openldap/libraries/libldap_r/tpool.c
Howard Chu 13c39b98b5 Fixup handle_pause()
Return -1 if running on the main thread - which means there
are no worker threads to pause.
2017-04-09 15:39:44 +01:00

1357 lines
34 KiB
C

/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 1998-2017 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
#include "portable.h"
#include <stdio.h>
#include <ac/signal.h>
#include <ac/stdarg.h>
#include <ac/stdlib.h>
#include <ac/string.h>
#include <ac/time.h>
#include <ac/errno.h>
#include "ldap-int.h"
#include "ldap_pvt_thread.h" /* Get the thread interface */
#include "ldap_queue.h"
#define LDAP_THREAD_POOL_IMPLEMENTATION
#include "ldap_thr_debug.h" /* May rename symbols defined below */
#ifndef LDAP_THREAD_HAVE_TPOOL
#ifndef CACHELINE
#define CACHELINE 64
#endif
/* Thread-specific key with data and optional free function */
typedef struct ldap_int_tpool_key_s {
void *ltk_key;
void *ltk_data;
ldap_pvt_thread_pool_keyfree_t *ltk_free;
} ldap_int_tpool_key_t;
/* Max number of thread-specific keys we store per thread.
* We don't expect to use many...
*/
#define MAXKEYS 32
/* Max number of threads */
#define LDAP_MAXTHR 1024 /* must be a power of 2 */
/* (Theoretical) max number of pending requests */
#define MAX_PENDING (INT_MAX/2) /* INT_MAX - (room to avoid overflow) */
/* pool->ltp_pause values */
enum { NOT_PAUSED = 0, WANT_PAUSE = 1, PAUSED = 2 };
/* Context: thread ID and thread-specific key/data pairs */
typedef struct ldap_int_thread_userctx_s {
struct ldap_int_thread_poolq_s *ltu_pq;
ldap_pvt_thread_t ltu_id;
ldap_int_tpool_key_t ltu_key[MAXKEYS];
} ldap_int_thread_userctx_t;
/* Simple {thread ID -> context} hash table; key=ctx->ltu_id.
* Protected by ldap_pvt_thread_pool_mutex.
*/
static struct {
ldap_int_thread_userctx_t *ctx;
/* ctx is valid when not NULL or DELETED_THREAD_CTX */
# define DELETED_THREAD_CTX (&ldap_int_main_thrctx + 1) /* dummy addr */
} thread_keys[LDAP_MAXTHR];
#define TID_HASH(tid, hash) do { \
unsigned const char *ptr_ = (unsigned const char *)&(tid); \
unsigned i_; \
for (i_ = 0, (hash) = ptr_[0]; ++i_ < sizeof(tid);) \
(hash) += ((hash) << 5) ^ ptr_[i_]; \
} while(0)
/* Task for a thread to perform */
typedef struct ldap_int_thread_task_s {
union {
LDAP_STAILQ_ENTRY(ldap_int_thread_task_s) q;
LDAP_SLIST_ENTRY(ldap_int_thread_task_s) l;
} ltt_next;
ldap_pvt_thread_start_t *ltt_start_routine;
void *ltt_arg;
struct ldap_int_thread_poolq_s *ltt_queue;
} ldap_int_thread_task_t;
typedef LDAP_STAILQ_HEAD(tcq, ldap_int_thread_task_s) ldap_int_tpool_plist_t;
struct ldap_int_thread_poolq_s {
void *ltp_free;
struct ldap_int_thread_pool_s *ltp_pool;
/* protect members below */
ldap_pvt_thread_mutex_t ltp_mutex;
/* not paused and something to do for pool_<wrapper/pause/destroy>()
* Used for normal pool operation, to synch between submitter and
* worker threads. Not used for pauses. In normal operation multiple
* queues can rendezvous without acquiring the main pool lock.
*/
ldap_pvt_thread_cond_t ltp_cond;
/* ltp_pause == 0 ? &ltp_pending_list : &empty_pending_list,
* maintaned to reduce work for pool_wrapper()
*/
ldap_int_tpool_plist_t *ltp_work_list;
/* pending tasks, and unused task objects */
ldap_int_tpool_plist_t ltp_pending_list;
LDAP_SLIST_HEAD(tcl, ldap_int_thread_task_s) ltp_free_list;
/* Max number of threads in this queue */
int ltp_max_count;
/* Max pending + paused + idle tasks, negated when ltp_finishing */
int ltp_max_pending;
int ltp_pending_count; /* Pending + paused + idle tasks */
int ltp_active_count; /* Active, not paused/idle tasks */
int ltp_open_count; /* Number of threads */
int ltp_starting; /* Currently starting threads */
};
struct ldap_int_thread_pool_s {
LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
struct ldap_int_thread_poolq_s **ltp_wqs;
/* number of poolqs */
int ltp_numqs;
/* protect members below */
ldap_pvt_thread_mutex_t ltp_mutex;
/* paused and waiting for resume
* When a pause is in effect all workers switch to waiting on
* this cond instead of their per-queue cond.
*/
ldap_pvt_thread_cond_t ltp_cond;
/* ltp_active_queues < 1 && ltp_pause */
ldap_pvt_thread_cond_t ltp_pcond;
/* number of active queues */
int ltp_active_queues;
/* The pool is finishing, waiting for its threads to close.
* They close when ltp_pending_list is done. pool_submit()
* rejects new tasks. ltp_max_pending = -(its old value).
*/
int ltp_finishing;
/* Some active task needs to be the sole active task.
* Atomic variable so ldap_pvt_thread_pool_pausing() can read it.
*/
volatile sig_atomic_t ltp_pause;
/* Max number of threads in pool */
int ltp_max_count;
/* Configured max number of threads in pool, 0 for default (LDAP_MAXTHR) */
int ltp_conf_max_count;
/* Max pending + paused + idle tasks, negated when ltp_finishing */
int ltp_max_pending;
};
static ldap_int_tpool_plist_t empty_pending_list =
LDAP_STAILQ_HEAD_INITIALIZER(empty_pending_list);
static int ldap_int_has_thread_pool = 0;
static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s)
ldap_int_thread_pool_list =
LDAP_STAILQ_HEAD_INITIALIZER(ldap_int_thread_pool_list);
static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex;
static void *ldap_int_thread_pool_wrapper( void *pool );
static ldap_pvt_thread_key_t ldap_tpool_key;
/* Context of the main thread */
static ldap_int_thread_userctx_t ldap_int_main_thrctx;
int
ldap_int_thread_pool_startup ( void )
{
ldap_int_main_thrctx.ltu_id = ldap_pvt_thread_self();
ldap_pvt_thread_key_create( &ldap_tpool_key );
return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex);
}
int
ldap_int_thread_pool_shutdown ( void )
{
struct ldap_int_thread_pool_s *pool;
while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) {
(ldap_pvt_thread_pool_destroy)(&pool, 0); /* ignore thr_debug macro */
}
ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex);
ldap_pvt_thread_key_destroy( ldap_tpool_key );
return(0);
}
/* Create a thread pool */
int
ldap_pvt_thread_pool_init_q (
ldap_pvt_thread_pool_t *tpool,
int max_threads,
int max_pending,
int numqs )
{
ldap_pvt_thread_pool_t pool;
struct ldap_int_thread_poolq_s *pq;
int i, rc, rem_thr, rem_pend;
/* multiple pools are currently not supported (ITS#4943) */
assert(!ldap_int_has_thread_pool);
if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR))
max_threads = 0;
if (! (1 <= max_pending && max_pending <= MAX_PENDING))
max_pending = MAX_PENDING;
*tpool = NULL;
pool = (ldap_pvt_thread_pool_t) LDAP_CALLOC(1,
sizeof(struct ldap_int_thread_pool_s));
if (pool == NULL) return(-1);
pool->ltp_wqs = LDAP_MALLOC(numqs * sizeof(struct ldap_int_thread_poolq_s *));
if (pool->ltp_wqs == NULL) {
LDAP_FREE(pool);
return(-1);
}
for (i=0; i<numqs; i++) {
char *ptr = LDAP_CALLOC(1, sizeof(struct ldap_int_thread_poolq_s) + CACHELINE-1);
if (ptr == NULL) {
for (--i; i>=0; i--)
LDAP_FREE(pool->ltp_wqs[i]->ltp_free);
LDAP_FREE(pool->ltp_wqs);
LDAP_FREE(pool);
return(-1);
}
pool->ltp_wqs[i] = (struct ldap_int_thread_poolq_s *)(((size_t)ptr + CACHELINE-1) & ~(CACHELINE-1));
pool->ltp_wqs[i]->ltp_free = ptr;
}
pool->ltp_numqs = numqs;
pool->ltp_conf_max_count = max_threads;
if ( !max_threads )
max_threads = LDAP_MAXTHR;
rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex);
if (rc != 0) {
fail:
for (i=0; i<numqs; i++)
LDAP_FREE(pool->ltp_wqs[i]->ltp_free);
LDAP_FREE(pool->ltp_wqs);
LDAP_FREE(pool);
return(rc);
}
rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
if (rc != 0)
goto fail;
rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
if (rc != 0)
goto fail;
rem_thr = max_threads % numqs;
rem_pend = max_pending % numqs;
for ( i=0; i<numqs; i++ ) {
pq = pool->ltp_wqs[i];
pq->ltp_pool = pool;
rc = ldap_pvt_thread_mutex_init(&pq->ltp_mutex);
if (rc != 0)
return(rc);
rc = ldap_pvt_thread_cond_init(&pq->ltp_cond);
if (rc != 0)
return(rc);
LDAP_STAILQ_INIT(&pq->ltp_pending_list);
pq->ltp_work_list = &pq->ltp_pending_list;
LDAP_SLIST_INIT(&pq->ltp_free_list);
pq->ltp_max_count = max_threads / numqs;
if ( rem_thr ) {
pq->ltp_max_count++;
rem_thr--;
}
pq->ltp_max_pending = max_pending / numqs;
if ( rem_pend ) {
pq->ltp_max_pending++;
rem_pend--;
}
}
ldap_int_has_thread_pool = 1;
pool->ltp_max_count = max_threads;
pool->ltp_max_pending = max_pending;
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next);
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
/* Start no threads just yet. That can break if the process forks
* later, as slapd does in order to daemonize. On at least POSIX,
* only the forking thread would survive in the child. Yet fork()
* can't unlock/clean up other threads' locks and data structures,
* unless pthread_atfork() handlers have been set up to do so.
*/
*tpool = pool;
return(0);
}
int
ldap_pvt_thread_pool_init (
ldap_pvt_thread_pool_t *tpool,
int max_threads,
int max_pending )
{
return ldap_pvt_thread_pool_init_q( tpool, max_threads, max_pending, 1 );
}
/* Submit a task to be performed by the thread pool */
int
ldap_pvt_thread_pool_submit (
ldap_pvt_thread_pool_t *tpool,
ldap_pvt_thread_start_t *start_routine, void *arg )
{
return ldap_pvt_thread_pool_submit2( tpool, start_routine, arg, NULL );
}
/* Submit a task to be performed by the thread pool */
int
ldap_pvt_thread_pool_submit2 (
ldap_pvt_thread_pool_t *tpool,
ldap_pvt_thread_start_t *start_routine, void *arg,
void **cookie )
{
struct ldap_int_thread_pool_s *pool;
struct ldap_int_thread_poolq_s *pq;
ldap_int_thread_task_t *task;
ldap_pvt_thread_t thr;
int i, j;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
if ( pool->ltp_numqs > 1 ) {
int min = pool->ltp_wqs[0]->ltp_max_pending + pool->ltp_wqs[0]->ltp_max_count;
int min_x = 0, cnt;
for ( i = 0; i < pool->ltp_numqs; i++ ) {
/* take first queue that has nothing active */
if ( !pool->ltp_wqs[i]->ltp_active_count ) {
min_x = i;
break;
}
cnt = pool->ltp_wqs[i]->ltp_active_count + pool->ltp_wqs[i]->ltp_pending_count;
if ( cnt < min ) {
min = cnt;
min_x = i;
}
}
i = min_x;
} else
i = 0;
j = i;
while(1) {
ldap_pvt_thread_mutex_lock(&pool->ltp_wqs[i]->ltp_mutex);
if (pool->ltp_wqs[i]->ltp_pending_count < pool->ltp_wqs[i]->ltp_max_pending) {
break;
}
ldap_pvt_thread_mutex_unlock(&pool->ltp_wqs[i]->ltp_mutex);
i++;
i %= pool->ltp_numqs;
if ( i == j )
return -1;
}
pq = pool->ltp_wqs[i];
task = LDAP_SLIST_FIRST(&pq->ltp_free_list);
if (task) {
LDAP_SLIST_REMOVE_HEAD(&pq->ltp_free_list, ltt_next.l);
} else {
task = (ldap_int_thread_task_t *) LDAP_MALLOC(sizeof(*task));
if (task == NULL)
goto failed;
}
task->ltt_start_routine = start_routine;
task->ltt_arg = arg;
task->ltt_queue = pq;
if ( cookie )
*cookie = task;
pq->ltp_pending_count++;
LDAP_STAILQ_INSERT_TAIL(&pq->ltp_pending_list, task, ltt_next.q);
if (pool->ltp_pause)
goto done;
/* should we open (create) a thread? */
if (pq->ltp_open_count < pq->ltp_active_count+pq->ltp_pending_count &&
pq->ltp_open_count < pq->ltp_max_count)
{
pq->ltp_starting++;
pq->ltp_open_count++;
if (0 != ldap_pvt_thread_create(
&thr, 1, ldap_int_thread_pool_wrapper, pq))
{
/* couldn't create thread. back out of
* ltp_open_count and check for even worse things.
*/
pq->ltp_starting--;
pq->ltp_open_count--;
if (pq->ltp_open_count == 0) {
/* no open threads at all?!?
*/
ldap_int_thread_task_t *ptr;
/* let pool_destroy know there are no more threads */
ldap_pvt_thread_cond_signal(&pq->ltp_cond);
LDAP_STAILQ_FOREACH(ptr, &pq->ltp_pending_list, ltt_next.q)
if (ptr == task) break;
if (ptr == task) {
/* no open threads, task not handled, so
* back out of ltp_pending_count, free the task,
* report the error.
*/
pq->ltp_pending_count--;
LDAP_STAILQ_REMOVE(&pq->ltp_pending_list, task,
ldap_int_thread_task_s, ltt_next.q);
LDAP_SLIST_INSERT_HEAD(&pq->ltp_free_list, task,
ltt_next.l);
goto failed;
}
}
/* there is another open thread, so this
* task will be handled eventually.
*/
}
}
ldap_pvt_thread_cond_signal(&pq->ltp_cond);
done:
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
return(0);
failed:
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
return(-1);
}
static void *
no_task( void *ctx, void *arg )
{
return NULL;
}
/* Cancel a pending task that was previously submitted.
* Return 1 if the task was successfully cancelled, 0 if
* not found, -1 for invalid parameters
*/
int
ldap_pvt_thread_pool_retract (
void *cookie )
{
ldap_int_thread_task_t *task, *ttmp;
struct ldap_int_thread_poolq_s *pq;
if (cookie == NULL)
return(-1);
ttmp = cookie;
pq = ttmp->ltt_queue;
if (pq == NULL)
return(-1);
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
LDAP_STAILQ_FOREACH(task, &pq->ltp_pending_list, ltt_next.q)
if (task == ttmp) {
/* Could LDAP_STAILQ_REMOVE the task, but that
* walks ltp_pending_list again to find it.
*/
task->ltt_start_routine = no_task;
task->ltt_arg = NULL;
break;
}
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
return task != NULL;
}
/* Set number of work queues in this pool. Should not be
* more than the number of CPUs. */
int
ldap_pvt_thread_pool_queues(
ldap_pvt_thread_pool_t *tpool,
int numqs )
{
struct ldap_int_thread_pool_s *pool;
struct ldap_int_thread_poolq_s *pq;
int i, rc, rem_thr, rem_pend;
if (numqs < 1 || tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
if (numqs < pool->ltp_numqs) {
for (i=numqs; i<pool->ltp_numqs; i++)
pool->ltp_wqs[i]->ltp_max_count = 0;
} else if (numqs > pool->ltp_numqs) {
struct ldap_int_thread_poolq_s **wqs;
wqs = LDAP_REALLOC(pool->ltp_wqs, numqs * sizeof(struct ldap_int_thread_poolq_s *));
if (wqs == NULL)
return(-1);
pool->ltp_wqs = wqs;
for (i=pool->ltp_numqs; i<numqs; i++) {
char *ptr = LDAP_CALLOC(1, sizeof(struct ldap_int_thread_poolq_s) + CACHELINE-1);
if (ptr == NULL) {
for (; i<numqs; i++)
pool->ltp_wqs[i] = NULL;
return(-1);
}
pq = (struct ldap_int_thread_poolq_s *)(((size_t)ptr + CACHELINE-1) & ~(CACHELINE-1));
pq->ltp_free = ptr;
pool->ltp_wqs[i] = pq;
pq->ltp_pool = pool;
rc = ldap_pvt_thread_mutex_init(&pq->ltp_mutex);
if (rc != 0)
return(rc);
rc = ldap_pvt_thread_cond_init(&pq->ltp_cond);
if (rc != 0)
return(rc);
LDAP_STAILQ_INIT(&pq->ltp_pending_list);
pq->ltp_work_list = &pq->ltp_pending_list;
LDAP_SLIST_INIT(&pq->ltp_free_list);
}
}
rem_thr = pool->ltp_max_count % numqs;
rem_pend = pool->ltp_max_pending % numqs;
for ( i=0; i<numqs; i++ ) {
pq = pool->ltp_wqs[i];
pq->ltp_max_count = pool->ltp_max_count / numqs;
if ( rem_thr ) {
pq->ltp_max_count++;
rem_thr--;
}
pq->ltp_max_pending = pool->ltp_max_pending / numqs;
if ( rem_pend ) {
pq->ltp_max_pending++;
rem_pend--;
}
}
pool->ltp_numqs = numqs;
return 0;
}
/* Set max #threads. value <= 0 means max supported #threads (LDAP_MAXTHR) */
int
ldap_pvt_thread_pool_maxthreads(
ldap_pvt_thread_pool_t *tpool,
int max_threads )
{
struct ldap_int_thread_pool_s *pool;
struct ldap_int_thread_poolq_s *pq;
int remthr, i;
if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR))
max_threads = 0;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
pool->ltp_conf_max_count = max_threads;
if ( !max_threads )
max_threads = LDAP_MAXTHR;
pool->ltp_max_count = max_threads;
remthr = max_threads % pool->ltp_numqs;
max_threads /= pool->ltp_numqs;
for (i=0; i<pool->ltp_numqs; i++) {
pq = pool->ltp_wqs[i];
pq->ltp_max_count = max_threads;
if (remthr) {
pq->ltp_max_count++;
remthr--;
}
}
return(0);
}
/* Inspect the pool */
int
ldap_pvt_thread_pool_query(
ldap_pvt_thread_pool_t *tpool,
ldap_pvt_thread_pool_param_t param,
void *value )
{
struct ldap_int_thread_pool_s *pool;
int count = -1;
if ( tpool == NULL || value == NULL ) {
return -1;
}
pool = *tpool;
if ( pool == NULL ) {
return 0;
}
switch ( param ) {
case LDAP_PVT_THREAD_POOL_PARAM_MAX:
count = pool->ltp_conf_max_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_MAX_PENDING:
count = pool->ltp_max_pending;
if (count < 0)
count = -count;
if (count == MAX_PENDING)
count = 0;
break;
case LDAP_PVT_THREAD_POOL_PARAM_PAUSING:
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
count = (pool->ltp_pause != 0);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
break;
case LDAP_PVT_THREAD_POOL_PARAM_OPEN:
case LDAP_PVT_THREAD_POOL_PARAM_STARTING:
case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE:
case LDAP_PVT_THREAD_POOL_PARAM_PENDING:
case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD:
{
int i;
count = 0;
for (i=0; i<pool->ltp_numqs; i++) {
struct ldap_int_thread_poolq_s *pq = pool->ltp_wqs[i];
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
switch(param) {
case LDAP_PVT_THREAD_POOL_PARAM_OPEN:
count += pq->ltp_open_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_STARTING:
count += pq->ltp_starting;
break;
case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE:
count += pq->ltp_active_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_PENDING:
count += pq->ltp_pending_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD:
count += pq->ltp_pending_count + pq->ltp_active_count;
break;
}
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
}
if (count < 0)
count = -count;
}
break;
case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE_MAX:
break;
case LDAP_PVT_THREAD_POOL_PARAM_PENDING_MAX:
break;
case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD_MAX:
break;
case LDAP_PVT_THREAD_POOL_PARAM_STATE:
if (pool->ltp_pause)
*((char **)value) = "pausing";
else if (!pool->ltp_finishing)
*((char **)value) = "running";
else {
int i;
for (i=0; i<pool->ltp_numqs; i++)
if (pool->ltp_wqs[i]->ltp_pending_count) break;
if (i<pool->ltp_numqs)
*((char **)value) = "finishing";
else
*((char **)value) = "stopping";
}
break;
case LDAP_PVT_THREAD_POOL_PARAM_UNKNOWN:
break;
}
if ( count > -1 ) {
*((int *)value) = count;
}
return ( count == -1 ? -1 : 0 );
}
/*
* true if pool is pausing; does not lock any mutex to check.
* 0 if not pause, 1 if pause, -1 if error or no pool.
*/
int
ldap_pvt_thread_pool_pausing( ldap_pvt_thread_pool_t *tpool )
{
int rc = -1;
struct ldap_int_thread_pool_s *pool;
if ( tpool != NULL && (pool = *tpool) != NULL ) {
rc = (pool->ltp_pause != 0);
}
return rc;
}
/*
* wrapper for ldap_pvt_thread_pool_query(), left around
* for backwards compatibility
*/
int
ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
{
int rc, count;
rc = ldap_pvt_thread_pool_query( tpool,
LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD, (void *)&count );
if ( rc == 0 ) {
return count;
}
return rc;
}
/* Destroy the pool after making its threads finish */
int
ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
{
struct ldap_int_thread_pool_s *pool, *pptr;
struct ldap_int_thread_poolq_s *pq;
ldap_int_thread_task_t *task;
int i;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL) return(-1);
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
if (pptr == pool) break;
if (pptr == pool)
LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
ldap_int_thread_pool_s, ltp_next);
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
if (pool != pptr) return(-1);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool->ltp_finishing = 1;
if (pool->ltp_max_pending > 0)
pool->ltp_max_pending = -pool->ltp_max_pending;
ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
for (i=0; i<pool->ltp_numqs; i++) {
pq = pool->ltp_wqs[i];
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
if (pq->ltp_max_pending > 0)
pq->ltp_max_pending = -pq->ltp_max_pending;
if (!run_pending) {
while ((task = LDAP_STAILQ_FIRST(&pq->ltp_pending_list)) != NULL) {
LDAP_STAILQ_REMOVE_HEAD(&pq->ltp_pending_list, ltt_next.q);
LDAP_FREE(task);
}
pq->ltp_pending_count = 0;
}
while (pq->ltp_open_count) {
ldap_pvt_thread_cond_broadcast(&pq->ltp_cond);
ldap_pvt_thread_cond_wait(&pq->ltp_cond, &pq->ltp_mutex);
}
while ((task = LDAP_SLIST_FIRST(&pq->ltp_free_list)) != NULL)
{
LDAP_SLIST_REMOVE_HEAD(&pq->ltp_free_list, ltt_next.l);
LDAP_FREE(task);
}
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
ldap_pvt_thread_cond_destroy(&pq->ltp_cond);
ldap_pvt_thread_mutex_destroy(&pq->ltp_mutex);
}
ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
for (i=0; i<pool->ltp_numqs; i++) {
pq = pool->ltp_wqs[i];
if (pq->ltp_free) {
LDAP_FREE(pq->ltp_free);
}
}
LDAP_FREE(pool->ltp_wqs);
LDAP_FREE(pool);
*tpool = NULL;
ldap_int_has_thread_pool = 0;
return(0);
}
/* Thread loop. Accept and handle submitted tasks. */
static void *
ldap_int_thread_pool_wrapper (
void *xpool )
{
struct ldap_int_thread_poolq_s *pq = xpool;
struct ldap_int_thread_pool_s *pool = pq->ltp_pool;
ldap_int_thread_task_t *task;
ldap_int_tpool_plist_t *work_list;
ldap_int_thread_userctx_t ctx, *kctx;
unsigned i, keyslot, hash;
int pool_lock = 0, freeme = 0;
assert(pool != NULL);
for ( i=0; i<MAXKEYS; i++ ) {
ctx.ltu_key[i].ltk_key = NULL;
}
ctx.ltu_pq = pq;
ctx.ltu_id = ldap_pvt_thread_self();
TID_HASH(ctx.ltu_id, hash);
ldap_pvt_thread_key_setdata( ldap_tpool_key, &ctx );
if (pool->ltp_pause) {
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
/* thread_keys[] is read-only when paused */
while (pool->ltp_pause)
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
}
/* find a key slot to give this thread ID and store a
* pointer to our keys there; start at the thread ID
* itself (mod LDAP_MAXTHR) and look for an empty slot.
*/
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
for (keyslot = hash & (LDAP_MAXTHR-1);
(kctx = thread_keys[keyslot].ctx) && kctx != DELETED_THREAD_CTX;
keyslot = (keyslot+1) & (LDAP_MAXTHR-1));
thread_keys[keyslot].ctx = &ctx;
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
pq->ltp_starting--;
pq->ltp_active_count++;
for (;;) {
work_list = pq->ltp_work_list; /* help the compiler a bit */
task = LDAP_STAILQ_FIRST(work_list);
if (task == NULL) { /* paused or no pending tasks */
if (--(pq->ltp_active_count) < 1) {
if (pool->ltp_pause) {
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool_lock = 1;
if (--(pool->ltp_active_queues) < 1) {
/* Notify pool_pause it is the sole active thread. */
ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
}
}
}
do {
if (pool->ltp_finishing || pq->ltp_open_count > pq->ltp_max_count) {
/* Not paused, and either finishing or too many
* threads running (can happen if ltp_max_count
* was reduced). Let this thread die.
*/
goto done;
}
/* We could check an idle timer here, and let the
* thread die if it has been inactive for a while.
* Only die if there are other open threads (i.e.,
* always have at least one thread open).
* The check should be like this:
* if (pool->ltp_open_count>1 && pool->ltp_starting==0)
* check timer, wait if ltp_pause, leave thread;
*
* Just use pthread_cond_timedwait() if we want to
* check idle time.
*/
if (pool_lock) {
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
if (!pool->ltp_pause) {
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
pool_lock = 0;
}
} else
ldap_pvt_thread_cond_wait(&pq->ltp_cond, &pq->ltp_mutex);
work_list = pq->ltp_work_list;
task = LDAP_STAILQ_FIRST(work_list);
} while (task == NULL);
if (pool_lock) {
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
pool_lock = 0;
}
pq->ltp_active_count++;
}
LDAP_STAILQ_REMOVE_HEAD(work_list, ltt_next.q);
pq->ltp_pending_count--;
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
task->ltt_start_routine(&ctx, task->ltt_arg);
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
LDAP_SLIST_INSERT_HEAD(&pq->ltp_free_list, task, ltt_next.l);
}
done:
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
/* The pool_mutex lock protects ctx->ltu_key from pool_purgekey()
* during this call, since it prevents new pauses. */
ldap_pvt_thread_pool_context_reset(&ctx);
thread_keys[keyslot].ctx = DELETED_THREAD_CTX;
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
pq->ltp_open_count--;
if (pq->ltp_open_count == 0) {
if (pool->ltp_finishing)
/* let pool_destroy know we're all done */
ldap_pvt_thread_cond_signal(&pq->ltp_cond);
else
freeme = 1;
}
if (pool_lock)
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
else
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
if (freeme) {
ldap_pvt_thread_cond_destroy(&pq->ltp_cond);
ldap_pvt_thread_mutex_destroy(&pq->ltp_mutex);
LDAP_FREE(pq->ltp_free);
pq->ltp_free = NULL;
}
ldap_pvt_thread_exit(NULL);
return(NULL);
}
/* Arguments > ltp_pause to handle_pause(,PAUSE_ARG()). arg=PAUSE_ARG
* ensures (arg-ltp_pause) sets GO_* at need and keeps DO_PAUSE/GO_*.
*/
#define GO_IDLE 8
#define GO_UNIDLE 16
#define CHECK_PAUSE 32 /* if ltp_pause: GO_IDLE; wait; GO_UNIDLE */
#define DO_PAUSE 64 /* CHECK_PAUSE; pause the pool */
#define PAUSE_ARG(a) \
((a) | ((a) & (GO_IDLE|GO_UNIDLE) ? GO_IDLE-1 : CHECK_PAUSE))
static int
handle_pause( ldap_pvt_thread_pool_t *tpool, int pause_type )
{
struct ldap_int_thread_pool_s *pool;
struct ldap_int_thread_poolq_s *pq;
int ret = 0, pause, max_ltp_pause;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(0);
if (pause_type == CHECK_PAUSE && !pool->ltp_pause)
return(0);
{
ldap_int_thread_userctx_t *ctx = ldap_pvt_thread_pool_context();
pq = ctx->ltu_pq;
if ( !pq )
return(-1);
}
/* Let pool_unidle() ignore requests for new pauses */
max_ltp_pause = pause_type==PAUSE_ARG(GO_UNIDLE) ? WANT_PAUSE : NOT_PAUSED;
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pause = pool->ltp_pause; /* NOT_PAUSED, WANT_PAUSE or PAUSED */
/* If ltp_pause and not GO_IDLE|GO_UNIDLE: Set GO_IDLE,GO_UNIDLE */
pause_type -= pause;
if (pause_type & GO_IDLE) {
int do_pool = 0;
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
pq->ltp_pending_count++;
pq->ltp_active_count--;
if (pause && pq->ltp_active_count < 1) {
do_pool = 1;
}
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
if (do_pool) {
pool->ltp_active_queues--;
if (pool->ltp_active_queues < 1)
/* Tell the task waiting to DO_PAUSE it can proceed */
ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
}
}
if (pause_type & GO_UNIDLE) {
/* Wait out pause if any, then cancel GO_IDLE */
if (pause > max_ltp_pause) {
ret = 1;
do {
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
} while (pool->ltp_pause > max_ltp_pause);
}
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
pq->ltp_pending_count--;
pq->ltp_active_count++;
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
}
if (pause_type & DO_PAUSE) {
int i, j;
/* Tell everyone else to pause or finish, then await that */
ret = 0;
assert(!pool->ltp_pause);
pool->ltp_pause = WANT_PAUSE;
pool->ltp_active_queues = 0;
for (i=0; i<pool->ltp_numqs; i++)
if (pool->ltp_wqs[i] == pq) break;
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
/* temporarily remove ourself from active count */
pq->ltp_active_count--;
j=i;
do {
pq = pool->ltp_wqs[j];
if (j != i)
ldap_pvt_thread_mutex_lock(&pq->ltp_mutex);
/* Hide pending tasks from ldap_pvt_thread_pool_wrapper() */
pq->ltp_work_list = &empty_pending_list;
if (pq->ltp_active_count > 0)
pool->ltp_active_queues++;
ldap_pvt_thread_mutex_unlock(&pq->ltp_mutex);
if (pool->ltp_numqs > 1) {
j++;
j %= pool->ltp_numqs;
}
} while (j != i);
/* Wait for this task to become the sole active task */
while (pool->ltp_active_queues > 0)
ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
/* restore us to active count */
pool->ltp_wqs[i]->ltp_active_count++;
assert(pool->ltp_pause == WANT_PAUSE);
pool->ltp_pause = PAUSED;
}
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(ret);
}
/* Consider this task idle: It will not block pool_pause() in other tasks. */
void
ldap_pvt_thread_pool_idle( ldap_pvt_thread_pool_t *tpool )
{
handle_pause(tpool, PAUSE_ARG(GO_IDLE));
}
/* Cancel pool_idle(). If the pool is paused, wait it out first. */
void
ldap_pvt_thread_pool_unidle( ldap_pvt_thread_pool_t *tpool )
{
handle_pause(tpool, PAUSE_ARG(GO_UNIDLE));
}
/*
* If a pause was requested, wait for it. If several threads
* are waiting to pause, let through one or more pauses.
* The calling task must be active, not idle.
* Return 1 if we waited, 0 if not, -1 at parameter error.
*/
int
ldap_pvt_thread_pool_pausecheck( ldap_pvt_thread_pool_t *tpool )
{
return handle_pause(tpool, PAUSE_ARG(CHECK_PAUSE));
}
/*
* Pause the pool. The calling task must be active, not idle.
* Return when all other tasks are paused or idle.
*/
int
ldap_pvt_thread_pool_pause( ldap_pvt_thread_pool_t *tpool )
{
return handle_pause(tpool, PAUSE_ARG(DO_PAUSE));
}
/* End a pause */
int
ldap_pvt_thread_pool_resume (
ldap_pvt_thread_pool_t *tpool )
{
struct ldap_int_thread_pool_s *pool;
struct ldap_int_thread_poolq_s *pq;
int i;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(0);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
assert(pool->ltp_pause == PAUSED);
pool->ltp_pause = 0;
for (i=0; i<pool->ltp_numqs; i++) {
pq = pool->ltp_wqs[i];
pq->ltp_work_list = &pq->ltp_pending_list;
ldap_pvt_thread_cond_broadcast(&pq->ltp_cond);
}
ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(0);
}
/*
* Get the key's data and optionally free function in the given context.
*/
int ldap_pvt_thread_pool_getkey(
void *xctx,
void *key,
void **data,
ldap_pvt_thread_pool_keyfree_t **kfree )
{
ldap_int_thread_userctx_t *ctx = xctx;
int i;
if ( !ctx || !key || !data ) return EINVAL;
for ( i=0; i<MAXKEYS && ctx->ltu_key[i].ltk_key; i++ ) {
if ( ctx->ltu_key[i].ltk_key == key ) {
*data = ctx->ltu_key[i].ltk_data;
if ( kfree ) *kfree = ctx->ltu_key[i].ltk_free;
return 0;
}
}
return ENOENT;
}
static void
clear_key_idx( ldap_int_thread_userctx_t *ctx, int i )
{
for ( ; i < MAXKEYS-1 && ctx->ltu_key[i+1].ltk_key; i++ )
ctx->ltu_key[i] = ctx->ltu_key[i+1];
ctx->ltu_key[i].ltk_key = NULL;
}
/*
* Set or remove data for the key in the given context.
* key can be any unique pointer.
* kfree() is an optional function to free the data (but not the key):
* pool_context_reset() and pool_purgekey() call kfree(key, data),
* but pool_setkey() does not. For pool_setkey() it is the caller's
* responsibility to free any existing data with the same key.
* kfree() must not call functions taking a tpool argument.
*/
int ldap_pvt_thread_pool_setkey(
void *xctx,
void *key,
void *data,
ldap_pvt_thread_pool_keyfree_t *kfree,
void **olddatap,
ldap_pvt_thread_pool_keyfree_t **oldkfreep )
{
ldap_int_thread_userctx_t *ctx = xctx;
int i, found;
if ( !ctx || !key ) return EINVAL;
for ( i=found=0; i<MAXKEYS; i++ ) {
if ( ctx->ltu_key[i].ltk_key == key ) {
found = 1;
break;
} else if ( !ctx->ltu_key[i].ltk_key ) {
break;
}
}
if ( olddatap ) {
if ( found ) {
*olddatap = ctx->ltu_key[i].ltk_data;
} else {
*olddatap = NULL;
}
}
if ( oldkfreep ) {
if ( found ) {
*oldkfreep = ctx->ltu_key[i].ltk_free;
} else {
*oldkfreep = 0;
}
}
if ( data || kfree ) {
if ( i>=MAXKEYS )
return ENOMEM;
ctx->ltu_key[i].ltk_key = key;
ctx->ltu_key[i].ltk_data = data;
ctx->ltu_key[i].ltk_free = kfree;
} else if ( found ) {
clear_key_idx( ctx, i );
}
return 0;
}
/* Free all elements with this key, no matter which thread they're in.
* May only be called while the pool is paused.
*/
void ldap_pvt_thread_pool_purgekey( void *key )
{
int i, j;
ldap_int_thread_userctx_t *ctx;
assert ( key != NULL );
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
for ( i=0; i<LDAP_MAXTHR; i++ ) {
ctx = thread_keys[i].ctx;
if ( ctx && ctx != DELETED_THREAD_CTX ) {
for ( j=0; j<MAXKEYS && ctx->ltu_key[j].ltk_key; j++ ) {
if ( ctx->ltu_key[j].ltk_key == key ) {
if (ctx->ltu_key[j].ltk_free)
ctx->ltu_key[j].ltk_free( ctx->ltu_key[j].ltk_key,
ctx->ltu_key[j].ltk_data );
clear_key_idx( ctx, j );
break;
}
}
}
}
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
}
/*
* Find the context of the current thread.
* This is necessary if the caller does not have access to the
* thread context handle (for example, a slapd plugin calling
* slapi_search_internal()). No doubt it is more efficient
* for the application to keep track of the thread context
* handles itself.
*/
void *ldap_pvt_thread_pool_context( )
{
void *ctx = NULL;
ldap_pvt_thread_key_getdata( ldap_tpool_key, &ctx );
return ctx ? ctx : (void *) &ldap_int_main_thrctx;
}
/*
* Free the context's keys.
* Must not call functions taking a tpool argument (because this
* thread already holds ltp_mutex when called from pool_wrapper()).
*/
void ldap_pvt_thread_pool_context_reset( void *vctx )
{
ldap_int_thread_userctx_t *ctx = vctx;
int i;
for ( i=MAXKEYS-1; i>=0; i--) {
if ( !ctx->ltu_key[i].ltk_key )
continue;
if ( ctx->ltu_key[i].ltk_free )
ctx->ltu_key[i].ltk_free( ctx->ltu_key[i].ltk_key,
ctx->ltu_key[i].ltk_data );
ctx->ltu_key[i].ltk_key = NULL;
}
}
ldap_pvt_thread_t ldap_pvt_thread_pool_tid( void *vctx )
{
ldap_int_thread_userctx_t *ctx = vctx;
return ctx->ltu_id;
}
#endif /* LDAP_THREAD_HAVE_TPOOL */