cgroup/cpuset: Enable invalid to valid local partition transition

When a local partition becomes invalid, it won't transition back to
valid partition automatically if a proper "cpuset.cpus.exclusive" or
"cpuset.cpus" change is made. Instead, system administrators have to
explicitly echo "root" or "isolated" into the "cpuset.cpus.partition"
file at the partition root.

This patch now enables the automatic transition of an invalid local
partition back to valid when there is a proper "cpuset.cpus.exclusive"
or "cpuset.cpus" change.

Automatic transition of an invalid remote partition to a valid one,
however, is not covered by this patch. They still need an explicit
write to "cpuset.cpus.partition" to become valid again.

The test_cpuset_prs.sh test script is updated to add new test cases to
test this automatic state transition.

Reported-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/lkml/9777f0d2-2fdf-41cb-bd01-19c52939ef42@arm.com
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 14 insertions, 7 deletions

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 0f4f4a57ae12..a6e9848189d6 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -220,7 +220,8 @@ test_isolated()
 #      +- B1
 #
 #  P<v> = set cpus.partition (0:member, 1:root, 2:isolated)
-#  C<l> = add cpu-list
+#  C<l> = add cpu-list to cpuset.cpus
+#  X<l> = add cpu-list to cpuset.cpus.exclusive
 #  S<p> = use prefix in subtree_control
 #  T    = put a task into cgroup
 #  O<c>=<v> = Write <v> to CPU online file of <c>
@@ -318,16 +319,19 @@ TEST_MATRIX=(
 	" C0-3:S+ C1-3:S+  C2      .    X2-3   X2-3   T:P2:O2=0 O2=1 0 A1:0-3,A2:1-3,A3:2 A1:P0,A3:P-2"
 
 	# cpus.exclusive.effective clearing test
-	" C0-3:S+ C1-3:S+  C2      .   X2-3:X    .      .      .      0 A1:0-3,A2:1-3,A3:2,XA1:"
+	" C0-3:S+ C1-3:S+  C2      .   X2-3:X    .      .      .     0 A1:0-3,A2:1-3,A3:2,XA1:"
 
-	# Invalid to valid remote partition indirect transition test via member
-	" C0-3:S+   C1-3    .      .      .    X3:P2    .      .      0 A1:0-3,A2:1-3,XA2: A2:P-2"
+	# Invalid to valid remote partition transition test
+	" C0-3:S+   C1-3    .      .      .    X3:P2    .      .     0 A1:0-3,A2:1-3,XA2: A2:P-2"
 	" C0-3:S+ C1-3:X3:P2
-			    .      .    X2-3   P0:P2    .      .      0 A1:0-2,A2:3,XA2:3 A2:P2 3"
+			    .      .    X2-3    P2      .      .     0 A1:0-2,A2:3,XA2:3 A2:P2 3"
 
 	# Invalid to valid local partition direct transition tests
-	" C1-3:S+:P2 C2-3:X1:P2 .  .      .      .      .      .      0 A1:1-3,XA1:1-3,A2:2-3:XA2: A1:P2,A2:P-2 1-3"
-	" C1-3:S+:P2 C2-3:X1:P2 .  .      .    X3:P2    .      .      0 A1:1-2,XA1:1-3,A2:3:XA2:3 A1:P2,A2:P2 1-3"
+	" C1-3:S+:P2 C2-3:X1:P2 .  .      .      .      .      .     0 A1:1-3,XA1:1-3,A2:2-3:XA2: A1:P2,A2:P-2 1-3"
+	" C1-3:S+:P2 C2-3:X1:P2 .  .      .    X3:P2    .      .     0 A1:1-2,XA1:1-3,A2:3:XA2:3 A1:P2,A2:P2 1-3"
+	"  C0-3:P2   .      .    C4-6   C0-4     .      .      .     0 A1:0-4,B1:4-6 A1:P-2,B1:P0"
+	"  C0-3:P2   .      .    C4-6 C0-4:C0-3  .      .      .     0 A1:0-3,B1:4-6 A1:P2,B1:P0 0-3"
+	"  C0-3:P2   .      .  C3-5:C4-5  .      .      .      .     0 A1:0-3,B1:4-5 A1:P2,B1:P0 0-3"
 
 	# Local partition invalidation tests
 	" C0-3:X1-3:S+:P2 C1-3:X2-3:S+:P2 C2-3:X3:P2 \
@@ -336,6 +340,9 @@ TEST_MATRIX=(
 				   .      .     X4      .      .     0 A1:1-3,A2:1-3,A3:2-3,XA2:,XA3: A1:P2,A2:P-2,A3:P-2 1-3"
 	" C0-3:X1-3:S+:P2 C1-3:X2-3:S+:P2 C2-3:X3:P2 \
 				   .      .     C4      .      .     0 A1:1-3,A2:1-3,A3:2-3,XA2:,XA3: A1:P2,A2:P-2,A3:P-2 1-3"
+	# Local partition CPU change tests
+	" C0-5:S+:P2 C4-5:S+:P1 .  .      .    C3-5     .      .     0 A1:0-2,A2:3-5 A1:P2,A2:P1 0-2"
+	" C0-5:S+:P2 C4-5:S+:P1 .  .    C1-5     .      .      .     0 A1:1-3,A2:4-5 A1:P2,A2:P1 1-3"
 
 	# cpus_allowed/exclusive_cpus update tests
 	" C0-3:X2-3:S+ C1-3:X2-3:S+ C2-3:X2-3 \