MDEV-12534 Use atomic operations whenever available

Allow 64-bit atomic operations on 32-bit systems,
only relying on HAVE_ATOMIC_BUILTINS_64, disregarding
the width of the register file.

Define UNIV_WORD_SIZE correctly on all systems, including Windows.
In MariaDB 10.0 and 10.1, it was incorrectly defined as 4 on
64-bit Windows.

Define HAVE_ATOMIC_BUILTINS_64 on Windows
(64-bit atomics are available on both 32-bit and 64-bit Windows
platforms; the operations were unnecessarily disabled even on
64-bit Windows).

MONITOR_OS_PENDING_READS, MONITOR_OS_PENDING_WRITES: Enable by default.

os_file_n_pending_preads, os_file_n_pending_pwrites,
os_n_pending_reads, os_n_pending_writes: Remove.
Use the monitor counters instead.

os_file_count_mutex: Remove. On a system that does not support
64-bit atomics, monitor_mutex will be used instead.

1 files changed, 44 insertions, 139 deletions

diff --git a/storage/xtradb/os/os0file.cc b/storage/xtradb/os/os0file.cc
index a30b688ad74..48ae49f28e4 100644
--- a/storage/xtradb/os/os0file.cc
+++ b/storage/xtradb/os/os0file.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2009, Percona Inc.
-Copyright (c) 2013, 2017, MariaDB Corporation. All Rights Reserved.
+Copyright (c) 2013, 2017, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted
 by Percona Inc.. Those modifications are
@@ -291,21 +291,6 @@ UNIV_INTERN time_t	os_last_printout;
 
 UNIV_INTERN ibool	os_has_said_disk_full	= FALSE;
 
-#if !defined(UNIV_HOTBACKUP)	\
-    && (!defined(HAVE_ATOMIC_BUILTINS) || UNIV_WORD_SIZE < 8)
-/** The mutex protecting the following counts of pending I/O operations */
-static os_ib_mutex_t	os_file_count_mutex;
-#endif /* !UNIV_HOTBACKUP && (!HAVE_ATOMIC_BUILTINS || UNIV_WORD_SIZE < 8) */
-
-/** Number of pending os_file_pread() operations */
-UNIV_INTERN ulint	os_file_n_pending_preads  = 0;
-/** Number of pending os_file_pwrite() operations */
-UNIV_INTERN ulint	os_file_n_pending_pwrites = 0;
-/** Number of pending write operations */
-UNIV_INTERN ulint	os_n_pending_writes = 0;
-/** Number of pending read operations */
-UNIV_INTERN ulint	os_n_pending_reads = 0;
-
 #ifdef UNIV_DEBUG
 # ifndef UNIV_HOTBACKUP
 /**********************************************************************//**
@@ -887,10 +872,6 @@ void
 os_io_init_simple(void)
 /*===================*/
 {
-#if !defined(HAVE_ATOMIC_BUILTINS) || UNIV_WORD_SIZE < 8
-	os_file_count_mutex = os_mutex_create();
-#endif /* !HAVE_ATOMIC_BUILTINS || UNIV_WORD_SIZE < 8 */
-
 	for (ulint i = 0; i < OS_FILE_N_SEEK_MUTEXES; i++) {
 		os_file_seek_mutexes[i] = os_mutex_create();
 	}
@@ -2580,10 +2561,6 @@ os_file_pread(
 	trx_t*		trx)
 {
 	off_t	offs;
-#if defined(HAVE_PREAD) && !defined(HAVE_BROKEN_PREAD)
-	ssize_t	n_bytes;
-	ssize_t n_read;
-#endif /* HAVE_PREAD && !HAVE_BROKEN_PREAD */
 	ulint		sec;
 	ulint		ms;
 	ib_uint64_t	start_time;
@@ -2613,22 +2590,16 @@ os_file_pread(
 	} else {
 		start_time = 0;
 	}
-#if defined(HAVE_PREAD) && !defined(HAVE_BROKEN_PREAD)
-#if defined(HAVE_ATOMIC_BUILTINS) && UNIV_WORD_SIZE == 8
-	(void) os_atomic_increment_ulint(&os_n_pending_reads, 1);
-	(void) os_atomic_increment_ulint(&os_file_n_pending_preads, 1);
-	MONITOR_ATOMIC_INC(MONITOR_OS_PENDING_READS);
-#else
-	os_mutex_enter(os_file_count_mutex);
-	os_file_n_pending_preads++;
-	os_n_pending_reads++;
-	MONITOR_INC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
-#endif /* HAVE_ATOMIC_BUILTINS && UNIV_WORD == 8 */
+
+	const bool monitor = MONITOR_IS_ON(MONITOR_OS_PENDING_READS);
+#ifdef HAVE_PREAD
+	MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_READS, monitor);
+
+	ssize_t	n_bytes;
 
 	/* Handle partial reads and signal interruptions correctly */
 	for (n_bytes = 0; n_bytes < (ssize_t) n; ) {
-		n_read = pread(file, buf, (ssize_t)n - n_bytes, offs);
+		ssize_t n_read = pread(file, buf, (ssize_t)n - n_bytes, offs);
 		if (n_read > 0) {
 			n_bytes += n_read;
 			offs += n_read;
@@ -2640,17 +2611,7 @@ os_file_pread(
 		}
 	}
 
-#if defined(HAVE_ATOMIC_BUILTINS) && UNIV_WORD_SIZE == 8
-	(void) os_atomic_decrement_ulint(&os_n_pending_reads, 1);
-	(void) os_atomic_decrement_ulint(&os_file_n_pending_preads, 1);
-	MONITOR_ATOMIC_DEC(MONITOR_OS_PENDING_READS);
-#else
-	os_mutex_enter(os_file_count_mutex);
-	os_file_n_pending_preads--;
-	os_n_pending_reads--;
-	MONITOR_DEC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
-#endif /* !HAVE_ATOMIC_BUILTINS || UNIV_WORD == 8 */
+	MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 	if (UNIV_UNLIKELY(start_time != 0))
 	{
@@ -2669,15 +2630,7 @@ os_file_pread(
 		ulint	i;
 #endif /* !UNIV_HOTBACKUP */
 
-#if defined(HAVE_ATOMIC_BUILTINS) && UNIV_WORD_SIZE == 8
-		(void) os_atomic_increment_ulint(&os_n_pending_reads, 1);
-		MONITOR_ATOMIC_INC(MONITOR_OS_PENDING_READS);
-#else
-		os_mutex_enter(os_file_count_mutex);
-		os_n_pending_reads++;
-		MONITOR_INC(MONITOR_OS_PENDING_READS);
-		os_mutex_exit(os_file_count_mutex);
-#endif /* HAVE_ATOMIC_BUILTINS && UNIV_WORD == 8 */
+		MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_READS, monitor);
 #ifndef UNIV_HOTBACKUP
 		/* Protect the seek / read operation with a mutex */
 		i = ((ulint) file) % OS_FILE_N_SEEK_MUTEXES;
@@ -2707,15 +2660,7 @@ os_file_pread(
 		os_mutex_exit(os_file_seek_mutexes[i]);
 #endif /* !UNIV_HOTBACKUP */
 
-#if defined(HAVE_ATOMIC_BUILTINS) && UNIV_WORD_SIZE == 8
-		(void) os_atomic_decrement_ulint(&os_n_pending_reads, 1);
-		MONITOR_ATOIC_DEC(MONITOR_OS_PENDING_READS);
-#else
-		os_mutex_enter(os_file_count_mutex);
-		os_n_pending_reads--;
-		MONITOR_DEC(MONITOR_OS_PENDING_READS);
-		os_mutex_exit(os_file_count_mutex);
-#endif /* HAVE_ATOMIC_BUILTINS && UNIV_WORD_SIZE == 8 */
+		MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 		if (UNIV_UNLIKELY(start_time != 0)
 		{
@@ -2761,18 +2706,9 @@ os_file_pwrite(
 
 	os_n_file_writes++;
 
-#if defined(HAVE_PWRITE) && !defined(HAVE_BROKEN_PREAD)
-#if !defined(HAVE_ATOMIC_BUILTINS) || UNIV_WORD_SIZE < 8
-	os_mutex_enter(os_file_count_mutex);
-	os_file_n_pending_pwrites++;
-	os_n_pending_writes++;
-	MONITOR_INC(MONITOR_OS_PENDING_WRITES);
-	os_mutex_exit(os_file_count_mutex);
-#else
-	(void) os_atomic_increment_ulint(&os_n_pending_writes, 1);
-	(void) os_atomic_increment_ulint(&os_file_n_pending_pwrites, 1);
-	MONITOR_ATOMIC_INC(MONITOR_OS_PENDING_WRITES);
-#endif /* !HAVE_ATOMIC_BUILTINS || UNIV_WORD < 8 */
+	const bool monitor = MONITOR_IS_ON(MONITOR_OS_PENDING_WRITES);
+#ifdef HAVE_PWRITE
+	MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 
 	/* Handle partial writes and signal interruptions correctly */
 	for (ret = 0; ret < (ssize_t) n; ) {
@@ -2791,17 +2727,7 @@ os_file_pwrite(
 		}
 	}
 
-#if !defined(HAVE_ATOMIC_BUILTINS) || UNIV_WORD_SIZE < 8
-	os_mutex_enter(os_file_count_mutex);
-	os_file_n_pending_pwrites--;
-	os_n_pending_writes--;
-	MONITOR_DEC(MONITOR_OS_PENDING_WRITES);
-	os_mutex_exit(os_file_count_mutex);
-#else
-	(void) os_atomic_decrement_ulint(&os_n_pending_writes, 1);
-	(void) os_atomic_decrement_ulint(&os_file_n_pending_pwrites, 1);
-	MONITOR_ATOMIC_DEC(MONITOR_OS_PENDING_WRITES);
-#endif /* !HAVE_ATOMIC_BUILTINS || UNIV_WORD < 8 */
+	MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 
 	return(ret);
 #else
@@ -2811,10 +2737,7 @@ os_file_pwrite(
 		ulint	i;
 # endif /* !UNIV_HOTBACKUP */
 
-		os_mutex_enter(os_file_count_mutex);
-		os_n_pending_writes++;
-		MONITOR_INC(MONITOR_OS_PENDING_WRITES);
-		os_mutex_exit(os_file_count_mutex);
+		MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 
 # ifndef UNIV_HOTBACKUP
 		/* Protect the seek / write operation with a mutex */
@@ -2848,14 +2771,10 @@ func_exit:
 		os_mutex_exit(os_file_seek_mutexes[i]);
 # endif /* !UNIV_HOTBACKUP */
 
-		os_mutex_enter(os_file_count_mutex);
-		os_n_pending_writes--;
-		MONITOR_DEC(MONITOR_OS_PENDING_WRITES);
-		os_mutex_exit(os_file_count_mutex);
-
+		MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 		return(ret);
 	}
-#endif /* !UNIV_HOTBACKUP */
+#endif /* HAVE_PWRITE */
 }
 #endif
 
@@ -2887,15 +2806,13 @@ os_file_read_func(
 
 	os_n_file_reads++;
 	os_bytes_read_since_printout += n;
+	const bool monitor = MONITOR_IS_ON(MONITOR_OS_PENDING_READS);
 
 try_again:
 	ut_ad(buf);
 	ut_ad(n > 0);
 
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_reads++;
-	MONITOR_INC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 	memset (&overlapped, 0, sizeof (overlapped));
 	overlapped.Offset = (DWORD)(offset & 0xFFFFFFFF);
@@ -2908,10 +2825,7 @@ try_again:
 	else if(GetLastError() == ERROR_IO_PENDING) {
 		ret = GetOverlappedResult(file, &overlapped, (DWORD *)&len, TRUE);
         }
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_reads--;
-	MONITOR_DEC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 	if (ret && len == n) {
 		return(TRUE);
@@ -2995,15 +2909,13 @@ os_file_read_no_error_handling_func(
 
 	os_n_file_reads++;
 	os_bytes_read_since_printout += n;
+	const bool monitor = MONITOR_IS_ON(MONITOR_OS_PENDING_READS);
 
 try_again:
 	ut_ad(buf);
 	ut_ad(n > 0);
 
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_reads++;
-	MONITOR_INC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 	memset (&overlapped, 0, sizeof (overlapped));
 	overlapped.Offset = (DWORD)(offset & 0xFFFFFFFF);
@@ -3016,10 +2928,7 @@ try_again:
 	else if(GetLastError() == ERROR_IO_PENDING) {
 		ret = GetOverlappedResult(file, &overlapped, (DWORD *)&len, TRUE);
 	}
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_reads--;
-	MONITOR_DEC(MONITOR_OS_PENDING_READS);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_READS, monitor);
 
 	if (ret && len == n) {
 		return(TRUE);
@@ -3113,12 +3022,10 @@ os_file_write_func(
 
 	ut_ad(buf);
 	ut_ad(n > 0);
+	const bool monitor = MONITOR_IS_ON(MONITOR_OS_PENDING_WRITES);
 retry:
 
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_writes++;
-	MONITOR_INC(MONITOR_OS_PENDING_WRITES);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_INC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 
 	memset (&overlapped, 0, sizeof (overlapped));
 	overlapped.Offset = (DWORD)(offset & 0xFFFFFFFF);
@@ -3133,10 +3040,7 @@ retry:
 		ret = GetOverlappedResult(file, &overlapped, (DWORD *)&len, TRUE);
 	}
 
-	os_mutex_enter(os_file_count_mutex);
-	os_n_pending_writes--;
-	MONITOR_DEC(MONITOR_OS_PENDING_WRITES);
-	os_mutex_exit(os_file_count_mutex);
+	MONITOR_ATOMIC_DEC_LOW(MONITOR_OS_PENDING_WRITES, monitor);
 
 	if (ret && len == n) {
 
@@ -4230,10 +4134,6 @@ os_aio_free(void)
 		}
 	}
 
-#if !defined(HAVE_ATOMIC_BUILTINS) || UNIV_WORD_SIZE < 8
-	os_mutex_free(os_file_count_mutex);
-#endif /* !HAVE_ATOMIC_BUILTINS || UNIV_WORD_SIZE < 8 */
-
 	for (ulint i = 0; i < OS_FILE_N_SEEK_MUTEXES; i++) {
 		os_mutex_free(os_file_seek_mutexes[i]);
 	}
@@ -5909,19 +5809,24 @@ os_aio_print(
 	time_elapsed = 0.001 + difftime(current_time, os_last_printout);
 
 	fprintf(file,
-		"Pending flushes (fsync) log: %lu; buffer pool: %lu\n"
-		"%lu OS file reads, %lu OS file writes, %lu OS fsyncs\n",
-		(ulong) fil_n_pending_log_flushes,
-		(ulong) fil_n_pending_tablespace_flushes,
-		(ulong) os_n_file_reads,
-		(ulong) os_n_file_writes,
-		(ulong) os_n_fsyncs);
-
-	if (os_file_n_pending_preads != 0 || os_file_n_pending_pwrites != 0) {
+		"Pending flushes (fsync) log: " ULINTPF
+		"; buffer pool: " ULINTPF "\n"
+		ULINTPF " OS file reads, "
+		ULINTPF " OS file writes, "
+		ULINTPF " OS fsyncs\n",
+		fil_n_pending_log_flushes,
+		fil_n_pending_tablespace_flushes,
+		os_n_file_reads,
+		os_n_file_writes,
+		os_n_fsyncs);
+
+	const ulint n_reads = MONITOR_VALUE(MONITOR_OS_PENDING_READS);
+	const ulint n_writes = MONITOR_VALUE(MONITOR_OS_PENDING_WRITES);
+
+	if (n_reads != 0 || n_writes != 0) {
 		fprintf(file,
-			"%lu pending preads, %lu pending pwrites\n",
-			(ulong) os_file_n_pending_preads,
-			(ulong) os_file_n_pending_pwrites);
+			ULINTPF " pending reads, " ULINTPF " pending writes\n",
+			n_reads, n_writes);
 	}
 
 	if (os_n_file_reads == os_n_file_reads_old) {