Skip slow tests when kmemleak is enabled

When running the ZFS Test Suite with a kmemleak enabled kernel
the following test cases run far slower than usual and may hit
their timeout threshold.  Skip the following test cases.

Test: cli_root/zfs_get/zfs_get_009_pos (run as root) [55:43]
Test: cli_root/zpool_clear/zpool_clear_001_pos (run as root) [11:32]
Test: cli_root/zpool_create/zpool_create_024_pos (run as root) [11:01]
Test: features/async_destroy/async_destroy_001_pos (run as root) [41:15]
Test: inheritance/inherit_001_pos (run as root) [09:08]

Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #5479 
Closes #5480

tests/zfs-tests/include/libtest.shlib

@@ -57,6 +57,19 @@ function is_32bit
 	fi
 }
 
+# Determine if kmemleak is enabled
+#
+# Return 0 if kmemleak is enabled, 1 if otherwise
+
+function is_kmemleak
+{
+	if is_linux && [[ -e /sys/kernel/debug/kmemleak ]]; then
+		return 0
+	else
+		return 1
+	fi
+}
+
 # Determine whether a dataset is mounted
 #
 # $1 dataset name

tests/zfs-tests/tests/functional/cli_root/zfs_get/zfs_get_009_pos.ksh

@@ -41,6 +41,11 @@
 
 verify_runnable "both"
 
+# See issue: https://github.com/zfsonlinux/zfs/issues/5479
+if is_kmemleak; then
+	log_unsupported "Test case runs slowly when kmemleak is enabled"
+fi
+
 log_assert "'zfs get -d <n>' should get expected output."
 log_onexit depth_fs_cleanup
 

tests/zfs-tests/tests/functional/cli_root/zpool_clear/zpool_clear_001_pos.ksh

@@ -45,6 +45,11 @@
 
 verify_runnable "global"
 
+# See issue: https://github.com/zfsonlinux/zfs/issues/5479
+if is_kmemleak; then
+	log_unsupported "Test case runs slowly when kmemleak is enabled"
+fi
+
 function cleanup
 {
         poolexists $TESTPOOL1 && \
@@ -55,7 +60,6 @@ function cleanup
         done
 }
 
-
 log_assert "Verify 'zpool clear' can clear errors of a storage pool."
 log_onexit cleanup
 

tests/zfs-tests/tests/functional/cli_root/zpool_create/zpool_create_024_pos.ksh

@@ -39,6 +39,11 @@
 
 verify_runnable "global"
 
+# See issue: https://github.com/zfsonlinux/zfs/issues/5479
+if is_kmemleak; then
+	log_unsupported "Test case runs slowly when kmemleak is enabled"
+fi
+
 function cleanup
 {
 	if [[ -n "$child_pids" ]]; then

tests/zfs-tests/tests/functional/features/async_destroy/async_destroy_001_pos.ksh

@@ -46,6 +46,11 @@ TEST_FS=$TESTPOOL/async_destroy
 
 verify_runnable "both"
 
+# See issue: https://github.com/zfsonlinux/zfs/issues/5479
+if is_kmemleak; then
+	log_unsupported "Test case runs slowly when kmemleak is enabled"
+fi
+
 function cleanup
 {
 	datasetexists $TEST_FS && log_must $ZFS destroy $TEST_FS

tests/zfs-tests/tests/functional/inheritance/inherit_001_pos.ksh

@@ -45,6 +45,11 @@
 
 verify_runnable "global"
 
+# See issue: https://github.com/zfsonlinux/zfs/issues/5479
+if is_kmemleak; then
+	log_unsupported "Test case runs slowly when kmemleak is enabled"
+fi
+
 log_assert "Test properties are inherited correctly"
 
 #