Fix and re-enable RecordInfoLockTest; remove no-longer-needed re-entr…

…ancy from RecordInfo.SpinLock() (#409)
microsoft · Feb 26, 2021 · b2292b8 · b2292b8
1 parent e163614
commit b2292b8
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Showing 2 changed files with 7 additions and 54 deletions.
diff --git a/cs/src/core/Index/Common/RecordInfo.cs b/cs/src/core/Index/Common/RecordInfo.cs
@@ -144,45 +144,18 @@ public void Unpin()
             throw new InvalidOperationException();
         }
 #endif
-        /// <summary>
-        /// The RecordInfo locked by this thread, if any.
-        /// </summary>
-        [ThreadStatic]
-        internal static RecordInfo* threadLockedRecord;
-
-        /// <summary>
-        /// The number of times the current thread has (re-)entered the lock.
-        /// </summary>
-        [ThreadStatic]
-        internal static int threadLockedRecordEntryCount;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void SpinLock()
         {
-            // Check for a re-entrant lock.
-            if (threadLockedRecord == (RecordInfo*)Unsafe.AsPointer(ref this))
-            {
-                Debug.Assert(threadLockedRecordEntryCount > 0);
-                ++threadLockedRecordEntryCount;
-                return;
-            }
-
-            // RecordInfo locking is intended for use in concurrent callbacks only (ConcurrentReader, ConcurrentWriter, InPlaceUpdater),
-            // so only the RecordInfo for that callback should be locked. A different RecordInfo being locked implies a missing Unlock.
-            Debug.Assert(threadLockedRecord == null);
-            Debug.Assert(threadLockedRecordEntryCount == 0);
             while (true)
             {
                 long expected_word = word;
                 if ((expected_word & kLatchBitMask) == 0)
                 {
                     var found_word = Interlocked.CompareExchange(ref word, expected_word | kLatchBitMask, expected_word);
                     if (found_word == expected_word)
-                    {
-                        threadLockedRecord = (RecordInfo*)Unsafe.AsPointer(ref this);
-                        threadLockedRecordEntryCount = 1;
                         return;
-                    }
                 }
                 Thread.Yield();
             }
@@ -191,16 +164,7 @@ public void SpinLock()
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Unlock()
         {
-            Debug.Assert(threadLockedRecord == (RecordInfo*)Unsafe.AsPointer(ref this));
-            if (threadLockedRecord == (RecordInfo*)Unsafe.AsPointer(ref this))
-            {
-                Debug.Assert(threadLockedRecordEntryCount > 0);
-                if (--threadLockedRecordEntryCount == 0)
-                {
-                    word &= ~kLatchBitMask;
-                    threadLockedRecord = null;
-                }
-            }
+            word &= ~kLatchBitMask;
         }
 
         public bool IsNull()

diff --git a/cs/test/LockTests.cs b/cs/test/LockTests.cs
@@ -63,27 +63,16 @@ public void TearDown()
             log = null;
         }
 
+        [Test]
         public unsafe void RecordInfoLockTest()
         {
-            // Re-entrancy check
-            static void checkLatch(RecordInfo* ptr, long count)
+            for (var ii = 0; ii < 5; ++ii)
             {
-                Assert.IsTrue(RecordInfo.threadLockedRecord == ptr);
-                Assert.IsTrue(RecordInfo.threadLockedRecordEntryCount == count);
+                RecordInfo recordInfo = new RecordInfo();
+                RecordInfo* ri = &recordInfo;
+
+                XLockTest(() => ri->SpinLock(), () => ri->Unlock());
             }
-            RecordInfo recordInfo = new RecordInfo();
-            RecordInfo* ri = (RecordInfo*)Unsafe.AsPointer(ref recordInfo);
-            checkLatch(null, 0);
-            recordInfo.SpinLock();
-            checkLatch(ri, 1);
-            recordInfo.SpinLock();
-            checkLatch(ri, 2);
-            recordInfo.Unlock();
-            checkLatch(ri, 1);
-            recordInfo.Unlock();
-            checkLatch(null, 0);
-
-            XLockTest(() => recordInfo.SpinLock(), () => recordInfo.Unlock());
         }
 
         private void XLockTest(Action locker, Action unlocker)