openldap/libraries/libldap_r/tpool.c
Hallvard Furuseth 671bed5270 Cleanup & slight speedup (no real change):
Remove '#if 0 / broken code / #endif.  Rearrange pool_wrapper() to avoid
decrement-increment(ltp_active_count) when more tasks available.
2009-06-12 20:46:36 +00:00

974 lines
25 KiB
C

/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 1998-2009 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
/* 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) */
/* Context: thread ID and thread-specific key/data pairs */
typedef struct ldap_int_thread_userctx_s {
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 except during pauses,
* when it is read-only (used by pool_purgekey and pool_context).
* Protected by tpool->ltp_mutex during pauses.
*/
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;
} ldap_int_thread_task_t;
typedef LDAP_STAILQ_HEAD(tcq, ldap_int_thread_task_s) ldap_int_tpool_plist_t;
struct ldap_int_thread_pool_s {
LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
/* protect members below, and protect thread_keys[] during pauses */
ldap_pvt_thread_mutex_t ltp_mutex;
/* not paused and something to do for pool_<wrapper/pause/destroy>() */
ldap_pvt_thread_cond_t ltp_cond;
/* ltp_active_count <= 1 && ltp_pause */
ldap_pvt_thread_cond_t ltp_pcond;
/* 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;
/* 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.
* Note: Pauses adjust ltp_<open_count/vary_open_count/work_list>,
* so pool_<submit/wrapper>() mostly can avoid testing ltp_pause.
*/
volatile sig_atomic_t ltp_pause;
/* Max number of threads in pool, or 0 for default (LDAP_MAXTHR) */
int ltp_max_count;
/* Max number of pending + paused requests, negated when ltp_finishing */
int ltp_max_pending;
int ltp_pending_count; /* Pending or paused requests */
int ltp_active_count; /* Active, not paused requests */
int ltp_open_count; /* Number of threads, negated when ltp_pause */
int ltp_starting; /* Currenlty starting threads */
/* >0 if paused or we may open a thread, <0 if we should close a thread.
* Updated when ltp_<finishing/pause/max_count/open_count> change.
* Maintained to reduce the time ltp_mutex must be locked in
* ldap_pvt_thread_pool_<submit/wrapper>().
*/
int ltp_vary_open_count;
# define SET_VARY_OPEN_COUNT(pool) \
((pool)->ltp_vary_open_count = \
(pool)->ltp_pause ? 1 : \
(pool)->ltp_finishing ? -1 : \
((pool)->ltp_max_count ? (pool)->ltp_max_count : LDAP_MAXTHR) \
- (pool)->ltp_open_count)
};
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 (
ldap_pvt_thread_pool_t *tpool,
int max_threads,
int max_pending )
{
ldap_pvt_thread_pool_t pool;
int rc;
/* 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);
rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex);
if (rc != 0)
return(rc);
rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
if (rc != 0)
return(rc);
rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
if (rc != 0)
return(rc);
ldap_int_has_thread_pool = 1;
pool->ltp_max_count = max_threads;
SET_VARY_OPEN_COUNT(pool);
pool->ltp_max_pending = max_pending;
LDAP_STAILQ_INIT(&pool->ltp_pending_list);
pool->ltp_work_list = &pool->ltp_pending_list;
LDAP_SLIST_INIT(&pool->ltp_free_list);
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);
}
/* 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 )
{
struct ldap_int_thread_pool_s *pool;
ldap_int_thread_task_t *task;
ldap_pvt_thread_t thr;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
if (pool->ltp_pending_count >= pool->ltp_max_pending)
goto failed;
task = LDAP_SLIST_FIRST(&pool->ltp_free_list);
if (task) {
LDAP_SLIST_REMOVE_HEAD(&pool->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;
pool->ltp_pending_count++;
LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, task, ltt_next.q);
/* true if ltp_pause != 0 or we should open (create) a thread */
if (pool->ltp_vary_open_count > 0 &&
pool->ltp_open_count < pool->ltp_active_count+pool->ltp_pending_count)
{
if (pool->ltp_pause)
goto done;
pool->ltp_starting++;
pool->ltp_open_count++;
SET_VARY_OPEN_COUNT(pool);
if (0 != ldap_pvt_thread_create(
&thr, 1, ldap_int_thread_pool_wrapper, pool))
{
/* couldn't create thread. back out of
* ltp_open_count and check for even worse things.
*/
pool->ltp_starting--;
pool->ltp_open_count--;
SET_VARY_OPEN_COUNT(pool);
if (pool->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(&pool->ltp_cond);
LDAP_STAILQ_FOREACH(ptr, &pool->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.
*/
pool->ltp_pending_count--;
LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, task,
ldap_int_thread_task_s, ltt_next.q);
LDAP_SLIST_INSERT_HEAD(&pool->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(&pool->ltp_cond);
done:
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(0);
failed:
ldap_pvt_thread_mutex_unlock(&pool->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 (
ldap_pvt_thread_pool_t *tpool,
ldap_pvt_thread_start_t *start_routine, void *arg )
{
struct ldap_int_thread_pool_s *pool;
ldap_int_thread_task_t *task;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
LDAP_STAILQ_FOREACH(task, &pool->ltp_pending_list, ltt_next.q)
if (task->ltt_start_routine == start_routine &&
task->ltt_arg == arg) {
/* 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(&pool->ltp_mutex);
return task != NULL;
}
/* 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;
if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR))
max_threads = 0;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(-1);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
pool->ltp_max_count = max_threads;
SET_VARY_OPEN_COUNT(pool);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
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;
}
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
switch ( param ) {
case LDAP_PVT_THREAD_POOL_PARAM_MAX:
count = pool->ltp_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_OPEN:
count = pool->ltp_open_count;
if (count < 0)
count = -count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_STARTING:
count = pool->ltp_starting;
break;
case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE:
count = pool->ltp_active_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_PAUSING:
count = pool->ltp_pause;
break;
case LDAP_PVT_THREAD_POOL_PARAM_PENDING:
count = pool->ltp_pending_count;
break;
case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD:
count = pool->ltp_pending_count + pool->ltp_active_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:
*((char **)value) =
pool->ltp_pause ? "pausing" :
!pool->ltp_finishing ? "running" :
pool->ltp_pending_count ? "finishing" : "stopping";
break;
case LDAP_PVT_THREAD_POOL_PARAM_UNKNOWN:
break;
}
ldap_pvt_thread_mutex_unlock( &pool->ltp_mutex );
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;
}
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;
ldap_int_thread_task_t *task;
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;
SET_VARY_OPEN_COUNT(pool);
if (pool->ltp_max_pending > 0)
pool->ltp_max_pending = -pool->ltp_max_pending;
if (!run_pending) {
while ((task = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL) {
LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltt_next.q);
LDAP_FREE(task);
}
pool->ltp_pending_count = 0;
}
while (pool->ltp_open_count) {
if (!pool->ltp_pause)
ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
}
while ((task = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
{
LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltt_next.l);
LDAP_FREE(task);
}
ldap_pvt_thread_mutex_unlock(&pool->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);
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_pool_s *pool = xpool;
ldap_int_thread_task_t *task;
ldap_int_tpool_plist_t *work_list;
ldap_int_thread_userctx_t ctx, *kctx;
unsigned i, keyslot, hash;
assert(pool != NULL);
for ( i=0; i<MAXKEYS; i++ ) {
ctx.ltu_key[i].ltk_key = NULL;
}
ctx.ltu_id = ldap_pvt_thread_self();
TID_HASH(ctx.ltu_id, hash);
ldap_pvt_thread_key_setdata( ldap_tpool_key, &ctx );
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);
/* 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);
pool->ltp_starting--;
pool->ltp_active_count++;
for (;;) {
work_list = pool->ltp_work_list; /* help the compiler a bit */
task = LDAP_STAILQ_FIRST(work_list);
if (task == NULL) { /* paused or no pending tasks */
if (--(pool->ltp_active_count) < 2) {
/* Notify pool_pause it is the sole active thread. */
ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
}
do {
if (pool->ltp_vary_open_count < 0) {
/* 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.
*/
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
work_list = pool->ltp_work_list;
task = LDAP_STAILQ_FIRST(work_list);
} while (task == NULL);
pool->ltp_active_count++;
}
LDAP_STAILQ_REMOVE_HEAD(work_list, ltt_next.q);
pool->ltp_pending_count--;
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
task->ltt_start_routine(&ctx, task->ltt_arg);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task, ltt_next.l);
}
done:
assert(!pool->ltp_pause); /* thread_keys writable, ltp_open_count >= 0 */
/* The ltp_mutex lock protects ctx->ltu_key from pool_purgekey()
* during this call, since it prevents new pauses. */
ldap_pvt_thread_pool_context_reset(&ctx);
ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
thread_keys[keyslot].ctx = DELETED_THREAD_CTX;
ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
pool->ltp_open_count--;
SET_VARY_OPEN_COUNT(pool);
/* let pool_destroy know we're all done */
if (pool->ltp_open_count == 0)
ldap_pvt_thread_cond_signal(&pool->ltp_cond);
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
ldap_pvt_thread_exit(NULL);
return(NULL);
}
static int
handle_pause( ldap_pvt_thread_pool_t *tpool, int do_pause )
{
struct ldap_int_thread_pool_s *pool;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(0);
if (! (do_pause || pool->ltp_pause))
return(0);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
/* If someone else has already requested a pause, we have to wait */
if (pool->ltp_pause) {
pool->ltp_pending_count++;
pool->ltp_active_count--;
/* let the other pool_pause() know when it can proceed */
if (pool->ltp_active_count < 2)
ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
do {
ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
} while (pool->ltp_pause);
pool->ltp_pending_count--;
pool->ltp_active_count++;
}
if (do_pause) {
/* Wait for everyone else to pause or finish */
pool->ltp_pause = 1;
/* Let ldap_pvt_thread_pool_submit() through to its ltp_pause test,
* and do not finish threads in ldap_pvt_thread_pool_wrapper() */
pool->ltp_open_count = -pool->ltp_open_count;
SET_VARY_OPEN_COUNT(pool);
/* Hide pending tasks from ldap_pvt_thread_pool_wrapper() */
pool->ltp_work_list = &empty_pending_list;
while (pool->ltp_active_count > 1) {
ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
}
}
ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
return(!do_pause);
}
/*
* If a pause was requested, wait for it. If several threads
* are waiting to pause, let through one or more pauses.
* 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, 0 );
}
/* Pause the pool. Return when all other threads are paused. */
int
ldap_pvt_thread_pool_pause( ldap_pvt_thread_pool_t *tpool )
{
return handle_pause( tpool, 1 );
}
/* End a pause */
int
ldap_pvt_thread_pool_resume (
ldap_pvt_thread_pool_t *tpool )
{
struct ldap_int_thread_pool_s *pool;
if (tpool == NULL)
return(-1);
pool = *tpool;
if (pool == NULL)
return(0);
ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
assert(pool->ltp_pause);
pool->ltp_pause = 0;
if (pool->ltp_open_count <= 0) /* true when paused, but be paranoid */
pool->ltp_open_count = -pool->ltp_open_count;
SET_VARY_OPEN_COUNT(pool);
pool->ltp_work_list = &pool->ltp_pending_list;
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 );
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;
}
}
}
}
}
/*
* 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 */