Have lockstat(1) trace locks by name rather than by address.

Previously, lockstat(1) would use a lock's address as its identifier when
consuming data describing lock contention and hold events. After collecting
the requested data, it would use ksyms(4) to resolve lock addresses to
names. Of course, this doesn't work too well for locks contained in
dynamically-allocated memory. This change modifies lockstat(1) to trace the
lock names obtained from the base struct lock_object instead, leading to
output that is generally much more useful.

This change also removes the -c option, which is used to coalesce data for
locks in an array. It's not possible to support this option without also
tracing lock addresses, and since lock arrays in which the lock names are
distinct are not very common in FreeBSD, it's simpler to just remove the
option.

Reviewed by:	avg (earlier revision)
Differential Revision:	https://reviews.freebsd.org/D3661

2 files changed, 66 insertions, 4 deletions

diff --git a/cddl/contrib/opensolaris/cmd/lockstat/lockstat.1 b/cddl/contrib/opensolaris/cmd/lockstat/lockstat.1
index 1aa73cc..5524968 100644
--- a/cddl/contrib/opensolaris/cmd/lockstat/lockstat.1
+++ b/cddl/contrib/opensolaris/cmd/lockstat/lockstat.1
@@ -21,7 +21,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 24, 2015
+.Dd September 29, 2015
 .Dt LOCKSTAT 1
 .Os
 .Sh NAME
@@ -38,7 +38,7 @@
 .Op Fl d Ar duration
 .Op Fl f Ar function Oo Ns , Ns Ar size Oc
 .Op Fl T
-.Op Fl ckgwWRpP
+.Op Fl kgwWRpP
 .Op Fl D Ar count
 .Op Fl o filename
 .Op Fl x Ar opt Oo Ns = Ns Ar val Oc
@@ -172,8 +172,6 @@ This is off by default.
 .El
 .Ss Data Reporting
 .Bl -tag -width indent
-.It Fl c
-Coalesce lock data for lock arrays.
 .It Fl D Ar count
 Only display the top
 .Ar count
diff --git a/cddl/contrib/opensolaris/cmd/lockstat/lockstat.c b/cddl/contrib/opensolaris/cmd/lockstat/lockstat.c
index b59bee7..38bf681 100644
--- a/cddl/contrib/opensolaris/cmd/lockstat/lockstat.c
+++ b/cddl/contrib/opensolaris/cmd/lockstat/lockstat.c
@@ -65,7 +65,11 @@ typedef	uintptr_t	pc_t;
 
 typedef struct lsrec {
 	struct lsrec	*ls_next;	/* next in hash chain */
+#ifdef illumos
 	uintptr_t	ls_lock;	/* lock address */
+#else
+	char		*ls_lock;	/* lock name */
+#endif
 	uintptr_t	ls_caller;	/* caller address */
 	uint32_t	ls_count;	/* cumulative event count */
 	uint32_t	ls_event;	/* type of event */
@@ -338,7 +342,9 @@ usage(void)
 	    "  -d duration     only watch events longer than <duration>\n"
 	    "  -T              trace (rather than sample) events\n"
 	    "\nData reporting options:\n\n"
+#ifdef illumos
 	    "  -c              coalesce lock data for arrays like pse_mutex[]\n"
+#endif
 	    "  -k              coalesce PCs within functions\n"
 	    "  -g              show total events generated by function\n"
 	    "  -w              wherever: don't distinguish events by caller\n"
@@ -381,12 +387,16 @@ lockcmp(lsrec_t *a, lsrec_t *b)
 	if (a->ls_caller > b->ls_caller)
 		return (1);
 
+#ifdef illumos
 	if (a->ls_lock < b->ls_lock)
 		return (-1);
 	if (a->ls_lock > b->ls_lock)
 		return (1);
 
 	return (0);
+#else
+	return (strcmp(a->ls_lock, b->ls_lock));
+#endif
 }
 
 static int
@@ -424,26 +434,40 @@ lockcmp_anywhere(lsrec_t *a, lsrec_t *b)
 	if (a->ls_event > b->ls_event)
 		return (1);
 
+#ifdef illumos
 	if (a->ls_lock < b->ls_lock)
 		return (-1);
 	if (a->ls_lock > b->ls_lock)
 		return (1);
 
 	return (0);
+#else
+	return (strcmp(a->ls_lock, b->ls_lock));
+#endif
 }
 
 static int
 lock_and_count_cmp_anywhere(lsrec_t *a, lsrec_t *b)
 {
+#ifndef illumos
+	int cmp;
+#endif
+
 	if (a->ls_event < b->ls_event)
 		return (-1);
 	if (a->ls_event > b->ls_event)
 		return (1);
 
+#ifdef illumos
 	if (a->ls_lock < b->ls_lock)
 		return (-1);
 	if (a->ls_lock > b->ls_lock)
 		return (1);
+#else
+	cmp = strcmp(a->ls_lock, b->ls_lock);
+	if (cmp != 0)
+		return (cmp);
+#endif
 
 	return (b->ls_count - a->ls_count);
 }
@@ -698,7 +722,11 @@ dprog_addevent(int event)
 		caller = "(uintptr_t)arg0";
 		arg1 = "arg2";
 	} else {
+#ifdef illumos
 		arg0 = "(uintptr_t)arg0";
+#else
+		arg0 = "stringof(args[0]->lock_object.lo_name)";
+#endif
 		caller = "caller";
 	}
 
@@ -912,12 +940,17 @@ lsrec_fill(lsrec_t *lsrec, const dtrace_recdesc_t *rec, int nrecs, caddr_t data)
 	lsrec->ls_event = (uint32_t)*((uint64_t *)(data + rec->dtrd_offset));
 	rec++;
 
+#ifdef illumos
 	if (rec->dtrd_size != sizeof (uintptr_t))
 		fail(0, "bad lock address size in second record");
 
 	/* LINTED - alignment */
 	lsrec->ls_lock = *((uintptr_t *)(data + rec->dtrd_offset));
 	rec++;
+#else
+	lsrec->ls_lock = strdup((const char *)(data + rec->dtrd_offset));
+	rec++;
+#endif
 
 	if (rec->dtrd_size != sizeof (uintptr_t))
 		fail(0, "bad caller size in third record");
@@ -1224,9 +1257,11 @@ main(int argc, char **argv)
 			events_specified = 1;
 			break;
 
+#ifdef illumos
 		case 'c':
 			g_cflag = 1;
 			break;
+#endif
 
 		case 'k':
 			g_kflag = 1;
@@ -1539,6 +1574,9 @@ main(int argc, char **argv)
 					caller_in_stack = 1;
 				bcopy(oldlsp, lsp, LS_TIME);
 				lsp->ls_caller = oldlsp->ls_stack[fr];
+#ifndef illumos
+				lsp->ls_lock = strdup(oldlsp->ls_lock);
+#endif
 				/* LINTED - alignment */
 				lsp = (lsrec_t *)((char *)lsp + LS_TIME);
 			}
@@ -1547,6 +1585,9 @@ main(int argc, char **argv)
 				/* LINTED - alignment */
 				lsp = (lsrec_t *)((char *)lsp + LS_TIME);
 			}
+#ifndef illumos
+			free(oldlsp->ls_lock);
+#endif
 		}
 		g_nrecs = g_nrecs_used =
 		    ((uintptr_t)lsp - (uintptr_t)newlsp) / LS_TIME;
@@ -1604,8 +1645,10 @@ main(int argc, char **argv)
 		for (i = 0; i < g_nrecs_used; i++) {
 			int fr;
 			lsp = sort_buf[i];
+#ifdef illumos
 			if (g_cflag)
 				coalesce_symbol(&lsp->ls_lock);
+#endif
 			if (g_kflag) {
 				for (fr = 0; fr < g_stkdepth; fr++)
 					coalesce_symbol(&lsp->ls_stack[fr]);
@@ -1659,6 +1702,15 @@ main(int argc, char **argv)
 		first = current;
 	}
 
+#ifndef illumos
+	/*
+	 * Free lock name buffers
+	 */
+	for (i = 0, lsp = (lsrec_t *)data_buf; i < g_nrecs_used; i++,
+	    lsp = (lsrec_t *)((char *)lsp + g_recsize))
+		free(lsp->ls_lock);
+#endif
+
 	return (0);
 }
 
@@ -1748,8 +1800,12 @@ report_stats(FILE *out, lsrec_t **sort_buf, size_t nrecs, uint64_t total_count,
 
 			(void) fprintf(out, "%u %u",
 			    lsp->ls_event, lsp->ls_count);
+#ifdef illumos
 			(void) fprintf(out, " %s",
 			    format_symbol(buf, lsp->ls_lock, g_cflag));
+#else
+			(void) fprintf(out, " %s", lsp->ls_lock);
+#endif
 			(void) fprintf(out, " %s",
 			    format_symbol(buf, lsp->ls_caller, 0));
 			(void) fprintf(out, " %f",
@@ -1811,8 +1867,12 @@ report_stats(FILE *out, lsrec_t **sort_buf, size_t nrecs, uint64_t total_count,
 		(void) fprintf(out, "%4.2f %8s ",
 		    (double)lsp->ls_refcnt / lsp->ls_count, buf);
 
+#ifdef illumos
 		(void) fprintf(out, "%-22s ",
 		    format_symbol(buf, lsp->ls_lock, g_cflag));
+#else
+		(void) fprintf(out, "%-22s ", lsp->ls_lock);
+#endif
 
 		(void) fprintf(out, "%-24s\n",
 		    format_symbol(buf, lsp->ls_caller, 0));
@@ -1908,7 +1968,11 @@ report_trace(FILE *out, lsrec_t **sort_buf)
 		(void) fprintf(out, "%2d  %10llu  %11p  %-24s  %-24s\n",
 		    lsp->ls_event, (unsigned long long)lsp->ls_time,
 		    (void *)lsp->ls_next,
+#ifdef illumos
 		    format_symbol(buf, lsp->ls_lock, 0),
+#else
+		    lsp->ls_lock,
+#endif
 		    format_symbol(buf2, lsp->ls_caller, 0));
 
 		if (rectype <= LS_STACK(0))