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MDEV-6450 - MariaDB crash on Power8 when built with advance tool chain

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Part of this work is based on Stewart Smitch's memory barrier and lower priori
patches for power8.

- Added memory syncronization for innodb & xtradb for power8.
- Added HAVE_WINDOWS_MM_FENCE to CMakeList.txt
- Added os_isync to fix a syncronization problem on power
- Added log_get_lsn_nowait which is now used srv_error_monitor_thread to ensur
  if log mutex is locked.

All changes done both for InnoDB and Xtradb
This commit is contained in:
Michael Widenius 2014-08-19 19:28:35 +03:00
parent f2cbca793c
commit 5569132ffe
21 changed files with 359 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
include/my_cpu.h Normal file
View File

@ -0,0 +1,44 @@
/* Copyright (c) 2013, MariaDB foundation Ab and SkySQL
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02111-1307 USA
*/
/* instructions for specific cpu's */
/*
Macros for adjusting thread priority (hardware multi-threading)
The defines are the same ones used by the linux kernel
*/
#if defined(__powerpc__)
/* Very low priority */
#define HMT_very_low() asm volatile("or 31,31,31")
/* Low priority */
#define HMT_low() asm volatile("or 1,1,1")
/* Medium low priority */
#define HMT_medium_low() asm volatile("or 6,6,6")
/* Medium priority */
#define HMT_medium() asm volatile("or 2,2,2")
/* Medium high priority */
#define HMT_medium_high() asm volatile("or 5,5,5")
/* High priority */
#define HMT_high() asm volatile("or 3,3,3")
#else
#define HMT_very_low()
#define HMT_low()
#define HMT_medium_low()
#define HMT_medium()
#define HMT_medium_high()
#define HMT_high()
#endif

39
storage/innobase/CMakeLists.txt
View File

@ -85,12 +85,39 @@ IF(NOT CMAKE_CROSSCOMPILING)
}"
HAVE_IB_GCC_ATOMIC_BUILTINS
)
CHECK_C_SOURCE_RUNS(
"#include<stdint.h>
int main()
{
__sync_synchronize();
return(0);
}"
HAVE_IB_GCC_SYNC_SYNCHRONISE
)
CHECK_C_SOURCE_RUNS(
"#include<stdint.h>
int main()
{
__atomic_thread_fence(__ATOMIC_ACQUIRE);
__atomic_thread_fence(__ATOMIC_RELEASE);
return(0);
}"
HAVE_IB_GCC_ATOMIC_THREAD_FENCE
)
ENDIF()
IF(HAVE_IB_GCC_ATOMIC_BUILTINS)
ADD_DEFINITIONS(-DHAVE_IB_GCC_ATOMIC_BUILTINS=1)
ENDIF()
IF(HAVE_IB_GCC_SYNC_SYNCHRONISE)
ADD_DEFINITIONS(-DHAVE_IB_GCC_SYNC_SYNCHRONISE=1)
ENDIF()
IF(HAVE_IB_GCC_ATOMIC_THREAD_FENCE)
ADD_DEFINITIONS(-DHAVE_IB_GCC_ATOMIC_THREAD_FENCE=1)
ENDIF()
# either define HAVE_IB_ATOMIC_PTHREAD_T_GCC or not
IF(NOT CMAKE_CROSSCOMPILING)
CHECK_C_SOURCE_RUNS(
@ -169,10 +196,21 @@ IF(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
return(0);
}
" HAVE_IB_ATOMIC_PTHREAD_T_SOLARIS)
CHECK_C_SOURCE_COMPILES(
"#include <mbarrier.h>
int main() {
__machine_r_barrier();
__machine_w_barrier();
return(0);
}"
HAVE_IB_MACHINE_BARRIER_SOLARIS)
ENDIF()
IF(HAVE_IB_ATOMIC_PTHREAD_T_SOLARIS)
ADD_DEFINITIONS(-DHAVE_IB_ATOMIC_PTHREAD_T_SOLARIS=1)
ENDIF()
IF(HAVE_IB_MACHINE_BARRIER_SOLARIS)
ADD_DEFINITIONS(-DHAVE_IB_MACHINE_BARRIER_SOLARIS=1)
ENDIF()
ENDIF()
@ -190,6 +228,7 @@ ENDIF()
IF(MSVC)
ADD_DEFINITIONS(-DHAVE_WINDOWS_ATOMICS)
ADD_DEFINITIONS(-DHAVE_WINDOWS_MM_FENCE)
ENDIF()

7
storage/innobase/include/log0log.h
View File

@ -154,6 +154,13 @@ UNIV_INLINE
ib_uint64_t
log_get_lsn(void);
/*=============*/
/************************************************************//**
Gets the current lsn.
@return current lsn */
UNIV_INLINE
lsn_t
log_get_lsn_nowait(void);
/*=============*/
/****************************************************************
Gets the log group capacity. It is OK to read the value without
holding log_sys->mutex because it is constant.

20
storage/innobase/include/log0log.ic
View File

@ -411,6 +411,26 @@ log_get_lsn(void)
return(lsn);
}
/************************************************************//**
Gets the current lsn with a trylock
@return current lsn or 0 if false*/
UNIV_INLINE
lsn_t
log_get_lsn_nowait(void)
/*=============*/
{
lsn_t lsn;
if (mutex_enter_nowait(&(log_sys->mutex)))
return 0;
lsn = log_sys->lsn;
mutex_exit(&(log_sys->mutex));
return(lsn);
}
/****************************************************************
Gets the log group capacity. It is OK to read the value without
holding log_sys->mutex because it is constant.

48
storage/innobase/include/os0sync.h
View File

@ -416,6 +416,54 @@ clobbered */
"Mutexes and rw_locks use InnoDB's own implementation"
#endif
/** barrier definitions for memory ordering */
#ifdef HAVE_IB_GCC_ATOMIC_THREAD_FENCE
# define HAVE_MEMORY_BARRIER
# define os_rmb __atomic_thread_fence(__ATOMIC_ACQUIRE)
# define os_wmb __atomic_thread_fence(__ATOMIC_RELEASE)
#ifdef __powerpc__
# define os_isync __asm __volatile ("isync":::"memory")
#else
#define os_isync do { } while(0)
#endif
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"GCC builtin __atomic_thread_fence() is used for memory barrier"
#elif defined(HAVE_IB_GCC_SYNC_SYNCHRONISE)
# define HAVE_MEMORY_BARRIER
# define os_rmb __sync_synchronize()
# define os_wmb __sync_synchronize()
# define os_isync __sync_synchronize()
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"GCC builtin __sync_synchronize() is used for memory barrier"
#elif defined(HAVE_IB_MACHINE_BARRIER_SOLARIS)
# define HAVE_MEMORY_BARRIER
# include <mbarrier.h>
# define os_rmb __machine_r_barrier()
# define os_wmb __machine_w_barrier()
# define os_isync os_rmb; os_wmb
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"Soralis memory ordering functions are used for memory barrier"
#elif defined(HAVE_WINDOWS_MM_FENCE)
# define HAVE_MEMORY_BARRIER
# include <mmintrin.h>
# define os_rmb _mm_lfence()
# define os_wmb _mm_sfence()
# define os_isync os_rmb; os_wmb
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"_mm_lfence() and _mm_sfence() are used for memory barrier"
#else
# define os_rmb do { } while(0)
# define os_wmb do { } while(0)
# define os_isync do { } while(0)
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"Memory barrier is not used"
#endif
#ifndef UNIV_NONINL
#include "os0sync.ic"
#endif

6
storage/innobase/include/sync0rw.ic
View File

@ -200,14 +200,14 @@ rw_lock_lock_word_decr(
ulint amount) /*!< in: amount to decrement */
{
#ifdef INNODB_RW_LOCKS_USE_ATOMICS
lint local_lock_word = lock->lock_word;
while (local_lock_word > 0) {
lint local_lock_word;
os_rmb;
while ((local_lock_word= lock->lock_word) > 0) {
if (os_compare_and_swap_lint(&lock->lock_word,
local_lock_word,
local_lock_word - amount)) {
return(TRUE);
}
local_lock_word = lock->lock_word;
}
return(FALSE);
#else /* INNODB_RW_LOCKS_USE_ATOMICS */

3
storage/innobase/include/sync0sync.ic
View File

@ -92,6 +92,7 @@ mutex_test_and_set(
ut_a(mutex->lock_word == 0);
mutex->lock_word = 1;
os_wmb;
}
return((byte)ret);
@ -147,6 +148,7 @@ mutex_get_waiters(
ptr = &(mutex->waiters);
os_rmb;
return(*ptr); /* Here we assume that the read of a single
word from memory is atomic */
}
@ -181,6 +183,7 @@ mutex_exit_func(
to wake up possible hanging threads if
they are missed in mutex_signal_object. */
os_isync;
if (mutex_get_waiters(mutex) != 0) {
mutex_signal_object(mutex);

11
storage/innobase/srv/srv0srv.c
View File

@ -411,7 +411,12 @@ UNIV_INTERN ibool srv_use_checksums = TRUE;
UNIV_INTERN ulong srv_replication_delay = 0;
/*-------------------------------------------*/
#ifdef HAVE_MEMORY_BARRIER
/* No idea to wait long with memory barriers */
UNIV_INTERN ulong srv_n_spin_wait_rounds = 15;
#else
UNIV_INTERN ulong srv_n_spin_wait_rounds = 30;
#endif
UNIV_INTERN ulong srv_n_free_tickets_to_enter = 500;
UNIV_INTERN ulong srv_thread_sleep_delay = 10000;
UNIV_INTERN ulong srv_spin_wait_delay = 6;
@ -2459,9 +2464,10 @@ loop:
/* Try to track a strange bug reported by Harald Fuchs and others,
where the lsn seems to decrease at times */
new_lsn = log_get_lsn();
/* We have to use nowait to ensure we don't block */
new_lsn= log_get_lsn_nowait();
if (new_lsn < old_lsn) {
if (new_lsn && new_lsn < old_lsn) {
ut_print_timestamp(stderr);
fprintf(stderr,
" InnoDB: Error: old log sequence number %llu"
@ -2473,6 +2479,7 @@ loop:
ut_ad(0);
}
if (new_lsn)
old_lsn = new_lsn;
if (difftime(time(NULL), srv_last_monitor_time) > 60) {

3
storage/innobase/sync/sync0arr.c
View File

@ -791,6 +791,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
os_rmb;
if (lock->lock_word > 0) {
/* Either unlocked or only read locked. */
@ -802,6 +803,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
/* lock_word == 0 means all readers have left */
os_rmb;
if (lock->lock_word == 0) {
return(TRUE);
@ -810,6 +812,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
/* lock_word > 0 means no writer or reserved writer */
os_rmb;
if (lock->lock_word > 0) {
return(TRUE);

22
storage/innobase/sync/sync0rw.c
View File

@ -40,6 +40,7 @@ Created 9/11/1995 Heikki Tuuri
#include "srv0srv.h"
#include "os0sync.h" /* for INNODB_RW_LOCKS_USE_ATOMICS */
#include "ha_prototypes.h"
#include "my_cpu.h"
/*
IMPLEMENTATION OF THE RW_LOCK
@ -390,15 +391,19 @@ rw_lock_s_lock_spin(
lock_loop:
/* Spin waiting for the writer field to become free */
os_rmb;
HMT_low();
while (i < SYNC_SPIN_ROUNDS && lock->lock_word <= 0) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
i++;
os_rmb;
}
if (i == SYNC_SPIN_ROUNDS) {
HMT_medium();
if (lock->lock_word <= 0)
{
os_thread_yield();
}
@ -498,16 +503,19 @@ rw_lock_x_lock_wait(
ulint index;
ulint i = 0;
os_rmb;
ut_ad(lock->lock_word <= 0);
HMT_low();
while (lock->lock_word < 0) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
if(i < SYNC_SPIN_ROUNDS) {
i++;
os_rmb;
continue;
}
HMT_medium();
/* If there is still a reader, then go to sleep.*/
rw_x_spin_round_count += i;
@ -544,7 +552,9 @@ rw_lock_x_lock_wait(
sync_array_free_cell(sync_primary_wait_array,
index);
}
HMT_low();
}
HMT_medium();
rw_x_spin_round_count += i;
}
@ -582,6 +592,8 @@ rw_lock_x_lock_low(
file_name, line);
} else {
if (!pass)
os_rmb;
/* Decrement failed: relock or failed lock */
if (!pass && lock->recursive
&& os_thread_eq(lock->writer_thread, curr_thread)) {
@ -647,6 +659,8 @@ lock_loop:
}
/* Spin waiting for the lock_word to become free */
os_rmb;
HMT_low();
while (i < SYNC_SPIN_ROUNDS
&& lock->lock_word <= 0) {
if (srv_spin_wait_delay) {
@ -655,7 +669,9 @@ lock_loop:
}
i++;
os_rmb;
}
HMT_medium();
if (i == SYNC_SPIN_ROUNDS) {
os_thread_yield();
} else {

7
storage/innobase/sync/sync0sync.c
View File

@ -47,6 +47,7 @@ Created 9/5/1995 Heikki Tuuri
# include "srv0start.h" /* srv_is_being_started */
#endif /* UNIV_SYNC_DEBUG */
#include "ha_prototypes.h"
#include "my_cpu.h"
/*
REASONS FOR IMPLEMENTING THE SPIN LOCK MUTEX
@ -473,6 +474,8 @@ mutex_set_waiters(
ptr = &(mutex->waiters);
os_wmb;
*ptr = n; /* Here we assume that the write of a single
word in memory is atomic */
}
@ -520,13 +523,15 @@ mutex_loop:
spin_loop:
ut_d(mutex->count_spin_loop++);
HMT_low();
while (mutex_get_lock_word(mutex) != 0 && i < SYNC_SPIN_ROUNDS) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
os_rmb; // Ensure future reads sees new values
i++;
}
HMT_medium();
if (i == SYNC_SPIN_ROUNDS) {
#ifdef UNIV_DEBUG

39
storage/xtradb/CMakeLists.txt
View File

@ -117,6 +117,25 @@ IF(NOT CMAKE_CROSSCOMPILING)
}"
HAVE_IB_GCC_ATOMIC_BUILTINS_64
)
CHECK_C_SOURCE_RUNS(
"#include<stdint.h>
int main()
{
__sync_synchronize();
return(0);
}"
HAVE_IB_GCC_SYNC_SYNCHRONISE
)
CHECK_C_SOURCE_RUNS(
"#include<stdint.h>
int main()
{
__atomic_thread_fence(__ATOMIC_ACQUIRE);
__atomic_thread_fence(__ATOMIC_RELEASE);
return(0);
}"
HAVE_IB_GCC_ATOMIC_THREAD_FENCE
)
ENDIF()
IF(HAVE_IB_GCC_ATOMIC_BUILTINS)
@ -127,6 +146,14 @@ IF(HAVE_IB_GCC_ATOMIC_BUILTINS_64)
ADD_DEFINITIONS(-DHAVE_IB_GCC_ATOMIC_BUILTINS_64=1)
ENDIF()
IF(HAVE_IB_GCC_SYNC_SYNCHRONISE)
ADD_DEFINITIONS(-DHAVE_IB_GCC_SYNC_SYNCHRONISE=1)
ENDIF()
IF(HAVE_IB_GCC_ATOMIC_THREAD_FENCE)
ADD_DEFINITIONS(-DHAVE_IB_GCC_ATOMIC_THREAD_FENCE=1)
ENDIF()
# either define HAVE_IB_ATOMIC_PTHREAD_T_GCC or not
IF(NOT CMAKE_CROSSCOMPILING)
CHECK_C_SOURCE_RUNS(
@ -205,10 +232,21 @@ IF(CMAKE_SYSTEM_NAME STREQUAL "SunOS")
return(0);
}
" HAVE_IB_ATOMIC_PTHREAD_T_SOLARIS)
CHECK_C_SOURCE_COMPILES(
"#include <mbarrier.h>
int main() {
__machine_r_barrier();
__machine_w_barrier();
return(0);
}"
HAVE_IB_MACHINE_BARRIER_SOLARIS)
ENDIF()
IF(HAVE_IB_ATOMIC_PTHREAD_T_SOLARIS)
ADD_DEFINITIONS(-DHAVE_IB_ATOMIC_PTHREAD_T_SOLARIS=1)
ENDIF()
IF(HAVE_IB_MACHINE_BARRIER_SOLARIS)
ADD_DEFINITIONS(-DHAVE_IB_MACHINE_BARRIER_SOLARIS=1)
ENDIF()
ENDIF()
@ -226,6 +264,7 @@ ENDIF()
IF(MSVC)
ADD_DEFINITIONS(-DHAVE_WINDOWS_ATOMICS)
ADD_DEFINITIONS(-DHAVE_WINDOWS_MM_FENCE)
# Avoid "unreferenced label" warning in generated file
GET_FILENAME_COMPONENT(_SRC_DIR ${CMAKE_CURRENT_LIST_FILE} PATH)

7
storage/xtradb/include/log0log.h
View File

@ -162,6 +162,13 @@ UNIV_INLINE
ib_uint64_t
log_get_lsn(void);
/*=============*/
/************************************************************//**
Gets the current lsn.
@return current lsn */
UNIV_INLINE
lsn_t
log_get_lsn_nowait(void);
/*=============*/
/****************************************************************
Gets the log group capacity. It is OK to read the value without
holding log_sys->mutex because it is constant.

20
storage/xtradb/include/log0log.ic
View File

@ -426,6 +426,26 @@ log_get_lsn(void)
return(lsn);
}
/************************************************************//**
Gets the current lsn with a trylock
@return current lsn or 0 if false*/
UNIV_INLINE
lsn_t
log_get_lsn_nowait(void)
/*=============*/
{
lsn_t lsn;
if (mutex_enter_nowait(&(log_sys->mutex)))
return 0;
lsn = log_sys->lsn;
mutex_exit(&(log_sys->mutex));
return(lsn);
}
/****************************************************************
Gets the log group capacity. It is OK to read the value without
holding log_sys->mutex because it is constant.

48
storage/xtradb/include/os0sync.h
View File

@ -436,6 +436,54 @@ clobbered */
"Mutexes and rw_locks use InnoDB's own implementation"
#endif
/** barrier definitions for memory ordering */
#ifdef HAVE_IB_GCC_ATOMIC_THREAD_FENCE
# define HAVE_MEMORY_BARRIER
# define os_rmb __atomic_thread_fence(__ATOMIC_ACQUIRE)
# define os_wmb __atomic_thread_fence(__ATOMIC_RELEASE)
#ifdef __powerpc__
# define os_isync __asm __volatile ("isync":::"memory")
#else
#define os_isync do { } while(0)
#endif
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"GCC builtin __atomic_thread_fence() is used for memory barrier"
#elif defined(HAVE_IB_GCC_SYNC_SYNCHRONISE)
# define HAVE_MEMORY_BARRIER
# define os_rmb __sync_synchronize()
# define os_wmb __sync_synchronize()
# define os_isync __sync_synchronize()
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"GCC builtin __sync_synchronize() is used for memory barrier"
#elif defined(HAVE_IB_MACHINE_BARRIER_SOLARIS)
# define HAVE_MEMORY_BARRIER
# include <mbarrier.h>
# define os_rmb __machine_r_barrier()
# define os_wmb __machine_w_barrier()
# define os_isync os_rmb; os_wmb
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"Soralis memory ordering functions are used for memory barrier"
#elif defined(HAVE_WINDOWS_MM_FENCE)
# define HAVE_MEMORY_BARRIER
# include <mmintrin.h>
# define os_rmb _mm_lfence()
# define os_wmb _mm_sfence()
# define os_isync os_rmb; os_wmb
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"_mm_lfence() and _mm_sfence() are used for memory barrier"
#else
# define os_rmb do { } while(0)
# define os_wmb do { } while(0)
# define os_isync do { } while(0)
# define IB_MEMORY_BARRIER_STARTUP_MSG \
"Memory barrier is not used"
#endif
#ifndef UNIV_NONINL
#include "os0sync.ic"
#endif

6
storage/xtradb/include/sync0rw.ic
View File

@ -200,14 +200,14 @@ rw_lock_lock_word_decr(
ulint amount) /*!< in: amount to decrement */
{
#ifdef INNODB_RW_LOCKS_USE_ATOMICS
lint local_lock_word = lock->lock_word;
while (local_lock_word > 0) {
lint local_lock_word;
os_rmb;
while ((local_lock_word= lock->lock_word) > 0) {
if (os_compare_and_swap_lint(&lock->lock_word,
local_lock_word,
local_lock_word - amount)) {
return(TRUE);
}
local_lock_word = lock->lock_word;
}
return(FALSE);
#else /* INNODB_RW_LOCKS_USE_ATOMICS */

3
storage/xtradb/include/sync0sync.ic
View File

@ -92,6 +92,7 @@ mutex_test_and_set(
ut_a(mutex->lock_word == 0);
mutex->lock_word = 1;
os_wmb;
}
return((byte)ret);
@ -147,6 +148,7 @@ mutex_get_waiters(
ptr = &(mutex->waiters);
os_rmb;
return(*ptr); /* Here we assume that the read of a single
word from memory is atomic */
}
@ -181,6 +183,7 @@ mutex_exit_func(
to wake up possible hanging threads if
they are missed in mutex_signal_object. */
os_isync;
if (mutex_get_waiters(mutex) != 0) {
mutex_signal_object(mutex);

11
storage/xtradb/srv/srv0srv.c
View File

@ -440,7 +440,12 @@ UNIV_INTERN ulong srv_pass_corrupt_table = 0; /* 0:disable 1:enable */
UNIV_INTERN ulint srv_dict_size_limit = 0;
/*-------------------------------------------*/
#ifdef HAVE_MEMORY_BARRIER
/* No idea to wait long with memory barriers */
UNIV_INTERN ulong srv_n_spin_wait_rounds = 15;
#else
UNIV_INTERN ulong srv_n_spin_wait_rounds = 30;
#endif
UNIV_INTERN ulong srv_n_free_tickets_to_enter = 500;
UNIV_INTERN ulong srv_thread_sleep_delay = 10000;
UNIV_INTERN ulong srv_spin_wait_delay = 6;
@ -2929,9 +2934,10 @@ loop:
/* Try to track a strange bug reported by Harald Fuchs and others,
where the lsn seems to decrease at times */
new_lsn = log_get_lsn();
/* We have to use nowait to ensure we don't block */
new_lsn= log_get_lsn_nowait();
if (new_lsn < old_lsn) {
if (new_lsn && new_lsn < old_lsn) {
ut_print_timestamp(stderr);
fprintf(stderr,
" InnoDB: Error: old log sequence number %llu"
@ -2943,6 +2949,7 @@ loop:
ut_ad(0);
}
if (new_lsn)
old_lsn = new_lsn;
if (difftime(time(NULL), srv_last_monitor_time) > 60) {

3
storage/xtradb/sync/sync0arr.c
View File

@ -815,6 +815,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
os_rmb;
if (lock->lock_word > 0) {
/* Either unlocked or only read locked. */
@ -826,6 +827,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
/* lock_word == 0 means all readers have left */
os_rmb;
if (lock->lock_word == 0) {
return(TRUE);
@ -834,6 +836,7 @@ sync_arr_cell_can_wake_up(
lock = cell->wait_object;
/* lock_word > 0 means no writer or reserved writer */
os_rmb;
if (lock->lock_word > 0) {
return(TRUE);

20
storage/xtradb/sync/sync0rw.c
View File

@ -40,6 +40,7 @@ Created 9/11/1995 Heikki Tuuri
#include "srv0srv.h"
#include "os0sync.h" /* for INNODB_RW_LOCKS_USE_ATOMICS */
#include "ha_prototypes.h"
#include "my_cpu.h"
/*
IMPLEMENTATION OF THE RW_LOCK
@ -390,15 +391,19 @@ rw_lock_s_lock_spin(
lock_loop:
/* Spin waiting for the writer field to become free */
os_rmb;
HMT_low();
while (i < SYNC_SPIN_ROUNDS && lock->lock_word <= 0) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
i++;
os_rmb;
}
if (i == SYNC_SPIN_ROUNDS) {
HMT_medium();
if (lock->lock_word <= 0) {
os_thread_yield();
}
@ -495,16 +500,19 @@ rw_lock_x_lock_wait(
ulint index;
ulint i = 0;
os_rmb;
ut_ad(lock->lock_word <= 0);
HMT_low();
while (lock->lock_word < 0) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
if(i < SYNC_SPIN_ROUNDS) {
i++;
os_rmb;
continue;
}
HMT_medium();
/* If there is still a reader, then go to sleep.*/
rw_x_spin_round_count += i;
@ -541,7 +549,9 @@ rw_lock_x_lock_wait(
sync_array_free_cell(sync_primary_wait_array,
index);
}
HMT_low();
}
HMT_medium();
rw_x_spin_round_count += i;
}
@ -579,6 +589,8 @@ rw_lock_x_lock_low(
file_name, line);
} else {
if (!pass)
os_rmb;
/* Decrement failed: relock or failed lock */
if (!pass && lock->recursive
&& os_thread_eq(lock->writer_thread, curr_thread)) {
@ -644,6 +656,8 @@ lock_loop:
}
/* Spin waiting for the lock_word to become free */
os_rmb;
HMT_low();
while (i < SYNC_SPIN_ROUNDS
&& lock->lock_word <= 0) {
if (srv_spin_wait_delay) {
@ -652,7 +666,9 @@ lock_loop:
}
i++;
os_rmb;
}
HMT_medium();
if (i == SYNC_SPIN_ROUNDS) {
os_thread_yield();
} else {

7
storage/xtradb/sync/sync0sync.c
View File

@ -44,6 +44,7 @@ Created 9/5/1995 Heikki Tuuri
# include "srv0start.h" /* srv_is_being_started */
#endif /* UNIV_SYNC_DEBUG */
#include "ha_prototypes.h"
#include "my_cpu.h"
/*
REASONS FOR IMPLEMENTING THE SPIN LOCK MUTEX
@ -481,6 +482,8 @@ mutex_set_waiters(
ptr = &(mutex->waiters);
os_wmb;
*ptr = n; /* Here we assume that the write of a single
word in memory is atomic */
#endif
@ -523,13 +526,15 @@ mutex_loop:
spin_loop:
ut_d(mutex->count_spin_loop++);
HMT_low();
while (mutex_get_lock_word(mutex) != 0 && i < SYNC_SPIN_ROUNDS) {
if (srv_spin_wait_delay) {
ut_delay(ut_rnd_interval(0, srv_spin_wait_delay));
}
os_rmb; // Ensure future reads sees new values
i++;
}
HMT_medium();
if (i == SYNC_SPIN_ROUNDS) {
#ifdef UNIV_DEBUG