commit b96ea771e0c1916eeaee6b979a5f9d7848c0ed59
author Steven Moreland <smoreland@google.com> Thu Jul 16 22:43:02 2020 +0000
committer Steven Moreland <smoreland@google.com> Tue Jul 21 01:07:54 2020 +0000
tree 01605eba06f39cc3d4c0a49fe4e1ff22fe6f4c54
parent c7481bbeb35c8c64cf21e79794dafb615197dbf1

libbinder: setMinSchedulerPolicy

This function on BBinder allows the minimum scheduling priority for
incoming binder transactions to be set by the binder driver. This
functionality was originally developed for libhwbinder and ported here.
The main difference from libhwbider is that invalid priority sets cause
an abort, whereas for libhwbinder, an error is returned. Unfortunately,
that error is frequently ignored, and since this reflects static
configuration, abort is considered a benefit.

Note, since these functions aren't available in the R GSI, they have
been marked as weak here, and are available optionally.
(cherry picked from commit bf1915b6d85d3c222200ef5d5fd7745ed299b17b)

Bug: 149933095
Test: binderLibTest
Change-Id: Ie93aebb09f4142cd66d841ca8b3ca39d1e0bb75e
Merged-In: Ie93aebb09f4142cd66d841ca8b3ca39d1e0bb75e

libs/binder/tests/binderLibTest.cpp

diff --git a/libs/binder/tests/binderLibTest.cpp b/libs/binder/tests/binderLibTest.cpp
index 40de2db..917751e 100644
--- a/libs/binder/tests/binderLibTest.cpp
+++ b/libs/binder/tests/binderLibTest.cpp
@@ -50,6 +50,9 @@
 static char *binderserversuffix;
 static char binderserverarg[] = "--binderserver";
 
+static constexpr int kSchedPolicy = SCHED_RR;
+static constexpr int kSchedPriority = 7;
+
 static String16 binderLibTestServiceName = String16("test.binderLib");
 
 enum BinderLibTestTranscationCode {
@@ -75,6 +78,7 @@
     BINDER_LIB_TEST_GET_PTR_SIZE_TRANSACTION,
     BINDER_LIB_TEST_CREATE_BINDER_TRANSACTION,
     BINDER_LIB_TEST_GET_WORK_SOURCE_TRANSACTION,
+    BINDER_LIB_TEST_GET_SCHEDULING_POLICY,
     BINDER_LIB_TEST_ECHO_VECTOR,
     BINDER_LIB_TEST_REJECT_BUF,
 };
@@ -1015,6 +1019,22 @@
     EXPECT_EQ(NO_ERROR, ret2);
 }
 
+TEST_F(BinderLibTest, SchedPolicySet) {
+    sp<IBinder> server = addServer();
+    ASSERT_TRUE(server != nullptr);
+
+    Parcel data, reply;
+    status_t ret = server->transact(BINDER_LIB_TEST_GET_SCHEDULING_POLICY, data, &reply);
+    EXPECT_EQ(NO_ERROR, ret);
+
+    int policy = reply.readInt32();
+    int priority = reply.readInt32();
+
+    EXPECT_EQ(kSchedPolicy, policy & (~SCHED_RESET_ON_FORK));
+    EXPECT_EQ(kSchedPriority, priority);
+}
+
+
 TEST_F(BinderLibTest, VectorSent) {
     Parcel data, reply;
     sp<IBinder> server = addServer();
@@ -1332,6 +1352,16 @@
                 reply->writeInt32(IPCThreadState::self()->getCallingWorkSourceUid());
                 return NO_ERROR;
             }
+            case BINDER_LIB_TEST_GET_SCHEDULING_POLICY: {
+                int policy = 0;
+                sched_param param;
+                if (0 != pthread_getschedparam(pthread_self(), &policy, &param)) {
+                    return UNKNOWN_ERROR;
+                }
+                reply->writeInt32(policy);
+                reply->writeInt32(param.sched_priority);
+                return NO_ERROR;
+            }
             case BINDER_LIB_TEST_ECHO_VECTOR: {
                 std::vector<uint64_t> vector;
                 auto err = data.readUint64Vector(&vector);
@@ -1368,6 +1398,8 @@
     {
         sp<BinderLibTestService> testService = new BinderLibTestService(index);
 
+        testService->setMinSchedulerPolicy(kSchedPolicy, kSchedPriority);
+
         /*
          * Normally would also contain functionality as well, but we are only
          * testing the extension mechanism.