Make dbufstat work on FreeBSD

With procfs_list kstats implemented for FreeBSD, dbufs are now exposed
as kstat.zfs.misc.dbufs.

On FreeBSD, dbufstats can use the sysctl instead of procfs when no
input file has been given.

Enable the dbufstats tests on FreeBSD.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes #11008

cmd/dbufstat/dbufstat.in

@@ -113,6 +113,21 @@ cmd = ("Usage: dbufstat [-bdhnrtvx] [-i file] [-f fields] [-o file] "
 raw = 0
 
 
+if sys.platform.startswith("freebsd"):
+    import io
+    # Requires py-sysctl on FreeBSD
+    import sysctl
+
+    def default_ifile():
+        dbufs = sysctl.filter("kstat.zfs.misc.dbufs")[0].value
+        sys.stdin = io.StringIO(dbufs)
+        return "-"
+
+elif sys.platform.startswith("linux"):
+    def default_ifile():
+        return "/proc/spl/kstat/zfs/dbufs"
+
+
 def print_incompat_helper(incompat):
     cnt = 0
     for key in sorted(incompat):
@@ -645,7 +660,7 @@ def main():
             sys.exit(1)
 
     if not ifile:
-        ifile = '/proc/spl/kstat/zfs/dbufs'
+        ifile = default_ifile()
 
     if ifile is not "-":
         try:

module/os/freebsd/spl/spl_kstat.c

@@ -231,6 +231,7 @@ restart:
 	}
 	free(ksp->ks_raw_buf, M_TEMP);
 	mutex_exit(ksp->ks_lock);
+	sbuf_trim(sb);
 	rc = sbuf_finish(sb);
 	if (rc == 0)
 		rc = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb));

tests/runfiles/common.run

@@ -30,6 +30,11 @@ tests = ['alloc_class_001_pos', 'alloc_class_002_neg', 'alloc_class_003_pos',
     'alloc_class_013_pos']
 tags = ['functional', 'alloc_class']
 
+[tests/functional/arc]
+tests = ['dbufstats_001_pos', 'dbufstats_002_pos', 'dbufstats_003_pos',
+    'arcstats_runtime_tuning']
+tags = ['functional', 'arc']
+
 [tests/functional/atime]
 tests = ['atime_001_pos', 'atime_002_neg', 'root_atime_off', 'root_atime_on']
 tags = ['functional', 'atime']

tests/runfiles/linux.run

@@ -26,11 +26,6 @@ tags = ['functional']
 tests = ['posix_001_pos', 'posix_002_pos', 'posix_003_pos']
 tags = ['functional', 'acl', 'posix']
 
-[tests/functional/arc:Linux]
-tests = ['dbufstats_001_pos', 'dbufstats_002_pos', 'dbufstats_003_pos',
-    'arcstats_runtime_tuning']
-tags = ['functional', 'arc']
-
 [tests/functional/atime:Linux]
 tests = ['atime_003_pos', 'root_relatime_on']
 tags = ['functional', 'atime']

tests/zfs-tests/include/libtest.shlib

@@ -4154,18 +4154,36 @@ function ls_xattr # path
 	esac
 }
 
+function kstat # stat flags?
+{
+	typeset stat=$1
+	typeset flags=${2-"-n"}
+
+	case $(uname) in
+	FreeBSD)
+		sysctl $flags kstat.zfs.misc.$stat
+		;;
+	Linux)
+		typeset zfs_kstat="/proc/spl/kstat/zfs/$stat"
+		[[ -f "$zfs_kstat" ]] || return 1
+		cat $zfs_kstat
+		;;
+	*)
+		false
+		;;
+	esac
+}
+
 function get_arcstat # stat
 {
 	typeset stat=$1
 
 	case $(uname) in
 	FreeBSD)
-		sysctl -n kstat.zfs.misc.arcstats.$stat
+		kstat arcstats.$stat
 		;;
 	Linux)
-		typeset zfs_arcstats="/proc/spl/kstat/zfs/arcstats"
-		[[ -f "$zfs_arcstats" ]] || return 1
-		grep $stat $zfs_arcstats | awk '{print $3}'
+		kstat arcstats | awk "/$stat/ { print \$3 }"
 		;;
 	*)
 		false

tests/zfs-tests/tests/functional/arc/dbufstats_001_pos.ksh

@@ -55,7 +55,13 @@ function testdbufstat # stat_name dbufstat_filter
 
         [[ -n "$2" ]] && filter="-F $2"
 
-	from_dbufstat=$(grep -w "$name" "$DBUFSTATS_FILE" | awk '{ print $3 }')
+	if is_linux; then
+		from_dbufstat=$(grep -w "$name" "$DBUFSTATS_FILE" |
+		    awk '{ print $3 }')
+	else
+		from_dbufstat=$(awk "/dbufstats\.$name:/ { print \$2 }" \
+		    "$DBUFSTATS_FILE")
+	fi
 	from_dbufs=$(dbufstat -bxn -i "$DBUFS_FILE" "$filter" | wc -l)
 
 	within_tolerance $from_dbufstat $from_dbufs 15 \
@@ -71,8 +77,8 @@ log_onexit cleanup
 log_must file_write -o create -f "$TESTDIR/file" -b 1048576 -c 20 -d R
 log_must zpool sync
 
-log_must eval "cat /proc/spl/kstat/zfs/dbufs > $DBUFS_FILE"
-log_must eval "cat /proc/spl/kstat/zfs/dbufstats > $DBUFSTATS_FILE"
+log_must eval "kstat dbufs > $DBUFS_FILE"
+log_must eval "kstat dbufstats '' > $DBUFSTATS_FILE"
 
 for level in {0..11}; do
 	testdbufstat "cache_level_$level" "dbc=1,level=$level"

tests/zfs-tests/tests/functional/arc/dbufstats_002_pos.ksh

@@ -58,10 +58,10 @@ log_onexit cleanup
 log_must file_write -o create -f "$TESTDIR/file" -b 1048576 -c 1 -d R
 log_must zpool sync
 
-objid=$(stat --format="%i" "$TESTDIR/file")
+objid=$(get_objnum "$TESTDIR/file")
 log_note "Object ID for $TESTDIR/file is $objid"
 
-log_must eval "cat /proc/spl/kstat/zfs/dbufs > $DBUFS_FILE"
+log_must eval "kstat dbufs > $DBUFS_FILE"
 dbuf=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
 mru=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
 mfu=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)
@@ -70,7 +70,7 @@ verify_ne "0" "$mru" "mru count"
 verify_eq "0" "$mfu" "mfu count"
 
 log_must eval "cat $TESTDIR/file > /dev/null"
-log_must eval "cat /proc/spl/kstat/zfs/dbufs > $DBUFS_FILE"
+log_must eval "kstat dbufs > $DBUFS_FILE"
 dbuf=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
 mru=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
 mfu=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)