mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 12:02:42 +01:00
1c2a13b894
Addendum fixes after changing the condition variable for the global read lock. The stress test suite revealed some deadlocks. Some were related to the new condition variable (COND_global_read_lock) and some were general problems with the global read lock. It is now necessary to signal COND_global_read_lock whenever COND_refresh is signalled. We need to wait for the release of a global read lock if one is set before every operation that requires a write lock. But we must not wait if we have locked tables by LOCK TABLES. After setting a global read lock a thread waits until all write locks are released. mysql-test/r/lock_multi.result: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Added test results. mysql-test/t/lock_multi.test: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Added tests for possible deadlocks that did not occur with the stress test suite. mysys/thr_lock.c: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Added a protection against an infinite loop that occurs with the test case for Bug #20662. sql/lock.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Signal COND_global_read_lock whenever COND_refresh is signalled by using the new function broadcast_refresh(). Added the definition of a new function that signals COND_global_read_lock whenever COND_refresh is signalled. sql/mysql_priv.h: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Added a declaration for a new function that signals COND_global_read_lock whenever COND_refresh is signalled. sql/sql_base.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Signal COND_global_read_lock whenever COND_refresh is signalled by using the new function broadcast_refresh(). sql/sql_handler.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Signal COND_global_read_lock whenever COND_refresh is signalled by using the new function broadcast_refresh(). sql/sql_insert.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Removed global read lock handling from inside of INSERT DELAYED. It is handled on a higher level now. sql/sql_parse.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Wait for the release of a global read lock if one is set before every operation that requires a write lock. But don't wait if locked tables exist already. sql/sql_table.cc: Bug#16986 - Deadlock condition with MyISAM tables Addendum fixes after changing the condition variable for the global read lock. Removed global read lock handling from inside of CREATE TABLE. It is handled on a higher level now. Signal COND_global_read_lock whenever COND_refresh is signalled by using the new function broadcast_refresh().
1485 lines
44 KiB
C
1485 lines
44 KiB
C
/* Copyright (C) 2000 MySQL AB
|
|
|
|
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; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
|
|
|
|
/*
|
|
Read and write locks for Posix threads. All tread must acquire
|
|
all locks it needs through thr_multi_lock() to avoid dead-locks.
|
|
A lock consists of a master lock (THR_LOCK), and lock instances
|
|
(THR_LOCK_DATA).
|
|
Any thread can have any number of lock instances (read and write:s) on
|
|
any lock. All lock instances must be freed.
|
|
Locks are prioritized according to:
|
|
|
|
The current lock types are:
|
|
|
|
TL_READ # Low priority read
|
|
TL_READ_WITH_SHARED_LOCKS
|
|
TL_READ_HIGH_PRIORITY # High priority read
|
|
TL_READ_NO_INSERT # Read without concurrent inserts
|
|
TL_WRITE_ALLOW_WRITE # Write lock that allows other writers
|
|
TL_WRITE_ALLOW_READ # Write lock, but allow reading
|
|
TL_WRITE_CONCURRENT_INSERT
|
|
# Insert that can be mixed when selects
|
|
TL_WRITE_DELAYED # Used by delayed insert
|
|
# Allows lower locks to take over
|
|
TL_WRITE_LOW_PRIORITY # Low priority write
|
|
TL_WRITE # High priority write
|
|
TL_WRITE_ONLY # High priority write
|
|
# Abort all new lock request with an error
|
|
|
|
Locks are prioritized according to:
|
|
|
|
WRITE_ALLOW_WRITE, WRITE_ALLOW_READ, WRITE_CONCURRENT_INSERT, WRITE_DELAYED,
|
|
WRITE_LOW_PRIORITY, READ, WRITE, READ_HIGH_PRIORITY and WRITE_ONLY
|
|
|
|
Locks in the same privilege level are scheduled in first-in-first-out order.
|
|
|
|
To allow concurrent read/writes locks, with 'WRITE_CONCURRENT_INSERT' one
|
|
should put a pointer to the following functions in the lock structure:
|
|
(If the pointer is zero (default), the function is not called)
|
|
|
|
check_status:
|
|
Before giving a lock of type TL_WRITE_CONCURRENT_INSERT,
|
|
we check if this function exists and returns 0.
|
|
If not, then the lock is upgraded to TL_WRITE_LOCK
|
|
In MyISAM this is a simple check if the insert can be done
|
|
at the end of the datafile.
|
|
update_status:
|
|
Before a write lock is released, this function is called.
|
|
In MyISAM this functions updates the count and length of the datafile
|
|
get_status:
|
|
When one gets a lock this functions is called.
|
|
In MyISAM this stores the number of rows and size of the datafile
|
|
for concurrent reads.
|
|
|
|
The lock algorithm allows one to have one TL_WRITE_ALLOW_READ,
|
|
TL_WRITE_CONCURRENT_INSERT or one TL_WRITE_DELAYED lock at the same time as
|
|
multiple read locks.
|
|
|
|
*/
|
|
|
|
#if !defined(MAIN) && !defined(DBUG_OFF) && !defined(EXTRA_DEBUG)
|
|
#define DBUG_OFF
|
|
#endif
|
|
|
|
#include "mysys_priv.h"
|
|
|
|
#ifdef THREAD
|
|
#include "thr_lock.h"
|
|
#include <m_string.h>
|
|
#include <errno.h>
|
|
|
|
my_bool thr_lock_inited=0;
|
|
ulong locks_immediate = 0L, locks_waited = 0L;
|
|
ulong table_lock_wait_timeout;
|
|
enum thr_lock_type thr_upgraded_concurrent_insert_lock = TL_WRITE;
|
|
|
|
/* The following constants are only for debug output */
|
|
#define MAX_THREADS 100
|
|
#define MAX_LOCKS 100
|
|
|
|
|
|
LIST *thr_lock_thread_list; /* List of threads in use */
|
|
ulong max_write_lock_count= ~(ulong) 0L;
|
|
|
|
static inline pthread_cond_t *get_cond(void)
|
|
{
|
|
return &my_thread_var->suspend;
|
|
}
|
|
|
|
/*
|
|
** For the future (now the thread specific cond is alloced by my_pthread.c)
|
|
*/
|
|
|
|
my_bool init_thr_lock()
|
|
{
|
|
thr_lock_inited=1;
|
|
return 0;
|
|
}
|
|
|
|
static inline my_bool
|
|
thr_lock_owner_equal(THR_LOCK_OWNER *rhs, THR_LOCK_OWNER *lhs)
|
|
{
|
|
return rhs == lhs;
|
|
}
|
|
|
|
|
|
#ifdef EXTRA_DEBUG
|
|
#define MAX_FOUND_ERRORS 10 /* Report 10 first errors */
|
|
static uint found_errors=0;
|
|
|
|
static int check_lock(struct st_lock_list *list, const char* lock_type,
|
|
const char *where, my_bool same_owner, bool no_cond)
|
|
{
|
|
THR_LOCK_DATA *data,**prev;
|
|
uint count=0;
|
|
THR_LOCK_OWNER *first_owner;
|
|
LINT_INIT(first_owner);
|
|
|
|
prev= &list->data;
|
|
if (list->data)
|
|
{
|
|
enum thr_lock_type last_lock_type=list->data->type;
|
|
|
|
if (same_owner && list->data)
|
|
first_owner= list->data->owner;
|
|
for (data=list->data; data && count++ < MAX_LOCKS ; data=data->next)
|
|
{
|
|
if (data->type != last_lock_type)
|
|
last_lock_type=TL_IGNORE;
|
|
if (data->prev != prev)
|
|
{
|
|
fprintf(stderr,
|
|
"Warning: prev link %d didn't point at previous lock at %s: %s\n",
|
|
count, lock_type, where);
|
|
return 1;
|
|
}
|
|
if (same_owner &&
|
|
!thr_lock_owner_equal(data->owner, first_owner) &&
|
|
last_lock_type != TL_WRITE_ALLOW_WRITE)
|
|
{
|
|
fprintf(stderr,
|
|
"Warning: Found locks from different threads in %s: %s\n",
|
|
lock_type,where);
|
|
return 1;
|
|
}
|
|
if (no_cond && data->cond)
|
|
{
|
|
fprintf(stderr,
|
|
"Warning: Found active lock with not reset cond %s: %s\n",
|
|
lock_type,where);
|
|
return 1;
|
|
}
|
|
prev= &data->next;
|
|
}
|
|
if (data)
|
|
{
|
|
fprintf(stderr,"Warning: found too many locks at %s: %s\n",
|
|
lock_type,where);
|
|
return 1;
|
|
}
|
|
}
|
|
if (prev != list->last)
|
|
{
|
|
fprintf(stderr,"Warning: last didn't point at last lock at %s: %s\n",
|
|
lock_type, where);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void check_locks(THR_LOCK *lock, const char *where,
|
|
my_bool allow_no_locks)
|
|
{
|
|
uint old_found_errors=found_errors;
|
|
DBUG_ENTER("check_locks");
|
|
|
|
if (found_errors < MAX_FOUND_ERRORS)
|
|
{
|
|
if (check_lock(&lock->write,"write",where,1,1) |
|
|
check_lock(&lock->write_wait,"write_wait",where,0,0) |
|
|
check_lock(&lock->read,"read",where,0,1) |
|
|
check_lock(&lock->read_wait,"read_wait",where,0,0))
|
|
found_errors++;
|
|
|
|
if (found_errors < MAX_FOUND_ERRORS)
|
|
{
|
|
uint count=0;
|
|
THR_LOCK_DATA *data;
|
|
for (data=lock->read.data ; data ; data=data->next)
|
|
{
|
|
if ((int) data->type == (int) TL_READ_NO_INSERT)
|
|
count++;
|
|
/* Protect against infinite loop. */
|
|
DBUG_ASSERT(count <= lock->read_no_write_count);
|
|
}
|
|
if (count != lock->read_no_write_count)
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': Locks read_no_write_count was %u when it should have been %u\n", where, lock->read_no_write_count,count);
|
|
}
|
|
|
|
if (!lock->write.data)
|
|
{
|
|
if (!allow_no_locks && !lock->read.data &&
|
|
(lock->write_wait.data || lock->read_wait.data))
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': No locks in use but locks are in wait queue\n",
|
|
where);
|
|
}
|
|
if (!lock->write_wait.data)
|
|
{
|
|
if (!allow_no_locks && lock->read_wait.data)
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': No write locks and waiting read locks\n",
|
|
where);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if (!allow_no_locks &&
|
|
(((lock->write_wait.data->type == TL_WRITE_CONCURRENT_INSERT ||
|
|
lock->write_wait.data->type == TL_WRITE_ALLOW_WRITE) &&
|
|
!lock->read_no_write_count) ||
|
|
lock->write_wait.data->type == TL_WRITE_ALLOW_READ ||
|
|
(lock->write_wait.data->type == TL_WRITE_DELAYED &&
|
|
!lock->read.data)))
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': Write lock %d waiting while no exclusive read locks\n",where,(int) lock->write_wait.data->type);
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{ /* Have write lock */
|
|
if (lock->write_wait.data)
|
|
{
|
|
if (!allow_no_locks &&
|
|
lock->write.data->type == TL_WRITE_ALLOW_WRITE &&
|
|
lock->write_wait.data->type == TL_WRITE_ALLOW_WRITE)
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': Found WRITE_ALLOW_WRITE lock waiting for WRITE_ALLOW_WRITE lock\n",
|
|
where);
|
|
}
|
|
}
|
|
if (lock->read.data)
|
|
{
|
|
if (!thr_lock_owner_equal(lock->write.data->owner,
|
|
lock->read.data->owner) &&
|
|
((lock->write.data->type > TL_WRITE_DELAYED &&
|
|
lock->write.data->type != TL_WRITE_ONLY) ||
|
|
((lock->write.data->type == TL_WRITE_CONCURRENT_INSERT ||
|
|
lock->write.data->type == TL_WRITE_ALLOW_WRITE) &&
|
|
lock->read_no_write_count)))
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': Found lock of type %d that is write and read locked\n",
|
|
where, lock->write.data->type);
|
|
DBUG_PRINT("warning",("At '%s': Found lock of type %d that is write and read locked\n",
|
|
where, lock->write.data->type));
|
|
|
|
}
|
|
}
|
|
if (lock->read_wait.data)
|
|
{
|
|
if (!allow_no_locks && lock->write.data->type <= TL_WRITE_DELAYED &&
|
|
lock->read_wait.data->type <= TL_READ_HIGH_PRIORITY)
|
|
{
|
|
found_errors++;
|
|
fprintf(stderr,
|
|
"Warning at '%s': Found read lock of type %d waiting for write lock of type %d\n",
|
|
where,
|
|
(int) lock->read_wait.data->type,
|
|
(int) lock->write.data->type);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (found_errors != old_found_errors)
|
|
{
|
|
DBUG_PRINT("error",("Found wrong lock"));
|
|
}
|
|
}
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
#else /* EXTRA_DEBUG */
|
|
#define check_locks(A,B,C)
|
|
#endif
|
|
|
|
|
|
/* Initialize a lock */
|
|
|
|
void thr_lock_init(THR_LOCK *lock)
|
|
{
|
|
DBUG_ENTER("thr_lock_init");
|
|
bzero((char*) lock,sizeof(*lock));
|
|
VOID(pthread_mutex_init(&lock->mutex,MY_MUTEX_INIT_FAST));
|
|
lock->read.last= &lock->read.data;
|
|
lock->read_wait.last= &lock->read_wait.data;
|
|
lock->write_wait.last= &lock->write_wait.data;
|
|
lock->write.last= &lock->write.data;
|
|
|
|
pthread_mutex_lock(&THR_LOCK_lock); /* Add to locks in use */
|
|
lock->list.data=(void*) lock;
|
|
thr_lock_thread_list=list_add(thr_lock_thread_list,&lock->list);
|
|
pthread_mutex_unlock(&THR_LOCK_lock);
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
|
|
void thr_lock_delete(THR_LOCK *lock)
|
|
{
|
|
DBUG_ENTER("thr_lock_delete");
|
|
VOID(pthread_mutex_destroy(&lock->mutex));
|
|
pthread_mutex_lock(&THR_LOCK_lock);
|
|
thr_lock_thread_list=list_delete(thr_lock_thread_list,&lock->list);
|
|
pthread_mutex_unlock(&THR_LOCK_lock);
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
|
|
void thr_lock_info_init(THR_LOCK_INFO *info)
|
|
{
|
|
info->thread= pthread_self();
|
|
info->thread_id= my_thread_id(); /* for debugging */
|
|
info->n_cursors= 0;
|
|
}
|
|
|
|
/* Initialize a lock instance */
|
|
|
|
void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data, void *param)
|
|
{
|
|
data->lock=lock;
|
|
data->type=TL_UNLOCK;
|
|
data->owner= 0; /* no owner yet */
|
|
data->status_param=param;
|
|
data->cond=0;
|
|
}
|
|
|
|
|
|
static inline my_bool
|
|
have_old_read_lock(THR_LOCK_DATA *data, THR_LOCK_OWNER *owner)
|
|
{
|
|
for ( ; data ; data=data->next)
|
|
{
|
|
if (thr_lock_owner_equal(data->owner, owner))
|
|
return 1; /* Already locked by thread */
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline my_bool have_specific_lock(THR_LOCK_DATA *data,
|
|
enum thr_lock_type type)
|
|
{
|
|
for ( ; data ; data=data->next)
|
|
{
|
|
if (data->type == type)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
static enum enum_thr_lock_result
|
|
wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
|
|
my_bool in_wait_list)
|
|
{
|
|
struct st_my_thread_var *thread_var= my_thread_var;
|
|
pthread_cond_t *cond= &thread_var->suspend;
|
|
struct timespec wait_timeout;
|
|
enum enum_thr_lock_result result= THR_LOCK_ABORTED;
|
|
my_bool can_deadlock= test(data->owner->info->n_cursors);
|
|
|
|
if (!in_wait_list)
|
|
{
|
|
(*wait->last)=data; /* Wait for lock */
|
|
data->prev= wait->last;
|
|
wait->last= &data->next;
|
|
}
|
|
|
|
/* Set up control struct to allow others to abort locks */
|
|
thread_var->current_mutex= &data->lock->mutex;
|
|
thread_var->current_cond= cond;
|
|
data->cond= cond;
|
|
|
|
if (can_deadlock)
|
|
set_timespec(wait_timeout, table_lock_wait_timeout);
|
|
while (!thread_var->abort || in_wait_list)
|
|
{
|
|
int rc= (can_deadlock ?
|
|
pthread_cond_timedwait(cond, &data->lock->mutex,
|
|
&wait_timeout) :
|
|
pthread_cond_wait(cond, &data->lock->mutex));
|
|
/*
|
|
We must break the wait if one of the following occurs:
|
|
- the connection has been aborted (!thread_var->abort), but
|
|
this is not a delayed insert thread (in_wait_list). For a delayed
|
|
insert thread the proper action at shutdown is, apparently, to
|
|
acquire the lock and complete the insert.
|
|
- the lock has been granted (data->cond is set to NULL by the granter),
|
|
or the waiting has been aborted (additionally data->type is set to
|
|
TL_UNLOCK).
|
|
- the wait has timed out (rc == ETIMEDOUT)
|
|
Order of checks below is important to not report about timeout
|
|
if the predicate is true.
|
|
*/
|
|
if (data->cond == 0)
|
|
break;
|
|
if (rc == ETIMEDOUT || rc == ETIME)
|
|
{
|
|
result= THR_LOCK_WAIT_TIMEOUT;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (data->cond || data->type == TL_UNLOCK)
|
|
{
|
|
if (data->cond) /* aborted or timed out */
|
|
{
|
|
if (((*data->prev)=data->next)) /* remove from wait-list */
|
|
data->next->prev= data->prev;
|
|
else
|
|
wait->last=data->prev;
|
|
data->type= TL_UNLOCK; /* No lock */
|
|
}
|
|
check_locks(data->lock,"failed wait_for_lock",0);
|
|
}
|
|
else
|
|
{
|
|
result= THR_LOCK_SUCCESS;
|
|
statistic_increment(locks_waited, &THR_LOCK_lock);
|
|
if (data->lock->get_status)
|
|
(*data->lock->get_status)(data->status_param, 0);
|
|
check_locks(data->lock,"got wait_for_lock",0);
|
|
}
|
|
pthread_mutex_unlock(&data->lock->mutex);
|
|
|
|
/* The following must be done after unlock of lock->mutex */
|
|
pthread_mutex_lock(&thread_var->mutex);
|
|
thread_var->current_mutex= 0;
|
|
thread_var->current_cond= 0;
|
|
pthread_mutex_unlock(&thread_var->mutex);
|
|
return result;
|
|
}
|
|
|
|
|
|
enum enum_thr_lock_result
|
|
thr_lock(THR_LOCK_DATA *data, THR_LOCK_OWNER *owner,
|
|
enum thr_lock_type lock_type)
|
|
{
|
|
THR_LOCK *lock=data->lock;
|
|
enum enum_thr_lock_result result= THR_LOCK_SUCCESS;
|
|
struct st_lock_list *wait_queue;
|
|
THR_LOCK_DATA *lock_owner;
|
|
DBUG_ENTER("thr_lock");
|
|
|
|
data->next=0;
|
|
data->cond=0; /* safety */
|
|
data->type=lock_type;
|
|
data->owner= owner; /* Must be reset ! */
|
|
VOID(pthread_mutex_lock(&lock->mutex));
|
|
DBUG_PRINT("lock",("data: 0x%lx thread: %ld lock: 0x%lx type: %d",
|
|
data, data->owner->info->thread_id,
|
|
lock, (int) lock_type));
|
|
check_locks(lock,(uint) lock_type <= (uint) TL_READ_NO_INSERT ?
|
|
"enter read_lock" : "enter write_lock",0);
|
|
if ((int) lock_type <= (int) TL_READ_NO_INSERT)
|
|
{
|
|
/* Request for READ lock */
|
|
if (lock->write.data)
|
|
{
|
|
/* We can allow a read lock even if there is already a write lock
|
|
on the table in one the following cases:
|
|
- This thread alread have a write lock on the table
|
|
- The write lock is TL_WRITE_ALLOW_READ or TL_WRITE_DELAYED
|
|
and the read lock is TL_READ_HIGH_PRIORITY or TL_READ
|
|
- The write lock is TL_WRITE_CONCURRENT_INSERT or TL_WRITE_ALLOW_WRITE
|
|
and the read lock is not TL_READ_NO_INSERT
|
|
*/
|
|
|
|
DBUG_PRINT("lock",("write locked by thread: %ld",
|
|
lock->write.data->owner->info->thread_id));
|
|
if (thr_lock_owner_equal(data->owner, lock->write.data->owner) ||
|
|
(lock->write.data->type <= TL_WRITE_DELAYED &&
|
|
(((int) lock_type <= (int) TL_READ_HIGH_PRIORITY) ||
|
|
(lock->write.data->type != TL_WRITE_CONCURRENT_INSERT &&
|
|
lock->write.data->type != TL_WRITE_ALLOW_READ))))
|
|
{ /* Already got a write lock */
|
|
(*lock->read.last)=data; /* Add to running FIFO */
|
|
data->prev=lock->read.last;
|
|
lock->read.last= &data->next;
|
|
if (lock_type == TL_READ_NO_INSERT)
|
|
lock->read_no_write_count++;
|
|
check_locks(lock,"read lock with old write lock",0);
|
|
if (lock->get_status)
|
|
(*lock->get_status)(data->status_param, 0);
|
|
statistic_increment(locks_immediate,&THR_LOCK_lock);
|
|
goto end;
|
|
}
|
|
if (lock->write.data->type == TL_WRITE_ONLY)
|
|
{
|
|
/* We are not allowed to get a READ lock in this case */
|
|
data->type=TL_UNLOCK;
|
|
result= THR_LOCK_ABORTED; /* Can't wait for this one */
|
|
goto end;
|
|
}
|
|
}
|
|
else if (!lock->write_wait.data ||
|
|
lock->write_wait.data->type <= TL_WRITE_LOW_PRIORITY ||
|
|
lock_type == TL_READ_HIGH_PRIORITY ||
|
|
have_old_read_lock(lock->read.data, data->owner))
|
|
{ /* No important write-locks */
|
|
(*lock->read.last)=data; /* Add to running FIFO */
|
|
data->prev=lock->read.last;
|
|
lock->read.last= &data->next;
|
|
if (lock->get_status)
|
|
(*lock->get_status)(data->status_param, 0);
|
|
if (lock_type == TL_READ_NO_INSERT)
|
|
lock->read_no_write_count++;
|
|
check_locks(lock,"read lock with no write locks",0);
|
|
statistic_increment(locks_immediate,&THR_LOCK_lock);
|
|
goto end;
|
|
}
|
|
/*
|
|
We're here if there is an active write lock or no write
|
|
lock but a high priority write waiting in the write_wait queue.
|
|
In the latter case we should yield the lock to the writer.
|
|
*/
|
|
wait_queue= &lock->read_wait;
|
|
}
|
|
else /* Request for WRITE lock */
|
|
{
|
|
if (lock_type == TL_WRITE_DELAYED)
|
|
{
|
|
if (lock->write.data && lock->write.data->type == TL_WRITE_ONLY)
|
|
{
|
|
data->type=TL_UNLOCK;
|
|
result= THR_LOCK_ABORTED; /* Can't wait for this one */
|
|
goto end;
|
|
}
|
|
/*
|
|
if there is a TL_WRITE_ALLOW_READ lock, we have to wait for a lock
|
|
(TL_WRITE_ALLOW_READ is used for ALTER TABLE in MySQL)
|
|
*/
|
|
if ((!lock->write.data ||
|
|
lock->write.data->type != TL_WRITE_ALLOW_READ) &&
|
|
!have_specific_lock(lock->write_wait.data,TL_WRITE_ALLOW_READ) &&
|
|
(lock->write.data || lock->read.data))
|
|
{
|
|
/* Add delayed write lock to write_wait queue, and return at once */
|
|
(*lock->write_wait.last)=data;
|
|
data->prev=lock->write_wait.last;
|
|
lock->write_wait.last= &data->next;
|
|
data->cond=get_cond();
|
|
/*
|
|
We don't have to do get_status here as we will do it when we change
|
|
the delayed lock to a real write lock
|
|
*/
|
|
statistic_increment(locks_immediate,&THR_LOCK_lock);
|
|
goto end;
|
|
}
|
|
}
|
|
else if (lock_type == TL_WRITE_CONCURRENT_INSERT && ! lock->check_status)
|
|
data->type=lock_type= thr_upgraded_concurrent_insert_lock;
|
|
|
|
if (lock->write.data) /* If there is a write lock */
|
|
{
|
|
if (lock->write.data->type == TL_WRITE_ONLY)
|
|
{
|
|
/* We are not allowed to get a lock in this case */
|
|
data->type=TL_UNLOCK;
|
|
result= THR_LOCK_ABORTED; /* Can't wait for this one */
|
|
goto end;
|
|
}
|
|
|
|
/*
|
|
The following test will not work if the old lock was a
|
|
TL_WRITE_ALLOW_WRITE, TL_WRITE_ALLOW_READ or TL_WRITE_DELAYED in
|
|
the same thread, but this will never happen within MySQL.
|
|
*/
|
|
if (thr_lock_owner_equal(data->owner, lock->write.data->owner) ||
|
|
(lock_type == TL_WRITE_ALLOW_WRITE &&
|
|
!lock->write_wait.data &&
|
|
lock->write.data->type == TL_WRITE_ALLOW_WRITE))
|
|
{
|
|
/*
|
|
We have already got a write lock or all locks are
|
|
TL_WRITE_ALLOW_WRITE
|
|
*/
|
|
DBUG_PRINT("info", ("write_wait.data: 0x%lx old_type: %d",
|
|
(ulong) lock->write_wait.data,
|
|
lock->write.data->type));
|
|
|
|
(*lock->write.last)=data; /* Add to running fifo */
|
|
data->prev=lock->write.last;
|
|
lock->write.last= &data->next;
|
|
check_locks(lock,"second write lock",0);
|
|
if (data->lock->get_status)
|
|
(*data->lock->get_status)(data->status_param, 0);
|
|
statistic_increment(locks_immediate,&THR_LOCK_lock);
|
|
goto end;
|
|
}
|
|
DBUG_PRINT("lock",("write locked by thread: %ld",
|
|
lock->write.data->owner->info->thread_id));
|
|
}
|
|
else
|
|
{
|
|
DBUG_PRINT("info", ("write_wait.data: 0x%lx",
|
|
(ulong) lock->write_wait.data));
|
|
if (!lock->write_wait.data)
|
|
{ /* no scheduled write locks */
|
|
my_bool concurrent_insert= 0;
|
|
if (lock_type == TL_WRITE_CONCURRENT_INSERT)
|
|
{
|
|
concurrent_insert= 1;
|
|
if ((*lock->check_status)(data->status_param))
|
|
{
|
|
concurrent_insert= 0;
|
|
data->type=lock_type= thr_upgraded_concurrent_insert_lock;
|
|
}
|
|
}
|
|
|
|
if (!lock->read.data ||
|
|
(lock_type <= TL_WRITE_DELAYED &&
|
|
((lock_type != TL_WRITE_CONCURRENT_INSERT &&
|
|
lock_type != TL_WRITE_ALLOW_WRITE) ||
|
|
!lock->read_no_write_count)))
|
|
{
|
|
(*lock->write.last)=data; /* Add as current write lock */
|
|
data->prev=lock->write.last;
|
|
lock->write.last= &data->next;
|
|
if (data->lock->get_status)
|
|
(*data->lock->get_status)(data->status_param, concurrent_insert);
|
|
check_locks(lock,"only write lock",0);
|
|
statistic_increment(locks_immediate,&THR_LOCK_lock);
|
|
goto end;
|
|
}
|
|
}
|
|
DBUG_PRINT("lock",("write locked by thread: %ld, type: %ld",
|
|
lock->read.data->owner->info->thread_id, data->type));
|
|
}
|
|
wait_queue= &lock->write_wait;
|
|
}
|
|
/*
|
|
Try to detect a trivial deadlock when using cursors: attempt to
|
|
lock a table that is already locked by an open cursor within the
|
|
same connection. lock_owner can be zero if we succumbed to a high
|
|
priority writer in the write_wait queue.
|
|
*/
|
|
lock_owner= lock->read.data ? lock->read.data : lock->write.data;
|
|
if (lock_owner && lock_owner->owner->info == owner->info)
|
|
{
|
|
result= THR_LOCK_DEADLOCK;
|
|
goto end;
|
|
}
|
|
/* Can't get lock yet; Wait for it */
|
|
DBUG_RETURN(wait_for_lock(wait_queue, data, 0));
|
|
end:
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(result);
|
|
}
|
|
|
|
|
|
static inline void free_all_read_locks(THR_LOCK *lock,
|
|
bool using_concurrent_insert)
|
|
{
|
|
THR_LOCK_DATA *data=lock->read_wait.data;
|
|
|
|
check_locks(lock,"before freeing read locks",1);
|
|
|
|
/* move all locks from read_wait list to read list */
|
|
(*lock->read.last)=data;
|
|
data->prev=lock->read.last;
|
|
lock->read.last=lock->read_wait.last;
|
|
|
|
/* Clear read_wait list */
|
|
lock->read_wait.last= &lock->read_wait.data;
|
|
|
|
do
|
|
{
|
|
pthread_cond_t *cond=data->cond;
|
|
if ((int) data->type == (int) TL_READ_NO_INSERT)
|
|
{
|
|
if (using_concurrent_insert)
|
|
{
|
|
/*
|
|
We can't free this lock;
|
|
Link lock away from read chain back into read_wait chain
|
|
*/
|
|
if (((*data->prev)=data->next))
|
|
data->next->prev=data->prev;
|
|
else
|
|
lock->read.last=data->prev;
|
|
*lock->read_wait.last= data;
|
|
data->prev= lock->read_wait.last;
|
|
lock->read_wait.last= &data->next;
|
|
continue;
|
|
}
|
|
lock->read_no_write_count++;
|
|
}
|
|
DBUG_PRINT("lock",("giving read lock to thread: %ld",
|
|
data->owner->info->thread_id));
|
|
data->cond=0; /* Mark thread free */
|
|
VOID(pthread_cond_signal(cond));
|
|
} while ((data=data->next));
|
|
*lock->read_wait.last=0;
|
|
if (!lock->read_wait.data)
|
|
lock->write_lock_count=0;
|
|
check_locks(lock,"after giving read locks",0);
|
|
}
|
|
|
|
/* Unlock lock and free next thread on same lock */
|
|
|
|
void thr_unlock(THR_LOCK_DATA *data)
|
|
{
|
|
THR_LOCK *lock=data->lock;
|
|
enum thr_lock_type lock_type=data->type;
|
|
DBUG_ENTER("thr_unlock");
|
|
DBUG_PRINT("lock",("data: 0x%lx thread: %ld lock: 0x%lx",
|
|
data, data->owner->info->thread_id, lock));
|
|
pthread_mutex_lock(&lock->mutex);
|
|
check_locks(lock,"start of release lock",0);
|
|
|
|
if (((*data->prev)=data->next)) /* remove from lock-list */
|
|
data->next->prev= data->prev;
|
|
else if (lock_type <= TL_READ_NO_INSERT)
|
|
lock->read.last=data->prev;
|
|
else if (lock_type == TL_WRITE_DELAYED && data->cond)
|
|
{
|
|
/*
|
|
This only happens in extreme circumstances when a
|
|
write delayed lock that is waiting for a lock
|
|
*/
|
|
lock->write_wait.last=data->prev; /* Put it on wait queue */
|
|
}
|
|
else
|
|
lock->write.last=data->prev;
|
|
if (lock_type >= TL_WRITE_CONCURRENT_INSERT && lock->update_status)
|
|
(*lock->update_status)(data->status_param);
|
|
if (lock_type == TL_READ_NO_INSERT)
|
|
lock->read_no_write_count--;
|
|
data->type=TL_UNLOCK; /* Mark unlocked */
|
|
check_locks(lock,"after releasing lock",1);
|
|
|
|
if (!lock->write.data) /* If no active write locks */
|
|
{
|
|
data=lock->write_wait.data;
|
|
if (!lock->read.data) /* If no more locks in use */
|
|
{
|
|
/* Release write-locks with TL_WRITE or TL_WRITE_ONLY priority first */
|
|
if (data &&
|
|
(data->type != TL_WRITE_LOW_PRIORITY || !lock->read_wait.data ||
|
|
lock->read_wait.data->type < TL_READ_HIGH_PRIORITY))
|
|
{
|
|
if (lock->write_lock_count++ > max_write_lock_count)
|
|
{
|
|
/* Too many write locks in a row; Release all waiting read locks */
|
|
lock->write_lock_count=0;
|
|
if (lock->read_wait.data)
|
|
{
|
|
DBUG_PRINT("info",("Freeing all read_locks because of max_write_lock_count"));
|
|
free_all_read_locks(lock,0);
|
|
goto end;
|
|
}
|
|
}
|
|
for (;;)
|
|
{
|
|
if (((*data->prev)=data->next)) /* remove from wait-list */
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->write_wait.last=data->prev;
|
|
(*lock->write.last)=data; /* Put in execute list */
|
|
data->prev=lock->write.last;
|
|
data->next=0;
|
|
lock->write.last= &data->next;
|
|
if (data->type == TL_WRITE_CONCURRENT_INSERT &&
|
|
(*lock->check_status)(data->status_param))
|
|
data->type=TL_WRITE; /* Upgrade lock */
|
|
DBUG_PRINT("lock",("giving write lock of type %d to thread: %ld",
|
|
data->type, data->owner->info->thread_id));
|
|
{
|
|
pthread_cond_t *cond=data->cond;
|
|
data->cond=0; /* Mark thread free */
|
|
VOID(pthread_cond_signal(cond)); /* Start waiting thread */
|
|
}
|
|
if (data->type != TL_WRITE_ALLOW_WRITE ||
|
|
!lock->write_wait.data ||
|
|
lock->write_wait.data->type != TL_WRITE_ALLOW_WRITE)
|
|
break;
|
|
data=lock->write_wait.data; /* Free this too */
|
|
}
|
|
if (data->type >= TL_WRITE_LOW_PRIORITY)
|
|
{
|
|
check_locks(lock,"giving write lock",0);
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
/* Release possible read locks together with the write lock */
|
|
}
|
|
if (lock->read_wait.data)
|
|
free_all_read_locks(lock,
|
|
data &&
|
|
(data->type == TL_WRITE_CONCURRENT_INSERT ||
|
|
data->type == TL_WRITE_ALLOW_WRITE));
|
|
else
|
|
{
|
|
DBUG_PRINT("lock",("No waiting read locks to free"));
|
|
}
|
|
}
|
|
else if (data &&
|
|
(lock_type=data->type) <= TL_WRITE_DELAYED &&
|
|
((lock_type != TL_WRITE_CONCURRENT_INSERT &&
|
|
lock_type != TL_WRITE_ALLOW_WRITE) ||
|
|
!lock->read_no_write_count))
|
|
{
|
|
/*
|
|
For DELAYED, ALLOW_READ, WRITE_ALLOW_WRITE or CONCURRENT_INSERT locks
|
|
start WRITE locks together with the READ locks
|
|
*/
|
|
if (lock_type == TL_WRITE_CONCURRENT_INSERT &&
|
|
(*lock->check_status)(data->status_param))
|
|
{
|
|
data->type=TL_WRITE; /* Upgrade lock */
|
|
if (lock->read_wait.data)
|
|
free_all_read_locks(lock,0);
|
|
goto end;
|
|
}
|
|
do {
|
|
pthread_cond_t *cond=data->cond;
|
|
if (((*data->prev)=data->next)) /* remove from wait-list */
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->write_wait.last=data->prev;
|
|
(*lock->write.last)=data; /* Put in execute list */
|
|
data->prev=lock->write.last;
|
|
lock->write.last= &data->next;
|
|
data->next=0; /* Only one write lock */
|
|
data->cond=0; /* Mark thread free */
|
|
VOID(pthread_cond_signal(cond)); /* Start waiting thread */
|
|
} while (lock_type == TL_WRITE_ALLOW_WRITE &&
|
|
(data=lock->write_wait.data) &&
|
|
data->type == TL_WRITE_ALLOW_WRITE);
|
|
if (lock->read_wait.data)
|
|
free_all_read_locks(lock,
|
|
(lock_type == TL_WRITE_CONCURRENT_INSERT ||
|
|
lock_type == TL_WRITE_ALLOW_WRITE));
|
|
}
|
|
else if (!data && lock->read_wait.data)
|
|
free_all_read_locks(lock,0);
|
|
}
|
|
end:
|
|
check_locks(lock,"thr_unlock",0);
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
|
|
/*
|
|
** Get all locks in a specific order to avoid dead-locks
|
|
** Sort acording to lock position and put write_locks before read_locks if
|
|
** lock on same lock.
|
|
*/
|
|
|
|
|
|
#define LOCK_CMP(A,B) ((byte*) (A->lock) - (uint) ((A)->type) < (byte*) (B->lock)- (uint) ((B)->type))
|
|
|
|
static void sort_locks(THR_LOCK_DATA **data,uint count)
|
|
{
|
|
THR_LOCK_DATA **pos,**end,**prev,*tmp;
|
|
|
|
/* Sort locks with insertion sort (fast because almost always few locks) */
|
|
|
|
for (pos=data+1,end=data+count; pos < end ; pos++)
|
|
{
|
|
tmp= *pos;
|
|
if (LOCK_CMP(tmp,pos[-1]))
|
|
{
|
|
prev=pos;
|
|
do {
|
|
prev[0]=prev[-1];
|
|
} while (--prev != data && LOCK_CMP(tmp,prev[-1]));
|
|
prev[0]=tmp;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
enum enum_thr_lock_result
|
|
thr_multi_lock(THR_LOCK_DATA **data, uint count, THR_LOCK_OWNER *owner)
|
|
{
|
|
THR_LOCK_DATA **pos,**end;
|
|
DBUG_ENTER("thr_multi_lock");
|
|
DBUG_PRINT("lock",("data: 0x%lx count: %d",data,count));
|
|
if (count > 1)
|
|
sort_locks(data,count);
|
|
/* lock everything */
|
|
for (pos=data,end=data+count; pos < end ; pos++)
|
|
{
|
|
enum enum_thr_lock_result result= thr_lock(*pos, owner, (*pos)->type);
|
|
if (result != THR_LOCK_SUCCESS)
|
|
{ /* Aborted */
|
|
thr_multi_unlock(data,(uint) (pos-data));
|
|
DBUG_RETURN(result);
|
|
}
|
|
#ifdef MAIN
|
|
printf("Thread: %s Got lock: 0x%lx type: %d\n",my_thread_name(),
|
|
(long) pos[0]->lock, pos[0]->type); fflush(stdout);
|
|
#endif
|
|
}
|
|
/*
|
|
Ensure that all get_locks() have the same status
|
|
If we lock the same table multiple times, we must use the same
|
|
status_param!
|
|
*/
|
|
#if !defined(DONT_USE_RW_LOCKS)
|
|
if (count > 1)
|
|
{
|
|
THR_LOCK_DATA *last_lock= end[-1];
|
|
pos=end-1;
|
|
do
|
|
{
|
|
pos--;
|
|
if (last_lock->lock == (*pos)->lock &&
|
|
last_lock->lock->copy_status)
|
|
{
|
|
if (last_lock->type <= TL_READ_NO_INSERT)
|
|
{
|
|
THR_LOCK_DATA **read_lock;
|
|
/*
|
|
If we are locking the same table with read locks we must ensure
|
|
that all tables share the status of the last write lock or
|
|
the same read lock.
|
|
*/
|
|
for (;
|
|
(*pos)->type <= TL_READ_NO_INSERT &&
|
|
pos != data &&
|
|
pos[-1]->lock == (*pos)->lock ;
|
|
pos--) ;
|
|
|
|
read_lock = pos+1;
|
|
do
|
|
{
|
|
(last_lock->lock->copy_status)((*read_lock)->status_param,
|
|
(*pos)->status_param);
|
|
} while (*(read_lock++) != last_lock);
|
|
last_lock= (*pos); /* Point at last write lock */
|
|
}
|
|
else
|
|
(*last_lock->lock->copy_status)((*pos)->status_param,
|
|
last_lock->status_param);
|
|
}
|
|
else
|
|
last_lock=(*pos);
|
|
} while (pos != data);
|
|
}
|
|
#endif
|
|
DBUG_RETURN(THR_LOCK_SUCCESS);
|
|
}
|
|
|
|
/* free all locks */
|
|
|
|
void thr_multi_unlock(THR_LOCK_DATA **data,uint count)
|
|
{
|
|
THR_LOCK_DATA **pos,**end;
|
|
DBUG_ENTER("thr_multi_unlock");
|
|
DBUG_PRINT("lock",("data: 0x%lx count: %d",data,count));
|
|
|
|
for (pos=data,end=data+count; pos < end ; pos++)
|
|
{
|
|
#ifdef MAIN
|
|
printf("Thread: %s Rel lock: 0x%lx type: %d\n",
|
|
my_thread_name(), (long) pos[0]->lock, pos[0]->type);
|
|
fflush(stdout);
|
|
#endif
|
|
if ((*pos)->type != TL_UNLOCK)
|
|
thr_unlock(*pos);
|
|
else
|
|
{
|
|
DBUG_PRINT("lock",("Free lock: data: 0x%lx thread: %ld lock: 0x%lx",
|
|
*pos, (*pos)->owner->info->thread_id, (*pos)->lock));
|
|
}
|
|
}
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
/*
|
|
Abort all threads waiting for a lock. The lock will be upgraded to
|
|
TL_WRITE_ONLY to abort any new accesses to the lock
|
|
*/
|
|
|
|
void thr_abort_locks(THR_LOCK *lock)
|
|
{
|
|
THR_LOCK_DATA *data;
|
|
DBUG_ENTER("thr_abort_locks");
|
|
pthread_mutex_lock(&lock->mutex);
|
|
|
|
for (data=lock->read_wait.data; data ; data=data->next)
|
|
{
|
|
data->type=TL_UNLOCK; /* Mark killed */
|
|
/* It's safe to signal the cond first: we're still holding the mutex. */
|
|
pthread_cond_signal(data->cond);
|
|
data->cond=0; /* Removed from list */
|
|
}
|
|
for (data=lock->write_wait.data; data ; data=data->next)
|
|
{
|
|
data->type=TL_UNLOCK;
|
|
pthread_cond_signal(data->cond);
|
|
data->cond=0;
|
|
}
|
|
lock->read_wait.last= &lock->read_wait.data;
|
|
lock->write_wait.last= &lock->write_wait.data;
|
|
lock->read_wait.data=lock->write_wait.data=0;
|
|
if (lock->write.data)
|
|
lock->write.data->type=TL_WRITE_ONLY;
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_VOID_RETURN;
|
|
}
|
|
|
|
|
|
/*
|
|
Abort all locks for specific table/thread combination
|
|
|
|
This is used to abort all locks for a specific thread
|
|
*/
|
|
|
|
my_bool thr_abort_locks_for_thread(THR_LOCK *lock, pthread_t thread)
|
|
{
|
|
THR_LOCK_DATA *data;
|
|
my_bool found= FALSE;
|
|
DBUG_ENTER("thr_abort_locks_for_thread");
|
|
|
|
pthread_mutex_lock(&lock->mutex);
|
|
for (data= lock->read_wait.data; data ; data= data->next)
|
|
{
|
|
if (pthread_equal(thread, data->owner->info->thread))
|
|
{
|
|
DBUG_PRINT("info",("Aborting read-wait lock"));
|
|
data->type= TL_UNLOCK; /* Mark killed */
|
|
/* It's safe to signal the cond first: we're still holding the mutex. */
|
|
found= TRUE;
|
|
pthread_cond_signal(data->cond);
|
|
data->cond= 0; /* Removed from list */
|
|
|
|
if (((*data->prev)= data->next))
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->read_wait.last= data->prev;
|
|
}
|
|
}
|
|
for (data= lock->write_wait.data; data ; data= data->next)
|
|
{
|
|
if (pthread_equal(thread, data->owner->info->thread))
|
|
{
|
|
DBUG_PRINT("info",("Aborting write-wait lock"));
|
|
data->type= TL_UNLOCK;
|
|
found= TRUE;
|
|
pthread_cond_signal(data->cond);
|
|
data->cond= 0;
|
|
|
|
if (((*data->prev)= data->next))
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->write_wait.last= data->prev;
|
|
}
|
|
}
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(found);
|
|
}
|
|
|
|
|
|
|
|
/* Upgrade a WRITE_DELAY lock to a WRITE_LOCK */
|
|
|
|
my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data)
|
|
{
|
|
THR_LOCK *lock=data->lock;
|
|
DBUG_ENTER("thr_upgrade_write_delay_lock");
|
|
|
|
pthread_mutex_lock(&lock->mutex);
|
|
if (data->type == TL_UNLOCK || data->type >= TL_WRITE_LOW_PRIORITY)
|
|
{
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(data->type == TL_UNLOCK); /* Test if Aborted */
|
|
}
|
|
check_locks(lock,"before upgrading lock",0);
|
|
/* TODO: Upgrade to TL_WRITE_CONCURRENT_INSERT in some cases */
|
|
data->type=TL_WRITE; /* Upgrade lock */
|
|
|
|
/* Check if someone has given us the lock */
|
|
if (!data->cond)
|
|
{
|
|
if (!lock->read.data) /* No read locks */
|
|
{ /* We have the lock */
|
|
if (data->lock->get_status)
|
|
(*data->lock->get_status)(data->status_param, 0);
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(0);
|
|
}
|
|
|
|
if (((*data->prev)=data->next)) /* remove from lock-list */
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->write.last=data->prev;
|
|
|
|
if ((data->next=lock->write_wait.data)) /* Put first in lock_list */
|
|
data->next->prev= &data->next;
|
|
else
|
|
lock->write_wait.last= &data->next;
|
|
data->prev= &lock->write_wait.data;
|
|
lock->write_wait.data=data;
|
|
check_locks(lock,"upgrading lock",0);
|
|
}
|
|
else
|
|
{
|
|
check_locks(lock,"waiting for lock",0);
|
|
}
|
|
DBUG_RETURN(wait_for_lock(&lock->write_wait,data,1));
|
|
}
|
|
|
|
|
|
/* downgrade a WRITE lock to a WRITE_DELAY lock if there is pending locks */
|
|
|
|
my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data)
|
|
{
|
|
THR_LOCK *lock=data->lock;
|
|
DBUG_ENTER("thr_reschedule_write_lock");
|
|
|
|
pthread_mutex_lock(&lock->mutex);
|
|
if (!lock->read_wait.data) /* No waiting read locks */
|
|
{
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(0);
|
|
}
|
|
|
|
data->type=TL_WRITE_DELAYED;
|
|
if (lock->update_status)
|
|
(*lock->update_status)(data->status_param);
|
|
if (((*data->prev)=data->next)) /* remove from lock-list */
|
|
data->next->prev= data->prev;
|
|
else
|
|
lock->write.last=data->prev;
|
|
|
|
if ((data->next=lock->write_wait.data)) /* Put first in lock_list */
|
|
data->next->prev= &data->next;
|
|
else
|
|
lock->write_wait.last= &data->next;
|
|
data->prev= &lock->write_wait.data;
|
|
data->cond=get_cond(); /* This was zero */
|
|
lock->write_wait.data=data;
|
|
free_all_read_locks(lock,0);
|
|
|
|
pthread_mutex_unlock(&lock->mutex);
|
|
DBUG_RETURN(thr_upgrade_write_delay_lock(data));
|
|
}
|
|
|
|
|
|
#include <my_sys.h>
|
|
|
|
static void thr_print_lock(const char* name,struct st_lock_list *list)
|
|
{
|
|
THR_LOCK_DATA *data,**prev;
|
|
uint count=0;
|
|
|
|
if (list->data)
|
|
{
|
|
printf("%-10s: ",name);
|
|
prev= &list->data;
|
|
for (data=list->data; data && count++ < MAX_LOCKS ; data=data->next)
|
|
{
|
|
printf("0x%lx (%lu:%d); ", (ulong) data, data->owner->info->thread_id,
|
|
(int) data->type);
|
|
if (data->prev != prev)
|
|
printf("\nWarning: prev didn't point at previous lock\n");
|
|
prev= &data->next;
|
|
}
|
|
puts("");
|
|
if (prev != list->last)
|
|
printf("Warning: last didn't point at last lock\n");
|
|
}
|
|
}
|
|
|
|
void thr_print_locks(void)
|
|
{
|
|
LIST *list;
|
|
uint count=0;
|
|
|
|
pthread_mutex_lock(&THR_LOCK_lock);
|
|
puts("Current locks:");
|
|
for (list= thr_lock_thread_list; list && count++ < MAX_THREADS;
|
|
list= list_rest(list))
|
|
{
|
|
THR_LOCK *lock=(THR_LOCK*) list->data;
|
|
VOID(pthread_mutex_lock(&lock->mutex));
|
|
printf("lock: 0x%lx:",(ulong) lock);
|
|
if ((lock->write_wait.data || lock->read_wait.data) &&
|
|
(! lock->read.data && ! lock->write.data))
|
|
printf(" WARNING: ");
|
|
if (lock->write.data)
|
|
printf(" write");
|
|
if (lock->write_wait.data)
|
|
printf(" write_wait");
|
|
if (lock->read.data)
|
|
printf(" read");
|
|
if (lock->read_wait.data)
|
|
printf(" read_wait");
|
|
puts("");
|
|
thr_print_lock("write",&lock->write);
|
|
thr_print_lock("write_wait",&lock->write_wait);
|
|
thr_print_lock("read",&lock->read);
|
|
thr_print_lock("read_wait",&lock->read_wait);
|
|
VOID(pthread_mutex_unlock(&lock->mutex));
|
|
puts("");
|
|
}
|
|
fflush(stdout);
|
|
pthread_mutex_unlock(&THR_LOCK_lock);
|
|
}
|
|
|
|
#endif /* THREAD */
|
|
|
|
/*****************************************************************************
|
|
** Test of thread locks
|
|
****************************************************************************/
|
|
|
|
#ifdef MAIN
|
|
|
|
#ifdef THREAD
|
|
|
|
struct st_test {
|
|
uint lock_nr;
|
|
enum thr_lock_type lock_type;
|
|
};
|
|
|
|
THR_LOCK locks[5]; /* 4 locks */
|
|
|
|
struct st_test test_0[] = {{0,TL_READ}}; /* One lock */
|
|
struct st_test test_1[] = {{0,TL_READ},{0,TL_WRITE}}; /* Read and write lock of lock 0 */
|
|
struct st_test test_2[] = {{1,TL_WRITE},{0,TL_READ},{2,TL_READ}};
|
|
struct st_test test_3[] = {{2,TL_WRITE},{1,TL_READ},{0,TL_READ}}; /* Deadlock with test_2 ? */
|
|
struct st_test test_4[] = {{0,TL_WRITE},{0,TL_READ},{0,TL_WRITE},{0,TL_READ}};
|
|
struct st_test test_5[] = {{0,TL_READ},{1,TL_READ},{2,TL_READ},{3,TL_READ}}; /* Many reads */
|
|
struct st_test test_6[] = {{0,TL_WRITE},{1,TL_WRITE},{2,TL_WRITE},{3,TL_WRITE}}; /* Many writes */
|
|
struct st_test test_7[] = {{3,TL_READ}};
|
|
struct st_test test_8[] = {{1,TL_READ_NO_INSERT},{2,TL_READ_NO_INSERT},{3,TL_READ_NO_INSERT}}; /* Should be quick */
|
|
struct st_test test_9[] = {{4,TL_READ_HIGH_PRIORITY}};
|
|
struct st_test test_10[] ={{4,TL_WRITE}};
|
|
struct st_test test_11[] = {{0,TL_WRITE_LOW_PRIORITY},{1,TL_WRITE_LOW_PRIORITY},{2,TL_WRITE_LOW_PRIORITY},{3,TL_WRITE_LOW_PRIORITY}}; /* Many writes */
|
|
struct st_test test_12[] = {{0,TL_WRITE_ALLOW_READ},{1,TL_WRITE_ALLOW_READ},{2,TL_WRITE_ALLOW_READ},{3,TL_WRITE_ALLOW_READ}}; /* Many writes */
|
|
struct st_test test_13[] = {{0,TL_WRITE_CONCURRENT_INSERT},{1,TL_WRITE_CONCURRENT_INSERT},{2,TL_WRITE_CONCURRENT_INSERT},{3,TL_WRITE_CONCURRENT_INSERT}};
|
|
struct st_test test_14[] = {{0,TL_WRITE_CONCURRENT_INSERT},{1,TL_READ}};
|
|
struct st_test test_15[] = {{0,TL_WRITE_ALLOW_WRITE},{1,TL_READ}};
|
|
struct st_test test_16[] = {{0,TL_WRITE_ALLOW_WRITE},{1,TL_WRITE_ALLOW_WRITE}};
|
|
|
|
struct st_test *tests[] = {test_0,test_1,test_2,test_3,test_4,test_5,test_6,
|
|
test_7,test_8,test_9,test_10,test_11,test_12,
|
|
test_13,test_14,test_15,test_16};
|
|
int lock_counts[]= {sizeof(test_0)/sizeof(struct st_test),
|
|
sizeof(test_1)/sizeof(struct st_test),
|
|
sizeof(test_2)/sizeof(struct st_test),
|
|
sizeof(test_3)/sizeof(struct st_test),
|
|
sizeof(test_4)/sizeof(struct st_test),
|
|
sizeof(test_5)/sizeof(struct st_test),
|
|
sizeof(test_6)/sizeof(struct st_test),
|
|
sizeof(test_7)/sizeof(struct st_test),
|
|
sizeof(test_8)/sizeof(struct st_test),
|
|
sizeof(test_9)/sizeof(struct st_test),
|
|
sizeof(test_10)/sizeof(struct st_test),
|
|
sizeof(test_11)/sizeof(struct st_test),
|
|
sizeof(test_12)/sizeof(struct st_test),
|
|
sizeof(test_13)/sizeof(struct st_test),
|
|
sizeof(test_14)/sizeof(struct st_test),
|
|
sizeof(test_15)/sizeof(struct st_test),
|
|
sizeof(test_16)/sizeof(struct st_test)
|
|
};
|
|
|
|
|
|
static pthread_cond_t COND_thread_count;
|
|
static pthread_mutex_t LOCK_thread_count;
|
|
static uint thread_count;
|
|
static ulong sum=0;
|
|
|
|
#define MAX_LOCK_COUNT 8
|
|
|
|
/* The following functions is for WRITE_CONCURRENT_INSERT */
|
|
|
|
static void test_get_status(void* param __attribute__((unused)),
|
|
int concurrent_insert __attribute__((unused)))
|
|
{
|
|
}
|
|
|
|
static void test_copy_status(void* to __attribute__((unused)) ,
|
|
void *from __attribute__((unused)))
|
|
{
|
|
}
|
|
|
|
static my_bool test_check_status(void* param __attribute__((unused)))
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void *test_thread(void *arg)
|
|
{
|
|
int i,j,param=*((int*) arg);
|
|
THR_LOCK_DATA data[MAX_LOCK_COUNT];
|
|
THR_LOCK_OWNER owner;
|
|
THR_LOCK_INFO lock_info;
|
|
THR_LOCK_DATA *multi_locks[MAX_LOCK_COUNT];
|
|
my_thread_init();
|
|
|
|
printf("Thread %s (%d) started\n",my_thread_name(),param); fflush(stdout);
|
|
|
|
|
|
thr_lock_info_init(&lock_info);
|
|
thr_lock_owner_init(&owner, &lock_info);
|
|
for (i=0; i < lock_counts[param] ; i++)
|
|
thr_lock_data_init(locks+tests[param][i].lock_nr,data+i,NULL);
|
|
for (j=1 ; j < 10 ; j++) /* try locking 10 times */
|
|
{
|
|
for (i=0; i < lock_counts[param] ; i++)
|
|
{ /* Init multi locks */
|
|
multi_locks[i]= &data[i];
|
|
data[i].type= tests[param][i].lock_type;
|
|
}
|
|
thr_multi_lock(multi_locks, lock_counts[param], &owner);
|
|
pthread_mutex_lock(&LOCK_thread_count);
|
|
{
|
|
int tmp=rand() & 7; /* Do something from 0-2 sec */
|
|
if (tmp == 0)
|
|
sleep(1);
|
|
else if (tmp == 1)
|
|
sleep(2);
|
|
else
|
|
{
|
|
ulong k;
|
|
for (k=0 ; k < (ulong) (tmp-2)*100000L ; k++)
|
|
sum+=k;
|
|
}
|
|
}
|
|
pthread_mutex_unlock(&LOCK_thread_count);
|
|
thr_multi_unlock(multi_locks,lock_counts[param]);
|
|
}
|
|
|
|
printf("Thread %s (%d) ended\n",my_thread_name(),param); fflush(stdout);
|
|
thr_print_locks();
|
|
pthread_mutex_lock(&LOCK_thread_count);
|
|
thread_count--;
|
|
VOID(pthread_cond_signal(&COND_thread_count)); /* Tell main we are ready */
|
|
pthread_mutex_unlock(&LOCK_thread_count);
|
|
free((gptr) arg);
|
|
return 0;
|
|
}
|
|
|
|
|
|
int main(int argc __attribute__((unused)),char **argv __attribute__((unused)))
|
|
{
|
|
pthread_t tid;
|
|
pthread_attr_t thr_attr;
|
|
int i,*param,error;
|
|
MY_INIT(argv[0]);
|
|
if (argc > 1 && argv[1][0] == '-' && argv[1][1] == '#')
|
|
DBUG_PUSH(argv[1]+2);
|
|
|
|
printf("Main thread: %s\n",my_thread_name());
|
|
|
|
if ((error=pthread_cond_init(&COND_thread_count,NULL)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_cond_init (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
if ((error=pthread_mutex_init(&LOCK_thread_count,MY_MUTEX_INIT_FAST)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_cond_init (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
|
|
for (i=0 ; i < (int) array_elements(locks) ; i++)
|
|
{
|
|
thr_lock_init(locks+i);
|
|
locks[i].check_status= test_check_status;
|
|
locks[i].update_status=test_get_status;
|
|
locks[i].copy_status= test_copy_status;
|
|
locks[i].get_status= test_get_status;
|
|
}
|
|
if ((error=pthread_attr_init(&thr_attr)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_attr_init (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
if ((error=pthread_attr_setdetachstate(&thr_attr,PTHREAD_CREATE_DETACHED)))
|
|
{
|
|
fprintf(stderr,
|
|
"Got error: %d from pthread_attr_setdetachstate (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
#ifndef pthread_attr_setstacksize /* void return value */
|
|
if ((error=pthread_attr_setstacksize(&thr_attr,65536L)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_attr_setstacksize (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
#endif
|
|
#ifdef HAVE_THR_SETCONCURRENCY
|
|
VOID(thr_setconcurrency(2));
|
|
#endif
|
|
for (i=0 ; i < (int) array_elements(lock_counts) ; i++)
|
|
{
|
|
param=(int*) malloc(sizeof(int));
|
|
*param=i;
|
|
|
|
if ((error=pthread_mutex_lock(&LOCK_thread_count)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_mutex_lock (errno: %d)",
|
|
error,errno);
|
|
exit(1);
|
|
}
|
|
if ((error=pthread_create(&tid,&thr_attr,test_thread,(void*) param)))
|
|
{
|
|
fprintf(stderr,"Got error: %d from pthread_create (errno: %d)\n",
|
|
error,errno);
|
|
pthread_mutex_unlock(&LOCK_thread_count);
|
|
exit(1);
|
|
}
|
|
thread_count++;
|
|
pthread_mutex_unlock(&LOCK_thread_count);
|
|
}
|
|
|
|
pthread_attr_destroy(&thr_attr);
|
|
if ((error=pthread_mutex_lock(&LOCK_thread_count)))
|
|
fprintf(stderr,"Got error: %d from pthread_mutex_lock\n",error);
|
|
while (thread_count)
|
|
{
|
|
if ((error=pthread_cond_wait(&COND_thread_count,&LOCK_thread_count)))
|
|
fprintf(stderr,"Got error: %d from pthread_cond_wait\n",error);
|
|
}
|
|
if ((error=pthread_mutex_unlock(&LOCK_thread_count)))
|
|
fprintf(stderr,"Got error: %d from pthread_mutex_unlock\n",error);
|
|
for (i=0 ; i < (int) array_elements(locks) ; i++)
|
|
thr_lock_delete(locks+i);
|
|
#ifdef EXTRA_DEBUG
|
|
if (found_errors)
|
|
printf("Got %d warnings\n",found_errors);
|
|
else
|
|
#endif
|
|
printf("Test succeeded\n");
|
|
return 0;
|
|
}
|
|
|
|
#else /* THREAD */
|
|
|
|
int main(int argc __attribute__((unused)),char **argv __attribute__((unused)))
|
|
{
|
|
printf("thr_lock disabled because we are not using threads\n");
|
|
exit(1);
|
|
}
|
|
|
|
#endif /* THREAD */
|
|
#endif /* MAIN */
|