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801deedcf2
When compressed myisam files are opened, they are always memory mapped sometimes causing memory swapping problems. When we mmap the myisam compressed tables of size greater than the memory available, the kswapd0 process utilization is very high consuming 30-40% of the cpu. This happens only with linux kernels older than 2.6.9 With newer linux kernels, we don't have this problem of high cpu consumption and this option may not be required. The option 'myisam_mmap_size' is added to limit the amount of memory used for memory mapping of myisam files. This option is not dynamic. The default value on 32 bit system is 4294967295 bytes and on 64 bit system it is 18446744073709547520 bytes. Note: Testcase only tests the option variable. The actual bug has be to tested manually.
433 lines
12 KiB
C
433 lines
12 KiB
C
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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Functions to handle initializating and allocationg of all mysys & debug
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thread variables.
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*/
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#include "mysys_priv.h"
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#include <m_string.h>
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#include <signal.h>
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#ifdef THREAD
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#ifdef USE_TLS
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pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
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#else
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pthread_key(struct st_my_thread_var, THR_KEY_mysys);
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#endif /* USE_TLS */
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pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open,
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THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap,
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THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads,
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THR_LOCK_myisam_mmap;
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pthread_cond_t THR_COND_threads;
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uint THR_thread_count= 0;
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uint my_thread_end_wait_time= 5;
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_t LOCK_localtime_r;
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_t LOCK_gethostbyname_r;
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#endif
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#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
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pthread_mutexattr_t my_fast_mutexattr;
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#endif
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#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
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pthread_mutexattr_t my_errorcheck_mutexattr;
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#endif
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#ifdef TARGET_OS_LINUX
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/*
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Dummy thread spawned in my_thread_global_init() below to avoid
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race conditions in NPTL pthread_exit code.
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*/
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static pthread_handler_t
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nptl_pthread_exit_hack_handler(void *arg __attribute__((unused)))
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{
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/* Do nothing! */
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pthread_exit(0);
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return 0;
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}
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#endif /* TARGET_OS_LINUX */
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static uint get_thread_lib(void);
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/*
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initialize thread environment
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SYNOPSIS
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my_thread_global_init()
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RETURN
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0 ok
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1 error (Couldn't create THR_KEY_mysys)
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*/
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my_bool my_thread_global_init(void)
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{
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int pth_ret;
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thd_lib_detected= get_thread_lib();
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if ((pth_ret= pthread_key_create(&THR_KEY_mysys, NULL)) != 0)
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{
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fprintf(stderr,"Can't initialize threads: error %d\n", pth_ret);
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return 1;
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}
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#ifdef TARGET_OS_LINUX
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/*
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BUG#24507: Race conditions inside current NPTL pthread_exit()
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implementation.
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To avoid a possible segmentation fault during concurrent
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executions of pthread_exit(), a dummy thread is spawned which
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initializes internal variables of pthread lib. See bug description
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for a full explanation.
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TODO: Remove this code when fixed versions of glibc6 are in common
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use.
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*/
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if (thd_lib_detected == THD_LIB_NPTL)
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{
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pthread_t dummy_thread;
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pthread_attr_t dummy_thread_attr;
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pthread_attr_init(&dummy_thread_attr);
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pthread_attr_setdetachstate(&dummy_thread_attr, PTHREAD_CREATE_JOINABLE);
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if (pthread_create(&dummy_thread,&dummy_thread_attr,
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nptl_pthread_exit_hack_handler, NULL) == 0)
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(void)pthread_join(dummy_thread, NULL);
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}
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#endif /* TARGET_OS_LINUX */
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#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
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/*
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Set mutex type to "fast" a.k.a "adaptive"
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In this case the thread may steal the mutex from some other thread
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that is waiting for the same mutex. This will save us some
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context switches but may cause a thread to 'starve forever' while
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waiting for the mutex (not likely if the code within the mutex is
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short).
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*/
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pthread_mutexattr_init(&my_fast_mutexattr);
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pthread_mutexattr_settype(&my_fast_mutexattr,
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PTHREAD_MUTEX_ADAPTIVE_NP);
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#endif
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#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
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/*
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Set mutex type to "errorcheck"
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*/
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pthread_mutexattr_init(&my_errorcheck_mutexattr);
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pthread_mutexattr_settype(&my_errorcheck_mutexattr,
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PTHREAD_MUTEX_ERRORCHECK);
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#endif
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pthread_mutex_init(&THR_LOCK_malloc,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_open,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_lock,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_isam,MY_MUTEX_INIT_SLOW);
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pthread_mutex_init(&THR_LOCK_myisam,MY_MUTEX_INIT_SLOW);
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pthread_mutex_init(&THR_LOCK_myisam_mmap,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_heap,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_net,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_charset,MY_MUTEX_INIT_FAST);
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pthread_mutex_init(&THR_LOCK_threads,MY_MUTEX_INIT_FAST);
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pthread_cond_init(&THR_COND_threads, NULL);
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#if defined( __WIN__) || defined(OS2)
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win_pthread_init();
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#endif
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_init(&LOCK_localtime_r,MY_MUTEX_INIT_SLOW);
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_init(&LOCK_gethostbyname_r,MY_MUTEX_INIT_SLOW);
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#endif
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if (my_thread_init())
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{
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my_thread_global_end(); /* Clean up */
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return 1;
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}
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return 0;
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}
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void my_thread_global_end(void)
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{
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struct timespec abstime;
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my_bool all_threads_killed= 1;
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set_timespec(abstime, my_thread_end_wait_time);
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pthread_mutex_lock(&THR_LOCK_threads);
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while (THR_thread_count > 0)
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{
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int error= pthread_cond_timedwait(&THR_COND_threads, &THR_LOCK_threads,
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&abstime);
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if (error == ETIMEDOUT || error == ETIME)
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{
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#ifdef HAVE_PTHREAD_KILL
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/*
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We shouldn't give an error here, because if we don't have
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pthread_kill(), programs like mysqld can't ensure that all threads
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are killed when we enter here.
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*/
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if (THR_thread_count)
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fprintf(stderr,
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"Error in my_thread_global_end(): %d threads didn't exit\n",
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THR_thread_count);
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#endif
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all_threads_killed= 0;
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break;
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}
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}
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pthread_mutex_unlock(&THR_LOCK_threads);
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pthread_key_delete(THR_KEY_mysys);
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#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
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pthread_mutexattr_destroy(&my_fast_mutexattr);
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#endif
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#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
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pthread_mutexattr_destroy(&my_errorcheck_mutexattr);
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#endif
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pthread_mutex_destroy(&THR_LOCK_malloc);
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pthread_mutex_destroy(&THR_LOCK_open);
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pthread_mutex_destroy(&THR_LOCK_lock);
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pthread_mutex_destroy(&THR_LOCK_isam);
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pthread_mutex_destroy(&THR_LOCK_myisam);
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pthread_mutex_destroy(&THR_LOCK_myisam_mmap);
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pthread_mutex_destroy(&THR_LOCK_heap);
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pthread_mutex_destroy(&THR_LOCK_net);
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pthread_mutex_destroy(&THR_LOCK_charset);
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if (all_threads_killed)
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{
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pthread_mutex_destroy(&THR_LOCK_threads);
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pthread_cond_destroy(&THR_COND_threads);
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}
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#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
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pthread_mutex_destroy(&LOCK_localtime_r);
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#endif
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#ifndef HAVE_GETHOSTBYNAME_R
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pthread_mutex_destroy(&LOCK_gethostbyname_r);
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#endif
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}
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static long thread_id=0;
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/*
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Allocate thread specific memory for the thread, used by mysys and dbug
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SYNOPSIS
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my_thread_init()
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NOTES
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We can't use mutex_locks here if we are using windows as
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we may have compiled the program with SAFE_MUTEX, in which
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case the checking of mutex_locks will not work until
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the pthread_self thread specific variable is initialized.
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This function may called multiple times for a thread, for example
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if one uses my_init() followed by mysql_server_init().
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RETURN
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0 ok
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1 Fatal error; mysys/dbug functions can't be used
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*/
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my_bool my_thread_init(void)
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{
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struct st_my_thread_var *tmp;
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my_bool error=0;
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_init(): thread_id=%ld\n",pthread_self());
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#endif
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#if !defined(__WIN__) || defined(USE_TLS)
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if (my_pthread_getspecific(struct st_my_thread_var *,THR_KEY_mysys))
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{
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_init() called more than once in thread %ld\n",
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pthread_self());
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#endif
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goto end;
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}
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if (!(tmp= (struct st_my_thread_var *) calloc(1, sizeof(*tmp))))
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{
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error= 1;
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goto end;
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}
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pthread_setspecific(THR_KEY_mysys,tmp);
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#else /* defined(__WIN__) && !(defined(USE_TLS) */
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/*
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Skip initialization if the thread specific variable is already initialized
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*/
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if (THR_KEY_mysys.id)
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goto end;
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tmp= &THR_KEY_mysys;
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#endif
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#if defined(__WIN__) && defined(EMBEDDED_LIBRARY)
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tmp->thread_self= (pthread_t)getpid();
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#endif
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pthread_mutex_init(&tmp->mutex,MY_MUTEX_INIT_FAST);
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pthread_cond_init(&tmp->suspend, NULL);
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tmp->init= 1;
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pthread_mutex_lock(&THR_LOCK_threads);
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tmp->id= ++thread_id;
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++THR_thread_count;
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pthread_mutex_unlock(&THR_LOCK_threads);
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end:
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return error;
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}
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/*
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Deallocate memory used by the thread for book-keeping
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SYNOPSIS
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my_thread_end()
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NOTE
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This may be called multiple times for a thread.
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This happens for example when one calls 'mysql_server_init()'
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mysql_server_end() and then ends with a mysql_end().
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*/
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void my_thread_end(void)
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{
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struct st_my_thread_var *tmp;
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tmp= my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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#ifdef EXTRA_DEBUG_THREADS
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fprintf(stderr,"my_thread_end(): tmp: 0x%lx thread_id=%ld\n",
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(long) tmp, pthread_self());
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#endif
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if (tmp && tmp->init)
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{
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#if !defined(DBUG_OFF)
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/* tmp->dbug is allocated inside DBUG library */
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if (tmp->dbug)
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{
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free(tmp->dbug);
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tmp->dbug=0;
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}
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#endif
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#if !defined(__bsdi__) && !defined(__OpenBSD__) || defined(HAVE_mit_thread)
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/* bsdi and openbsd 3.5 dumps core here */
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pthread_cond_destroy(&tmp->suspend);
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#endif
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pthread_mutex_destroy(&tmp->mutex);
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#if (!defined(__WIN__) && !defined(OS2)) || defined(USE_TLS)
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free(tmp);
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#else
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tmp->init= 0;
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#endif
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/*
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Decrement counter for number of running threads. We are using this
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in my_thread_global_end() to wait until all threads have called
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my_thread_end and thus freed all memory they have allocated in
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my_thread_init() and DBUG_xxxx
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*/
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pthread_mutex_lock(&THR_LOCK_threads);
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DBUG_ASSERT(THR_thread_count != 0);
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if (--THR_thread_count == 0)
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pthread_cond_signal(&THR_COND_threads);
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pthread_mutex_unlock(&THR_LOCK_threads);
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}
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/* The following free has to be done, even if my_thread_var() is 0 */
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#if (!defined(__WIN__) && !defined(OS2)) || defined(USE_TLS)
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pthread_setspecific(THR_KEY_mysys,0);
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#endif
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}
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struct st_my_thread_var *_my_thread_var(void)
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{
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struct st_my_thread_var *tmp=
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my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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#if defined(USE_TLS)
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/* This can only happen in a .DLL */
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if (!tmp)
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{
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my_thread_init();
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tmp=my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
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}
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#endif
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return tmp;
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}
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/****************************************************************************
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Get name of current thread.
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****************************************************************************/
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#define UNKNOWN_THREAD -1
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long my_thread_id()
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{
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#if defined(HAVE_PTHREAD_GETSEQUENCE_NP)
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return pthread_getsequence_np(pthread_self());
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#elif (defined(__sun) || defined(__sgi) || defined(__linux__)) && !defined(HAVE_mit_thread)
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return pthread_self();
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#else
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return my_thread_var->id;
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#endif
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}
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#ifdef DBUG_OFF
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const char *my_thread_name(void)
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{
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return "no_name";
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}
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#else
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const char *my_thread_name(void)
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{
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char name_buff[100];
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struct st_my_thread_var *tmp=my_thread_var;
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if (!tmp->name[0])
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{
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long id=my_thread_id();
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sprintf(name_buff,"T@%ld", id);
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strmake(tmp->name,name_buff,THREAD_NAME_SIZE);
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}
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return tmp->name;
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}
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#endif /* DBUG_OFF */
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static uint get_thread_lib(void)
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{
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#ifdef _CS_GNU_LIBPTHREAD_VERSION
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char buff[64];
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confstr(_CS_GNU_LIBPTHREAD_VERSION, buff, sizeof(buff));
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if (!strncasecmp(buff, "NPTL", 4))
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return THD_LIB_NPTL;
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if (!strncasecmp(buff, "linuxthreads", 12))
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return THD_LIB_LT;
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#endif
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return THD_LIB_OTHER;
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}
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#endif /* THREAD */
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