PERFORCE change 127600 for review

[Marko Zec]

http://perforce.freebsd.org/chv.cgi?CH=127600

Change 127600 by zec at zec_tca51 on 2007/10/16 11:52:31

	Hold a spin mutex when updating CPU usage state and / or
	traversing through the list of cpu accounting containers (in
	statclock() we cannot hold a default mutex).  This shouldn't
	be happening more often than ~ 130 * number_of_processors 
	times per second, so hopefully the introduction of this
	new spin mutex shouldn't choke the system too much.
	
	Nuke periodic conversion from fixed point representation of
	CPU usage averages to integers, together with sysctls that
	were exposing those ints to userland.  We'll be doing the
	conversion only when requested, and export the state to
	userland through the vimage API.

Affected files ...

.. //depot/projects/vimage/src/sys/kern/kern_clock.c#10 edit
.. //depot/projects/vimage/src/sys/kern/kern_vimage.c#44 edit
.. //depot/projects/vimage/src/sys/sys/vimage.h#43 edit

Differences ...

==== //depot/projects/vimage/src/sys/kern/kern_clock.c#10 (text+ko) ====

@@ -480,7 +480,7 @@
 			atomic_add_long(&vprocg_iter->_cp_time[sel], 1);
 
 	/* Per-vcpu average accounting */
-	/* LOCKING!!!! XXX */
+	mtx_lock_spin(&vcpu_list_mtx);
 	tot_acc_statcalls++;
 	if (!TD_IS_IDLETHREAD(td))
 		V_acc_statcalls++;
@@ -500,15 +500,10 @@
 			V_avg1_fixp = (V_avg1_fixp + avg0 + 1) >> 1;
 			V_avg2_fixp = (15 * V_avg2_fixp + avg0 + 15) >> 4;
 			V_acc_statcalls = 0;
-			/*
-			 * Convert fixp notation to percents for export to
-			 * userspace via sysctls - this will go away soon.
-			 */
-			V_avg1_uint = (V_avg1_fixp * 100 + 0x8000) >> 16;
-			V_avg2_uint = (V_avg2_fixp * 100 + 0x8000) >> 16;
 		}
 		tot_acc_statcalls = 0;
 	}
+	mtx_unlock_spin(&vcpu_list_mtx);
 #endif
 
 	/* Update resource usage integrals and maximums. */

==== //depot/projects/vimage/src/sys/kern/kern_vimage.c#44 (text+ko) ====

@@ -115,6 +115,8 @@
 struct mtx vnet_list_refc_mtx;
 int vnet_list_refc = 0;
 
+struct mtx vcpu_list_mtx;
+
 #define VNET_LIST_LOCK()						\
 	mtx_lock(&vnet_list_refc_mtx);					\
 	while (vnet_list_refc != 0)					\
@@ -131,11 +133,6 @@
 static TAILQ_HEAD(vnet_modlink_head, vnet_modlink) vnet_modlink_head;
 static TAILQ_HEAD(vnet_modpending_head, vnet_modlink) vnet_modpending_head;
 
-SYSCTL_V_INT(V_CPU, vcpu, _kern, OID_AUTO, avg1_uint, CTLFLAG_RD,
-    avg1_uint, 0, "Average CPU usage");
-SYSCTL_V_INT(V_CPU, vcpu, _kern, OID_AUTO, avg2_uint, CTLFLAG_RD,
-    avg2_uint, 0, "Average CPU usage");
-
 void vnet_mod_register(vmi)
 	const struct vnet_modinfo *vmi;
 {
@@ -501,12 +498,14 @@
 	case SIOCGPVIMAGE:
 		vi_req->vi_id = vip_r->vi_id;
 		bcopy(&vip_r->vi_name, &vi_req->vi_name,
-			sizeof (vi_req->vi_name));
+		    sizeof (vi_req->vi_name));
 		bcopy(&vip_r->v_procg->_averunnable, &vi_req->averunnable,
-			sizeof (vi_req->averunnable));
+		    sizeof (vi_req->averunnable));
 		vi_req->vi_proc_count = vip_r->v_procg->nprocs;
 		vi_req->vi_if_count = vip_r->v_vnet->ifccnt;
 		vi_req->vi_sock_count = vip_r->v_vnet->sockcnt;
+		vi_req->cp_time_avg =
+		    (vip_r->v_cpu->_avg2_fixp * 10000 + 0x8000) >> 16;
 		break;
 
 	case SIOCSPVIMAGE:
@@ -644,12 +643,19 @@
 		vnet_mod_constructor(vml);
 	CURVNET_RESTORE();
 
-	VNET_LIST_LOCK(); /* XXX should lock other lists separately */
+	VNET_LIST_LOCK();
 	LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le);
+	VNET_LIST_UNLOCK();
+
+	/* XXX locking */
 	LIST_INSERT_HEAD(&vprocg_head, vprocg, vprocg_le);
+
+	mtx_lock_spin(&vcpu_list_mtx);
 	LIST_INSERT_HEAD(&vcpu_head, vcpu, vcpu_le);
+	mtx_unlock_spin(&vcpu_list_mtx);
+
+	/* XXX locking */
 	LIST_INSERT_HEAD(&vimage_head, vip, vi_le);
-	VNET_LIST_UNLOCK();
 
 vi_alloc_done:
 	return (vip);
@@ -814,6 +820,8 @@
 	mtx_init(&vnet_list_refc_mtx, "vnet_list_refc_mtx", NULL, MTX_DEF);
 	cv_init(&vnet_list_condvar, "vnet_list_condvar");
 
+	mtx_init(&vcpu_list_mtx, "vcpu_list_mtx", NULL, MTX_SPIN);
+
 	vi_alloc("default", 0);
 
 	/* We MUST clear curvnet in vi_init_done before going SMP. */

==== //depot/projects/vimage/src/sys/sys/vimage.h#43 (text+ko) ====

@@ -312,8 +312,6 @@
 #define V_acc_statcalls		VCPU(acc_statcalls)
 #define V_avg1_fixp		VCPU(avg1_fixp)
 #define V_avg2_fixp		VCPU(avg2_fixp)
-#define V_avg1_uint		VCPU(avg1_uint)
-#define V_avg2_uint		VCPU(avg2_uint)
 
 #ifdef VIMAGE
 void vnet_mod_register(const struct vnet_modinfo *);
@@ -346,6 +344,7 @@
 extern int vnet_list_refc;
 extern struct mtx vnet_list_refc_mtx;
 extern struct cv vnet_list_condvar;
+extern struct mtx vcpu_list_mtx;
 
 #define VNET_LIST_REF()							\
 	mtx_lock(&vnet_list_refc_mtx);					\
@@ -423,8 +422,6 @@
 	u_int	_acc_statcalls;		/* statclocks since last avg update*/
 	u_int	_avg1_fixp;		/* "fast" avg in 16:16 bit fixedpoint */
 	u_int	_avg2_fixp;		/* "slow" avg in 16:16 bit fixedpoint */
-	u_int	_avg1_uint;		/* (avg1_fixp * 100) >> 16 */
-	u_int	_avg2_uint;		/* (avg2_fixp * 100) >> 16 */
 
 #if 0
 	u_int	cpu_min;		/* Guaranteed CPU share */
@@ -456,7 +453,7 @@
 	char	vi_name[MAXPATHLEN];
 	char	vi_chroot[MAXPATHLEN];
 	char	vi_if_xname[MAXPATHLEN]; /* XXX should be IFNAMSIZ */
-	int	cp_time_avg[CPUSTATES];
+	u_int	cp_time_avg;
 	struct	loadavg averunnable;
 };