Remove --disable-spinlocks.

A later change will require atomic support, so it wouldn't make sense
for a hypothetical new system not to be able to implement spinlocks.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (concept, not the patch)
Reviewed-by: Andres Freund <andres@anarazel.de> (concept, not the patch)
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us

1 files changed, 0 insertions, 86 deletions

diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c
index 45a6ad3c49e..14aad5a0c6e 100644
--- a/src/test/regress/regress.c
+++ b/src/test/regress/regress.c
@@ -887,91 +887,7 @@ test_spinlock(void)
 		if (memcmp(struct_w_lock.data_after, "ef12", 4) != 0)
 			elog(ERROR, "padding after spinlock modified");
 	}
-
-	/*
-	 * Ensure that allocating more than INT32_MAX emulated spinlocks works.
-	 * That's interesting because the spinlock emulation uses a 32bit integer
-	 * to map spinlocks onto semaphores. There've been bugs...
-	 */
-#ifndef HAVE_SPINLOCKS
-	{
-		/*
-		 * Initialize enough spinlocks to advance counter close to wraparound.
-		 * It's too expensive to perform acquire/release for each, as those
-		 * may be syscalls when the spinlock emulation is used (and even just
-		 * atomic TAS would be expensive).
-		 */
-		for (uint32 i = 0; i < INT32_MAX - 100000; i++)
-		{
-			slock_t		lock;
-
-			SpinLockInit(&lock);
-		}
-
-		for (uint32 i = 0; i < 200000; i++)
-		{
-			slock_t		lock;
-
-			SpinLockInit(&lock);
-
-			SpinLockAcquire(&lock);
-			SpinLockRelease(&lock);
-			SpinLockAcquire(&lock);
-			SpinLockRelease(&lock);
-		}
-	}
-#endif
-}
-
-/*
- * Verify that performing atomic ops inside a spinlock isn't a
- * problem. Realistically that's only going to be a problem when both
- * --disable-spinlocks and --disable-atomics are used, but it's cheap enough
- * to just always test.
- *
- * The test works by initializing enough atomics that we'd conflict if there
- * were an overlap between a spinlock and an atomic by holding a spinlock
- * while manipulating more than NUM_SPINLOCK_SEMAPHORES atomics.
- *
- * NUM_TEST_ATOMICS doesn't really need to be more than
- * NUM_SPINLOCK_SEMAPHORES, but it seems better to test a bit more
- * extensively.
- */
-static void
-test_atomic_spin_nest(void)
-{
-	slock_t		lock;
-#define NUM_TEST_ATOMICS (NUM_SPINLOCK_SEMAPHORES + NUM_ATOMICS_SEMAPHORES + 27)
-	pg_atomic_uint32 atomics32[NUM_TEST_ATOMICS];
-	pg_atomic_uint64 atomics64[NUM_TEST_ATOMICS];
-
-	SpinLockInit(&lock);
-
-	for (int i = 0; i < NUM_TEST_ATOMICS; i++)
-	{
-		pg_atomic_init_u32(&atomics32[i], 0);
-		pg_atomic_init_u64(&atomics64[i], 0);
-	}
-
-	/* just so it's not all zeroes */
-	for (int i = 0; i < NUM_TEST_ATOMICS; i++)
-	{
-		EXPECT_EQ_U32(pg_atomic_fetch_add_u32(&atomics32[i], i), 0);
-		EXPECT_EQ_U64(pg_atomic_fetch_add_u64(&atomics64[i], i), 0);
-	}
-
-	/* test whether we can do atomic op with lock held */
-	SpinLockAcquire(&lock);
-	for (int i = 0; i < NUM_TEST_ATOMICS; i++)
-	{
-		EXPECT_EQ_U32(pg_atomic_fetch_sub_u32(&atomics32[i], i), i);
-		EXPECT_EQ_U32(pg_atomic_read_u32(&atomics32[i]), 0);
-		EXPECT_EQ_U64(pg_atomic_fetch_sub_u64(&atomics64[i], i), i);
-		EXPECT_EQ_U64(pg_atomic_read_u64(&atomics64[i]), 0);
-	}
-	SpinLockRelease(&lock);
 }
-#undef NUM_TEST_ATOMICS
 
 PG_FUNCTION_INFO_V1(test_atomic_ops);
 Datum
@@ -989,8 +905,6 @@ test_atomic_ops(PG_FUNCTION_ARGS)
 	 */
 	test_spinlock();
 
-	test_atomic_spin_nest();
-
 	PG_RETURN_BOOL(true);
 }