database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-11-03 14:33:32 +03:00
Code Activity
Files
f285b4fcee16da820bd0a1b6411f66b85bcd0806
mariadb/mysys/thr_lock.c

1396 lines
40 KiB
C
Raw Blame History

/* 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;
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;
}
#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_thread, bool no_cond)
{
THR_LOCK_DATA *data,**prev;
uint count=0;
pthread_t first_thread;
LINT_INIT(first_thread);
prev= &list->data;
if (list->data)
{
enum thr_lock_type last_lock_type=list->data->type;
if (same_thread && list->data)
first_thread=list->data->thread;
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_thread && ! pthread_equal(data->thread,first_thread) &&
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++;
}
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 (!pthread_equal(lock->write.data->thread,
lock->read.data->thread) &&
((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;
}
/* 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->thread=pthread_self();
data->thread_id=my_thread_id(); /* for debugging */
data->status_param=param;
data->cond=0;
}
static inline my_bool have_old_read_lock(THR_LOCK_DATA *data,pthread_t thread)
{
for ( ; data ; data=data->next)
{
if ((pthread_equal(data->thread,thread)))
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 my_bool wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
my_bool in_wait_list)
{
pthread_cond_t *cond=get_cond();
struct st_my_thread_var *thread_var=my_thread_var;
int result;
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;
while (!thread_var->abort || in_wait_list)
{
pthread_cond_wait(cond,&data->lock->mutex);
if (data->cond != cond)
break;
}
if (data->cond || data->type == TL_UNLOCK)
{
if (data->cond) /* aborted */
{
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 */
result=1; /* Didn't get lock */
check_locks(data->lock,"failed wait_for_lock",0);
}
else
{
result=0;
statistic_increment(locks_waited, &THR_LOCK_lock);
if (data->lock->get_status)
(*data->lock->get_status)(data->status_param);
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;
}
int thr_lock(THR_LOCK_DATA *data,enum thr_lock_type lock_type)
{
THR_LOCK *lock=data->lock;
int result=0;
DBUG_ENTER("thr_lock");
data->next=0;
data->cond=0; /* safety */
data->type=lock_type;
data->thread=pthread_self(); /* Must be reset ! */
data->thread_id=my_thread_id(); /* Must be reset ! */
VOID(pthread_mutex_lock(&lock->mutex));
DBUG_PRINT("lock",("data: 0x%lx thread: %ld lock: 0x%lx type: %d",
data,data->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->thread_id));
if (pthread_equal(data->thread,lock->write.data->thread) ||
(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 ((int) lock_type == (int) 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);
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=1; /* 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->thread))
{ /* 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);
if ((int) lock_type == (int) 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;
}
/* Can't get lock yet; Wait for it */
DBUG_RETURN(wait_for_lock(&lock->read_wait,data,0));
}
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=1; /* 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=1; /* 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 (pthread_equal(data->thread,lock->write.data->thread) ||
(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);
statistic_increment(locks_immediate,&THR_LOCK_lock);
goto end;
}
DBUG_PRINT("lock",("write locked by thread: %ld",
lock->write.data->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 */
if (lock_type == TL_WRITE_CONCURRENT_INSERT &&
(*lock->check_status)(data->status_param))
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);
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->thread_id,data->type));
}
DBUG_RETURN(wait_for_lock(&lock->write_wait,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->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->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->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;
}
}
}
int thr_multi_lock(THR_LOCK_DATA **data,uint count)
{
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++)
{
if (thr_lock(*pos,(*pos)->type))
{ /* Aborted */
thr_multi_unlock(data,(uint) (pos-data));
DBUG_RETURN(1);
}
#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(0);
}
/* 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)->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 */
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
*/
void thr_abort_locks_for_thread(THR_LOCK *lock, pthread_t thread)
{
THR_LOCK_DATA *data;
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->thread))
{
DBUG_PRINT("info",("Aborting read-wait lock"));
data->type= TL_UNLOCK; /* Mark killed */
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->thread))
{
DBUG_PRINT("info",("Aborting write-wait lock"));
data->type= TL_UNLOCK;
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_VOID_RETURN;
}
/* 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);
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->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=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)))
{
}
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_DATA *multi_locks[MAX_LOCK_COUNT];
my_thread_init();
printf("Thread %s (%d) started\n",my_thread_name(),param); fflush(stdout);
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]);
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 */
View Git Blame Copy Permalink