member_cb(struct epoch_context *ctx)
+{
+	struct bridge_iflist *bif;
+
+	bif = __containerof(ctx, struct bridge_iflist, bif_epoch_ctx);
+
+	free(bif, M_DEVBUF);
+}
+
 /*
  * bridge_delete_member:
  *
@@ -1129,7 +1168,9 @@ bridge_delete_member(struct bridge_softc *sc, struct b
 	}
 	bstp_destroy(&bif->bif_stp);	/* prepare to free */
 	BRIDGE_LOCK(sc);
-	free(bif, M_DEVBUF);
+
+	epoch_call(net_epoch_preempt, &bif->bif_epoch_ctx,
+	    bridge_delete_member_cb);
 }
 
 /*
@@ -1146,7 +1187,9 @@ bridge_delete_span(struct bridge_softc *sc, struct bri
 	    ("%s: not a span interface", __func__));
 
 	CK_LIST_REMOVE(bif, bif_next);
-	free(bif, M_DEVBUF);
+
+	epoch_call(net_epoch_preempt, &bif->bif_epoch_ctx,
+	    bridge_delete_member_cb);
 }
 
 static int
@@ -1529,12 +1572,17 @@ bridge_ioctl_saddr(struct bridge_softc *sc, void *arg)
 	struct bridge_iflist *bif;
 	int error;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	bif = bridge_lookup_member(sc, req->ifba_ifsname);
 	if (bif == NULL)
 		return (ENOENT);
 
+	/* bridge_rtupdate() may acquire the lock. */
+	BRIDGE_UNLOCK(sc);
 	error = bridge_rtupdate(sc, req->ifba_dst, req->ifba_vlan, bif, 1,
 	    req->ifba_flags);
+	BRIDGE_LOCK(sc);
 
 	return (error);
 }
@@ -1873,6 +1921,7 @@ bridge_ifdetach(void *arg __unused, struct ifnet *ifp)
 {
 	struct bridge_softc *sc = ifp->if_bridge;
 	struct bridge_iflist *bif;
+	struct epoch_tracker et;
 
 	if (ifp->if_flags & IFF_RENAMING)
 		return;
@@ -1883,6 +1932,7 @@ bridge_ifdetach(void *arg __unused, struct ifnet *ifp)
 		 */
 		return;
 	}
+	NET_EPOCH_ENTER_ET(et);
 	/* Check if the interface is a bridge member */
 	if (sc != NULL) {
 		BRIDGE_LOCK(sc);
@@ -1892,6 +1942,7 @@ bridge_ifdetach(void *arg __unused, struct ifnet *ifp)
 			bridge_delete_member(sc, bif, 1);
 
 		BRIDGE_UNLOCK(sc);
+		NET_EPOCH_EXIT_ET(et);
 		return;
 	}
 
@@ -1908,6 +1959,7 @@ bridge_ifdetach(void *arg __unused, struct ifnet *ifp)
 		BRIDGE_UNLOCK(sc);
 	}
 	BRIDGE_LIST_UNLOCK();
+	NET_EPOCH_EXIT_ET(et);
 }
 
 /*
@@ -2067,6 +2119,8 @@ bridge_output(struct ifnet *ifp, struct mbuf *m, struc
 	struct bridge_softc *sc;
 	uint16_t vlan;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	if (m->m_len < ETHER_HDR_LEN) {
 		m = m_pullup(m, ETHER_HDR_LEN);
 		if (m == NULL)
@@ -2077,8 +2131,6 @@ bridge_output(struct ifnet *ifp, struct mbuf *m, struc
 	sc = ifp->if_bridge;
 	vlan = VLANTAGOF(m);
 
-	BRIDGE_LOCK(sc);
-
 	/*
 	 * If bridge is down, but the original output interface is up,
 	 * go ahead and send out that interface.  Otherwise, the packet
@@ -2100,16 +2152,10 @@ bridge_output(struct ifnet *ifp, struct mbuf *m, struc
 	if (dst_if == NULL) {
 		struct bridge_iflist *bif;
 		struct mbuf *mc;
-		int error = 0, used = 0;
+		int used = 0;
 
 		bridge_span(sc, m);
 
-		BRIDGE_LOCK2REF(sc, error);
-		if (error) {
-			m_freem(m);
-			return (0);
-		}
-
 		CK_LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
 			dst_if = bif->bif_ifp;
 
@@ -2143,7 +2189,6 @@ bridge_output(struct ifnet *ifp, struct mbuf *m, struc
 		}
 		if (used == 0)
 			m_freem(m);
-		BRIDGE_UNREF(sc);
 		return (0);
 	}
 
@@ -2155,11 +2200,9 @@ sendunicast:
 	bridge_span(sc, m);
 	if ((dst_if->if_drv_flags & IFF_DRV_RUNNING) == 0) {
 		m_freem(m);
-		BRIDGE_UNLOCK(sc);
 		return (0);
 	}
 
-	BRIDGE_UNLOCK(sc);
 	bridge_enqueue(sc, dst_if, m);
 	return (0);
 }
@@ -2184,10 +2227,8 @@ bridge_transmit(struct ifnet *ifp, struct mbuf *m)
 
 	eh = mtod(m, struct ether_header *);
 
-	BRIDGE_LOCK(sc);
 	if (((m->m_flags & (M_BCAST|M_MCAST)) == 0) &&
 	    (dst_if = bridge_rtlookup(sc, eh->ether_dhost, 1)) != NULL) {
-		BRIDGE_UNLOCK(sc);
 		error = bridge_enqueue(sc, dst_if, m);
 	} else
 		bridge_broadcast(sc, ifp, m, 0);
@@ -2221,6 +2262,8 @@ bridge_forward(struct bridge_softc *sc, struct bridge_
 	uint8_t *dst;
 	int error;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	src_if = m->m_pkthdr.rcvif;
 	ifp = sc->sc_ifp;
 
@@ -2299,12 +2342,10 @@ bridge_forward(struct bridge_softc *sc, struct bridge_
 	    || PFIL_HOOKED(&V_inet6_pfil_hook)
 #endif
 	    ) {
-		BRIDGE_UNLOCK(sc);
 		if (bridge_pfil(&m, ifp, src_if, PFIL_IN) != 0)
 			return;
 		if (m == NULL)
 			return;
-		BRIDGE_LOCK(sc);
 	}
 
 	if (dst_if == NULL) {
@@ -2332,8 +2373,6 @@ bridge_forward(struct bridge_softc *sc, struct bridge_
 	    dbif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING)
 		goto drop;
 
-	BRIDGE_UNLOCK(sc);
-
 	if (PFIL_HOOKED(&V_inet_pfil_hook)
 #ifdef INET6
 	    || PFIL_HOOKED(&V_inet6_pfil_hook)
@@ -2349,7 +2388,6 @@ bridge_forward(struct bridge_softc *sc, struct bridge_
 	return;
 
 drop:
-	BRIDGE_UNLOCK(sc);
 	m_freem(m);
 }
 
@@ -2370,6 +2408,8 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 	uint16_t vlan;
 	int error;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	if ((sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING) == 0)
 		return (m);
 
@@ -2390,10 +2430,8 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 		m_freem(m);
 		return (NULL);
 	}
-	BRIDGE_LOCK(sc);
 	bif = bridge_lookup_member_if(sc, ifp);
 	if (bif == NULL) {
-		BRIDGE_UNLOCK(sc);
 		return (m);
 	}
 
@@ -2406,13 +2444,11 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 		if (memcmp(eh->ether_dhost, bstp_etheraddr,
 		    ETHER_ADDR_LEN) == 0) {
 			bstp_input(&bif->bif_stp, ifp, m); /* consumes mbuf */
-			BRIDGE_UNLOCK(sc);
 			return (NULL);
 		}
 
 		if ((bif->bif_flags & IFBIF_STP) &&
 		    bif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING) {
-			BRIDGE_UNLOCK(sc);
 			return (m);
 		}
 
@@ -2423,7 +2459,6 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 		 */
 		mc = m_dup(m, M_NOWAIT);
 		if (mc == NULL) {
-			BRIDGE_UNLOCK(sc);
 			return (m);
 		}
 
@@ -2455,7 +2490,6 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 
 	if ((bif->bif_flags & IFBIF_STP) &&
 	    bif->bif_stp.bp_state == BSTP_IFSTATE_DISCARDING) {
-		BRIDGE_UNLOCK(sc);
 		return (m);
 	}
 
@@ -2495,7 +2529,6 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 			     OR_PFIL_HOOKED_INET6)) {			\
 				if (bridge_pfil(&m, NULL, ifp,		\
 				    PFIL_IN) != 0 || m == NULL) {	\
-					BRIDGE_UNLOCK(sc);		\
 					return (NULL);			\
 				}					\
 				eh = mtod(m, struct ether_header *);	\
@@ -2505,13 +2538,11 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 			error = bridge_rtupdate(sc, eh->ether_shost,	\
 			    vlan, bif, 0, IFBAF_DYNAMIC);		\
 			if (error && bif->bif_addrmax) {		\
-				BRIDGE_UNLOCK(sc);			\
 				m_freem(m);				\
 				return (NULL);				\
 			}						\
 		}							\
 		m->m_pkthdr.rcvif = iface;				\
-		BRIDGE_UNLOCK(sc);					\
 		return (m);						\
 	}								\
 									\
@@ -2519,7 +2550,6 @@ bridge_input(struct ifnet *ifp, struct mbuf *m)
 	if (memcmp(IF_LLADDR((iface)), eh->ether_shost, ETHER_ADDR_LEN) == 0 \
 	    OR_CARP_CHECK_WE_ARE_SRC((iface))			\
 	    ) {								\
-		BRIDGE_UNLOCK(sc);					\
 		m_freem(m);						\
 		return (NULL);						\
 	}
@@ -2570,16 +2600,12 @@ bridge_broadcast(struct bridge_softc *sc, struct ifnet
 	struct bridge_iflist *dbif, *sbif;
 	struct mbuf *mc;
 	struct ifnet *dst_if;
-	int error = 0, used = 0, i;
+	int used = 0, i;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	sbif = bridge_lookup_member_if(sc, src_if);
 
-	BRIDGE_LOCK2REF(sc, error);
-	if (error) {
-		m_freem(m);
-		return;
-	}
-
 	/* Filter on the bridge interface before broadcasting */
 	if (runfilt && (PFIL_HOOKED(&V_inet_pfil_hook)
 #ifdef INET6
@@ -2587,9 +2613,9 @@ bridge_broadcast(struct bridge_softc *sc, struct ifnet
 #endif
 	    )) {
 		if (bridge_pfil(&m, sc->sc_ifp, NULL, PFIL_OUT) != 0)
-			goto out;
+			return;
 		if (m == NULL)
-			goto out;
+			return;
 	}
 
 	CK_LIST_FOREACH(dbif, &sc->sc_iflist, bif_next) {
@@ -2652,9 +2678,6 @@ bridge_broadcast(struct bridge_softc *sc, struct ifnet
 	}
 	if (used == 0)
 		m_freem(m);
-
-out:
-	BRIDGE_UNREF(sc);
 }
 
 /*
@@ -2670,6 +2693,8 @@ bridge_span(struct bridge_softc *sc, struct mbuf *m)
 	struct ifnet *dst_if;
 	struct mbuf *mc;
 
+	MPASS(in_epoch(net_epoch_preempt));
+
 	if (CK_LIST_EMPTY(&sc->sc_spanlist))
 		return;
 
@@ -2701,7 +2726,8 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t
 	struct bridge_rtnode *brt;
 	int error;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
+	BRIDGE_UNLOCK_ASSERT(sc);
 
 	/* Check the source address is valid and not multicast. */
 	if (ETHER_IS_MULTICAST(dst) ||
@@ -2718,13 +2744,24 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t
 	 * update it, otherwise create a new one.
 	 */
 	if ((brt = bridge_rtnode_lookup(sc, dst, vlan)) == NULL) {
+		BRIDGE_LOCK(sc);
+
+		/* Check again, now that we have the lock. There could have
+		 * been a race and we only want to insert this once. */
+		if ((brt = bridge_rtnode_lookup(sc, dst, vlan)) != NULL) {
+			BRIDGE_UNLOCK(sc);
+			return (0);
+		}
+
 		if (sc->sc_brtcnt >= sc->sc_brtmax) {
 			sc->sc_brtexceeded++;
+			BRIDGE_UNLOCK(sc);
 			return (ENOSPC);
 		}
 		/* Check per interface address limits (if enabled) */
 		if (bif->bif_addrmax && bif->bif_addrcnt >= bif->bif_addrmax) {
 			bif->bif_addrexceeded++;
+			BRIDGE_UNLOCK(sc);
 			return (ENOSPC);
 		}
 
@@ -2734,8 +2771,11 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t
 		 * address.
 		 */
 		brt = uma_zalloc(V_bridge_rtnode_zone, M_NOWAIT | M_ZERO);
-		if (brt == NULL)
+		if (brt == NULL) {
+			BRIDGE_UNLOCK(sc);
 			return (ENOMEM);
+		}
+		brt->brt_vnet = curvnet;
 
 		if (bif->bif_flags & IFBIF_STICKY)
 			brt->brt_flags = IFBAF_STICKY;
@@ -2747,17 +2787,22 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t
 
 		if ((error = bridge_rtnode_insert(sc, brt)) != 0) {
 			uma_zfree(V_bridge_rtnode_zone, brt);
+			BRIDGE_UNLOCK(sc);
 			return (error);
 		}
 		brt->brt_dst = bif;
 		bif->bif_addrcnt++;
+
+		BRIDGE_UNLOCK(sc);
 	}
 
 	if ((brt->brt_flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC &&
 	    brt->brt_dst != bif) {
+		BRIDGE_LOCK(sc);
 		brt->brt_dst->bif_addrcnt--;
 		brt->brt_dst = bif;
 		brt->brt_dst->bif_addrcnt++;
+		BRIDGE_UNLOCK(sc);
 	}
 
 	if ((flags & IFBAF_TYPEMASK) == IFBAF_DYNAMIC)
@@ -2778,7 +2823,7 @@ bridge_rtlookup(struct bridge_softc *sc, const uint8_t
 {
 	struct bridge_rtnode *brt;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
 
 	if ((brt = bridge_rtnode_lookup(sc, addr, vlan)) == NULL)
 		return (NULL);
@@ -3017,7 +3062,7 @@ bridge_rtnode_lookup(struct bridge_softc *sc, const ui
 	uint32_t hash;
 	int dir;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
 
 	hash = bridge_rthash(sc, addr);
 	CK_LIST_FOREACH(brt, &sc->sc_rthash[hash], brt_hash) {
@@ -3080,6 +3125,18 @@ out:
 	return (0);
 }
 
+static void
+bridge_rtnode_destroy_cb(struct epoch_context *ctx)
+{
+	struct bridge_rtnode *brt;
+
+	brt = __containerof(ctx, struct bridge_rtnode, brt_epoch_ctx);
+
+	CURVNET_SET(brt->brt_vnet);
+	uma_zfree(V_bridge_rtnode_zone, brt);
+	CURVNET_RESTORE();
+}
+
 /*
  * bridge_rtnode_destroy:
  *
@@ -3095,7 +3152,9 @@ bridge_rtnode_destroy(struct bridge_softc *sc, struct 
 	CK_LIST_REMOVE(brt, brt_list);
 	sc->sc_brtcnt--;
 	brt->brt_dst->bif_addrcnt--;
-	uma_zfree(V_bridge_rtnode_zone, brt);
+
+	epoch_call(net_epoch_preempt, &brt->brt_epoch_ctx,
+	    bridge_rtnode_destroy_cb);
 }
 
 /*
@@ -3640,17 +3699,20 @@ bridge_linkstate(struct ifnet *ifp)
 {
 	struct bridge_softc *sc = ifp->if_bridge;
 	struct bridge_iflist *bif;
+	struct epoch_tracker et;
 
-	BRIDGE_LOCK(sc);
+	NET_EPOCH_ENTER_ET(et);
+
 	bif = bridge_lookup_member_if(sc, ifp);
 	if (bif == NULL) {
-		BRIDGE_UNLOCK(sc);
+		NET_EPOCH_EXIT_ET(et);
 		return;
 	}
 	bridge_linkcheck(sc);
-	BRIDGE_UNLOCK(sc);
 
 	bstp_linkstate(&bif->bif_stp);
+
+	NET_EPOCH_EXIT_ET(et);
 }
 
 static void
@@ -3659,7 +3721,8 @@ bridge_linkcheck(struct bridge_softc *sc)
 	struct bridge_iflist *bif;
 	int new_link, hasls;
 
-	BRIDGE_LOCK_ASSERT(sc);
+	MPASS(in_epoch(net_epoch_preempt));
+
 	new_link = LINK_STATE_DOWN;
 	hasls = 0;
 	/* Our link is considered up if at least one of our ports is active */


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