X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=glib%2Fgthreadpool.c;h=de9cedf00fa3f63f1c92b66352dc5552a75f36b1;hb=14f2376c8a06f0936d734ec6a7e0e836072acf65;hp=c2620ccbc96ccf0d21a4ad661694ad1ca4333ba3;hpb=227d18bc469fb00c8c506121c0ae30b453991407;p=platform%2Fupstream%2Fglib.git diff --git a/glib/gthreadpool.c b/glib/gthreadpool.c index c2620cc..de9cedf 100644 --- a/glib/gthreadpool.c +++ b/glib/gthreadpool.c @@ -1,7 +1,7 @@ /* GLIB - Library of useful routines for C programming * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald * - * GAsyncQueue: thread pool implementation. + * GThreadPool: thread pool implementation. * Copyright (C) 2000 Sebastian Wilhelmi; University of Karlsruhe * * This library is free software; you can redistribute it and/or @@ -15,199 +15,379 @@ * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the - * Free Software Foundation, Inc., 59 Temple Place - Suite 330, - * Boston, MA 02111-1307, USA. + * License along with this library; if not, see . */ /* * MT safe */ -#include "glib.h" +#include "config.h" + +#include "gthreadpool.h" + +#include "gasyncqueue.h" +#include "gasyncqueueprivate.h" +#include "gmain.h" +#include "gtestutils.h" +#include "gtimer.h" + +/** + * SECTION:thread_pools + * @title: Thread Pools + * @short_description: pools of threads to execute work concurrently + * @see_also: #GThread + * + * Sometimes you wish to asynchronously fork out the execution of work + * and continue working in your own thread. If that will happen often, + * the overhead of starting and destroying a thread each time might be + * too high. In such cases reusing already started threads seems like a + * good idea. And it indeed is, but implementing this can be tedious + * and error-prone. + * + * Therefore GLib provides thread pools for your convenience. An added + * advantage is, that the threads can be shared between the different + * subsystems of your program, when they are using GLib. + * + * To create a new thread pool, you use g_thread_pool_new(). + * It is destroyed by g_thread_pool_free(). + * + * If you want to execute a certain task within a thread pool, + * you call g_thread_pool_push(). + * + * To get the current number of running threads you call + * g_thread_pool_get_num_threads(). To get the number of still + * unprocessed tasks you call g_thread_pool_unprocessed(). To control + * the maximal number of threads for a thread pool, you use + * g_thread_pool_get_max_threads() and g_thread_pool_set_max_threads(). + * + * Finally you can control the number of unused threads, that are kept + * alive by GLib for future use. The current number can be fetched with + * g_thread_pool_get_num_unused_threads(). The maximal number can be + * controlled by g_thread_pool_get_max_unused_threads() and + * g_thread_pool_set_max_unused_threads(). All currently unused threads + * can be stopped by calling g_thread_pool_stop_unused_threads(). + */ + +#define DEBUG_MSG(x) +/* #define DEBUG_MSG(args) g_printerr args ; g_printerr ("\n"); */ typedef struct _GRealThreadPool GRealThreadPool; +/** + * GThreadPool: + * @func: the function to execute in the threads of this pool + * @user_data: the user data for the threads of this pool + * @exclusive: are all threads exclusive to this pool + * + * The #GThreadPool struct represents a thread pool. It has three + * public read-only members, but the underlying struct is bigger, + * so you must not copy this struct. + */ struct _GRealThreadPool { GThreadPool pool; - GAsyncQueue* queue; + GAsyncQueue *queue; + GCond cond; gint max_threads; gint num_threads; gboolean running; gboolean immediate; gboolean waiting; + GCompareDataFunc sort_func; + gpointer sort_user_data; }; -/* The following is just an address to mark the stop order for a +/* The following is just an address to mark the wakeup order for a * thread, it could be any address (as long, as it isn't a valid - * GThreadPool address) */ -static const gpointer stop_this_thread_marker = (gpointer) &g_thread_pool_new; + * GThreadPool address) + */ +static const gpointer wakeup_thread_marker = (gpointer) &g_thread_pool_new; +static gint wakeup_thread_serial = 0; /* Here all unused threads are waiting */ -static GAsyncQueue *unused_thread_queue; +static GAsyncQueue *unused_thread_queue = NULL; static gint unused_threads = 0; -static gint max_unused_threads = 0; -G_LOCK_DEFINE_STATIC (unused_threads); +static gint max_unused_threads = 2; +static gint kill_unused_threads = 0; +static guint max_idle_time = 15 * 1000; + +static void g_thread_pool_queue_push_unlocked (GRealThreadPool *pool, + gpointer data); +static void g_thread_pool_free_internal (GRealThreadPool *pool); +static gpointer g_thread_pool_thread_proxy (gpointer data); +static gboolean g_thread_pool_start_thread (GRealThreadPool *pool, + GError **error); +static void g_thread_pool_wakeup_and_stop_all (GRealThreadPool *pool); +static GRealThreadPool* g_thread_pool_wait_for_new_pool (void); +static gpointer g_thread_pool_wait_for_new_task (GRealThreadPool *pool); -static GMutex *inform_mutex = NULL; -static GCond *inform_cond = NULL; +static void +g_thread_pool_queue_push_unlocked (GRealThreadPool *pool, + gpointer data) +{ + if (pool->sort_func) + g_async_queue_push_sorted_unlocked (pool->queue, + data, + pool->sort_func, + pool->sort_user_data); + else + g_async_queue_push_unlocked (pool->queue, data); +} -static void g_thread_pool_free_internal (GRealThreadPool* pool); -static gpointer g_thread_pool_thread_proxy (gpointer data); -static void g_thread_pool_start_thread (GRealThreadPool* pool, - GError **error); -static void g_thread_pool_wakeup_and_stop_all (GRealThreadPool* pool); +static GRealThreadPool* +g_thread_pool_wait_for_new_pool (void) +{ + GRealThreadPool *pool; + gint local_wakeup_thread_serial; + guint local_max_unused_threads; + gint local_max_idle_time; + gint last_wakeup_thread_serial; + gboolean have_relayed_thread_marker = FALSE; -#define g_thread_should_run(pool, len) \ - ((pool)->running || (!(pool)->immediate && (len) > 0)) + local_max_unused_threads = g_atomic_int_get (&max_unused_threads); + local_max_idle_time = g_atomic_int_get (&max_idle_time); + last_wakeup_thread_serial = g_atomic_int_get (&wakeup_thread_serial); -static gpointer + g_atomic_int_inc (&unused_threads); + + do + { + if (g_atomic_int_get (&unused_threads) >= local_max_unused_threads) + { + /* If this is a superfluous thread, stop it. */ + pool = NULL; + } + else if (local_max_idle_time > 0) + { + /* If a maximal idle time is given, wait for the given time. */ + DEBUG_MSG (("thread %p waiting in global pool for %f seconds.", + g_thread_self (), local_max_idle_time / 1000.0)); + + pool = g_async_queue_timeout_pop (unused_thread_queue, + local_max_idle_time * 1000); + } + else + { + /* If no maximal idle time is given, wait indefinitely. */ + DEBUG_MSG (("thread %p waiting in global pool.", g_thread_self ())); + pool = g_async_queue_pop (unused_thread_queue); + } + + if (pool == wakeup_thread_marker) + { + local_wakeup_thread_serial = g_atomic_int_get (&wakeup_thread_serial); + if (last_wakeup_thread_serial == local_wakeup_thread_serial) + { + if (!have_relayed_thread_marker) + { + /* If this wakeup marker has been received for + * the second time, relay it. + */ + DEBUG_MSG (("thread %p relaying wakeup message to " + "waiting thread with lower serial.", + g_thread_self ())); + + g_async_queue_push (unused_thread_queue, wakeup_thread_marker); + have_relayed_thread_marker = TRUE; + + /* If a wakeup marker has been relayed, this thread + * will get out of the way for 100 microseconds to + * avoid receiving this marker again. + */ + g_usleep (100); + } + } + else + { + if (g_atomic_int_add (&kill_unused_threads, -1) > 0) + { + pool = NULL; + break; + } + + DEBUG_MSG (("thread %p updating to new limits.", + g_thread_self ())); + + local_max_unused_threads = g_atomic_int_get (&max_unused_threads); + local_max_idle_time = g_atomic_int_get (&max_idle_time); + last_wakeup_thread_serial = local_wakeup_thread_serial; + + have_relayed_thread_marker = FALSE; + } + } + } + while (pool == wakeup_thread_marker); + + g_atomic_int_add (&unused_threads, -1); + + return pool; +} + +static gpointer +g_thread_pool_wait_for_new_task (GRealThreadPool *pool) +{ + gpointer task = NULL; + + if (pool->running || (!pool->immediate && + g_async_queue_length_unlocked (pool->queue) > 0)) + { + /* This thread pool is still active. */ + if (pool->num_threads > pool->max_threads && pool->max_threads != -1) + { + /* This is a superfluous thread, so it goes to the global pool. */ + DEBUG_MSG (("superfluous thread %p in pool %p.", + g_thread_self (), pool)); + } + else if (pool->pool.exclusive) + { + /* Exclusive threads stay attached to the pool. */ + task = g_async_queue_pop_unlocked (pool->queue); + + DEBUG_MSG (("thread %p in exclusive pool %p waits for task " + "(%d running, %d unprocessed).", + g_thread_self (), pool, pool->num_threads, + g_async_queue_length_unlocked (pool->queue))); + } + else + { + /* A thread will wait for new tasks for at most 1/2 + * second before going to the global pool. + */ + DEBUG_MSG (("thread %p in pool %p waits for up to a 1/2 second for task " + "(%d running, %d unprocessed).", + g_thread_self (), pool, pool->num_threads, + g_async_queue_length_unlocked (pool->queue))); + + task = g_async_queue_timeout_pop_unlocked (pool->queue, + G_USEC_PER_SEC / 2); + } + } + else + { + /* This thread pool is inactive, it will no longer process tasks. */ + DEBUG_MSG (("pool %p not active, thread %p will go to global pool " + "(running: %s, immediate: %s, len: %d).", + pool, g_thread_self (), + pool->running ? "true" : "false", + pool->immediate ? "true" : "false", + g_async_queue_length_unlocked (pool->queue))); + } + + return task; +} + + +static gpointer g_thread_pool_thread_proxy (gpointer data) { - GRealThreadPool *pool = data; - gboolean watcher = FALSE; + GRealThreadPool *pool; + + pool = data; + + DEBUG_MSG (("thread %p started for pool %p.", g_thread_self (), pool)); g_async_queue_lock (pool->queue); + while (TRUE) { - gpointer task; - gboolean goto_global_pool = !pool->pool.exclusive; - gint len = g_async_queue_length_unlocked (pool->queue); - - if (g_thread_should_run (pool, len)) - { - if (watcher) - { - /* This thread is actually not needed here, but it waits - * for some time anyway. If during that time a new - * request arrives, this saves process - * swicthes. Otherwise the thread will go to the global - * pool afterwards */ - GTimeVal end_time; - g_get_current_time (&end_time); - end_time.tv_usec += G_USEC_PER_SEC / 2; /* Halv a second */ - if (end_time.tv_usec >= G_USEC_PER_SEC) - { - end_time.tv_usec -= G_USEC_PER_SEC; - end_time.tv_sec += 1; - } - - task = g_async_queue_timed_pop_unlocked (pool->queue, &end_time); - } - else - { - task = g_async_queue_pop_unlocked (pool->queue); - } - - if (task) - { - watcher = FALSE; - if (pool->num_threads > pool->max_threads && - pool->max_threads != -1) - /* We are in fact a superfluous threads, so we go to - * the global pool and just hand the data further to - * the next one waiting in the queue */ - { - g_async_queue_push_unlocked (pool->queue, task); - goto_global_pool = TRUE; - } - else if (pool->running || !pool->immediate) - { - g_async_queue_unlock (pool->queue); - pool->pool.func (task, pool->pool.user_data); - g_async_queue_lock (pool->queue); - } - } - len = g_async_queue_length_unlocked (pool->queue); - } - - if (!g_thread_should_run (pool, len)) - { - g_cond_broadcast (inform_cond); - goto_global_pool = TRUE; - } - else if (len > 0) - { - /* At this pool there are no threads waiting, but tasks are. */ - goto_global_pool = FALSE; - } - else if (len == 0 && !watcher && !pool->pool.exclusive) - { - /* Here neither threads nor tasks are queued and we didn't - * just return from a timed wait. We now wait for a limited - * time at this pool for new tasks to avoid costly context - * switches. */ - goto_global_pool = FALSE; - watcher = TRUE; - } - - - if (goto_global_pool) - { - pool->num_threads--; - - if (!pool->running && !pool->waiting) - { - if (pool->num_threads == 0) - { - g_async_queue_unlock (pool->queue); - g_thread_pool_free_internal (pool); - } - else if (len == - pool->num_threads) - { - g_thread_pool_wakeup_and_stop_all (pool); - g_async_queue_unlock (pool->queue); - } - } - else - g_async_queue_unlock (pool->queue); - - g_async_queue_lock (unused_thread_queue); - - G_LOCK (unused_threads); - if ((unused_threads >= max_unused_threads && - max_unused_threads != -1)) - { - G_UNLOCK (unused_threads); - g_async_queue_unlock (unused_thread_queue); - /* Stop this thread */ - return NULL; - } - unused_threads++; - G_UNLOCK (unused_threads); - - pool = g_async_queue_pop_unlocked (unused_thread_queue); - - G_LOCK (unused_threads); - unused_threads--; - G_UNLOCK (unused_threads); - - g_async_queue_unlock (unused_thread_queue); - - if (pool == stop_this_thread_marker) - /* Stop this thread */ - return NULL; - - g_async_queue_lock (pool->queue); - - /* pool->num_threads++ is not done here, but in - * g_thread_pool_start_thread to make the new started thread - * known to the pool, before itself can do it. */ - } + gpointer task; + + task = g_thread_pool_wait_for_new_task (pool); + if (task) + { + if (pool->running || !pool->immediate) + { + /* A task was received and the thread pool is active, + * so execute the function. + */ + g_async_queue_unlock (pool->queue); + DEBUG_MSG (("thread %p in pool %p calling func.", + g_thread_self (), pool)); + pool->pool.func (task, pool->pool.user_data); + g_async_queue_lock (pool->queue); + } + } + else + { + /* No task was received, so this thread goes to the global pool. */ + gboolean free_pool = FALSE; + + DEBUG_MSG (("thread %p leaving pool %p for global pool.", + g_thread_self (), pool)); + pool->num_threads--; + + if (!pool->running) + { + if (!pool->waiting) + { + if (pool->num_threads == 0) + { + /* If the pool is not running and no other + * thread is waiting for this thread pool to + * finish and this is the last thread of this + * pool, free the pool. + */ + free_pool = TRUE; + } + else + { + /* If the pool is not running and no other + * thread is waiting for this thread pool to + * finish and this is not the last thread of + * this pool and there are no tasks left in the + * queue, wakeup the remaining threads. + */ + if (g_async_queue_length_unlocked (pool->queue) == + - pool->num_threads) + g_thread_pool_wakeup_and_stop_all (pool); + } + } + else if (pool->immediate || + g_async_queue_length_unlocked (pool->queue) <= 0) + { + /* If the pool is not running and another thread is + * waiting for this thread pool to finish and there + * are either no tasks left or the pool shall stop + * immediately, inform the waiting thread of a change + * of the thread pool state. + */ + g_cond_broadcast (&pool->cond); + } + } + + g_async_queue_unlock (pool->queue); + + if (free_pool) + g_thread_pool_free_internal (pool); + + if ((pool = g_thread_pool_wait_for_new_pool ()) == NULL) + break; + + g_async_queue_lock (pool->queue); + + DEBUG_MSG (("thread %p entering pool %p from global pool.", + g_thread_self (), pool)); + + /* pool->num_threads++ is not done here, but in + * g_thread_pool_start_thread to make the new started + * thread known to the pool before itself can do it. + */ + } } + return NULL; } -static void -g_thread_pool_start_thread (GRealThreadPool *pool, - GError **error) +static gboolean +g_thread_pool_start_thread (GRealThreadPool *pool, + GError **error) { gboolean success = FALSE; - + if (pool->num_threads >= pool->max_threads && pool->max_threads != -1) /* Enough threads are already running */ - return; + return TRUE; g_async_queue_lock (unused_thread_queue); @@ -221,31 +401,34 @@ g_thread_pool_start_thread (GRealThreadPool *pool, if (!success) { - GError *local_error = NULL; + GThread *thread; + /* No thread was found, we have to start a new one */ - g_thread_create (g_thread_pool_thread_proxy, pool, FALSE, &local_error); - - if (local_error) - { - g_propagate_error (error, local_error); - return; - } + thread = g_thread_try_new ("pool", g_thread_pool_thread_proxy, pool, error); + + if (thread == NULL) + return FALSE; + + g_thread_unref (thread); } /* See comment in g_thread_pool_thread_proxy as to why this is done - * here and not there */ + * here and not there + */ pool->num_threads++; + + return TRUE; } /** - * g_thread_pool_new: + * g_thread_pool_new: * @func: a function to execute in the threads of the new thread pool - * @user_data: user data that is handed over to @func every time it - * is called - * @max_threads: the maximal number of threads to execute concurrently in - * the new thread pool, -1 means no limit + * @user_data: user data that is handed over to @func every time it + * is called + * @max_threads: the maximal number of threads to execute concurrently + * in the new thread pool, -1 means no limit * @exclusive: should this thread pool be exclusive? - * @error: return location for error + * @error: return location for error, or %NULL * * This function creates a new thread pool. * @@ -253,31 +436,31 @@ g_thread_pool_start_thread (GRealThreadPool *pool, * created or an unused one is reused. At most @max_threads threads * are running concurrently for this thread pool. @max_threads = -1 * allows unlimited threads to be created for this thread pool. The - * newly created or reused thread now executes the function @func with - * the two arguments. The first one is the parameter to + * newly created or reused thread now executes the function @func + * with the two arguments. The first one is the parameter to * g_thread_pool_push() and the second one is @user_data. * - * The parameter @exclusive determines, whether the thread pool owns - * all threads exclusive or whether the threads are shared - * globally. If @exclusive is @TRUE, @max_threads threads are started - * immediately and they will run exclusively for this thread pool until - * it is destroyed by g_thread_pool_free(). If @exclusive is @FALSE, - * threads are created, when needed and shared between all - * non-exclusive thread pools. This implies that @max_threads may not - * be -1 for exclusive thread pools. - * - * @error can be NULL to ignore errors, or non-NULL to report - * errors. An error can only occur, when @exclusive is set to @TRUE and - * not all @max_threads threads could be created. - * - * Return value: the new #GThreadPool - **/ -GThreadPool* -g_thread_pool_new (GFunc func, - gpointer user_data, - gint max_threads, - gboolean exclusive, - GError **error) + * The parameter @exclusive determines whether the thread pool owns + * all threads exclusive or shares them with other thread pools. + * If @exclusive is %TRUE, @max_threads threads are started + * immediately and they will run exclusively for this thread pool + * until it is destroyed by g_thread_pool_free(). If @exclusive is + * %FALSE, threads are created when needed and shared between all + * non-exclusive thread pools. This implies that @max_threads may + * not be -1 for exclusive thread pools. + * + * @error can be %NULL to ignore errors, or non-%NULL to report + * errors. An error can only occur when @exclusive is set to %TRUE + * and not all @max_threads threads could be created. + * + * Returns: the new #GThreadPool + */ +GThreadPool * +g_thread_pool_new (GFunc func, + gpointer user_data, + gint max_threads, + gboolean exclusive, + GError **error) { GRealThreadPool *retval; G_LOCK_DEFINE_STATIC (init); @@ -285,7 +468,6 @@ g_thread_pool_new (GFunc func, g_return_val_if_fail (func, NULL); g_return_val_if_fail (!exclusive || max_threads != -1, NULL); g_return_val_if_fail (max_threads >= -1, NULL); - g_return_val_if_fail (g_thread_supported (), NULL); retval = g_new (GRealThreadPool, 1); @@ -293,35 +475,34 @@ g_thread_pool_new (GFunc func, retval->pool.user_data = user_data; retval->pool.exclusive = exclusive; retval->queue = g_async_queue_new (); + g_cond_init (&retval->cond); retval->max_threads = max_threads; retval->num_threads = 0; retval->running = TRUE; + retval->immediate = FALSE; + retval->waiting = FALSE; + retval->sort_func = NULL; + retval->sort_user_data = NULL; G_LOCK (init); - - if (!inform_mutex) - { - inform_mutex = g_mutex_new (); - inform_cond = g_cond_new (); + if (!unused_thread_queue) unused_thread_queue = g_async_queue_new (); - } - G_UNLOCK (init); if (retval->pool.exclusive) { g_async_queue_lock (retval->queue); - + while (retval->num_threads < retval->max_threads) - { - GError *local_error = NULL; - g_thread_pool_start_thread (retval, &local_error); - if (local_error) - { - g_propagate_error (error, local_error); - break; - } - } + { + GError *local_error = NULL; + + if (!g_thread_pool_start_thread (retval, &local_error)) + { + g_propagate_error (error, local_error); + break; + } + } g_async_queue_unlock (retval->queue); } @@ -333,102 +514,132 @@ g_thread_pool_new (GFunc func, * g_thread_pool_push: * @pool: a #GThreadPool * @data: a new task for @pool - * @error: return location for error - * - * Inserts @data into the list of tasks to be executed by @pool. When - * the number of currently running threads is lower than the maximal - * allowed number of threads, a new thread is started (or reused) with - * the properties given to g_thread_pool_new (). Otherwise @data stays - * in the queue until a thread in this pool finishes its previous task - * and processes @data. - * - * @error can be NULL to ignore errors, or non-NULL to report - * errors. An error can only occur, when a new thread couldn't be - * created. In that case @data is simply appended to the queue of work - * to do. - **/ -void -g_thread_pool_push (GThreadPool *pool, - gpointer data, - GError **error) + * @error: return location for error, or %NULL + * + * Inserts @data into the list of tasks to be executed by @pool. + * + * When the number of currently running threads is lower than the + * maximal allowed number of threads, a new thread is started (or + * reused) with the properties given to g_thread_pool_new(). + * Otherwise, @data stays in the queue until a thread in this pool + * finishes its previous task and processes @data. + * + * @error can be %NULL to ignore errors, or non-%NULL to report + * errors. An error can only occur when a new thread couldn't be + * created. In that case @data is simply appended to the queue of + * work to do. + * + * Before version 2.32, this function did not return a success status. + * + * Returns: %TRUE on success, %FALSE if an error occurred + */ +gboolean +g_thread_pool_push (GThreadPool *pool, + gpointer data, + GError **error) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; + gboolean result; - g_return_if_fail (real); + real = (GRealThreadPool*) pool; + + g_return_val_if_fail (real, FALSE); + g_return_val_if_fail (real->running, FALSE); + + result = TRUE; g_async_queue_lock (real->queue); - - if (!real->running) - { - g_async_queue_unlock (real->queue); - g_return_if_fail (real->running); - } if (g_async_queue_length_unlocked (real->queue) >= 0) - /* No thread is waiting in the queue */ - g_thread_pool_start_thread (real, error); + { + /* No thread is waiting in the queue */ + GError *local_error = NULL; + + if (!g_thread_pool_start_thread (real, &local_error)) + { + g_propagate_error (error, local_error); + result = FALSE; + } + } - g_async_queue_push_unlocked (real->queue, data); + g_thread_pool_queue_push_unlocked (real, data); g_async_queue_unlock (real->queue); + + return result; } /** * g_thread_pool_set_max_threads: * @pool: a #GThreadPool - * @max_threads: a new maximal number of threads for @pool - * @error: return location for error - * - * Sets the maximal allowed number of threads for @pool. A value of -1 - * means, that the maximal number of threads is unlimited. - * - * Setting @max_threads to 0 means stopping all work for @pool. It is - * effectively frozen until @max_threads is set to a non-zero value - * again. - * + * @max_threads: a new maximal number of threads for @pool, + * or -1 for unlimited + * @error: return location for error, or %NULL + * + * Sets the maximal allowed number of threads for @pool. + * A value of -1 means that the maximal number of threads + * is unlimited. If @pool is an exclusive thread pool, setting + * the maximal number of threads to -1 is not allowed. + * + * Setting @max_threads to 0 means stopping all work for @pool. + * It is effectively frozen until @max_threads is set to a non-zero + * value again. + * * A thread is never terminated while calling @func, as supplied by - * g_thread_pool_new (). Instead the maximal number of threads only - * has effect for the allocation of new threads in g_thread_pool_push - * (). A new thread is allocated, whenever the number of currently + * g_thread_pool_new(). Instead the maximal number of threads only + * has effect for the allocation of new threads in g_thread_pool_push(). + * A new thread is allocated, whenever the number of currently * running threads in @pool is smaller than the maximal number. * - * @error can be NULL to ignore errors, or non-NULL to report - * errors. An error can only occur, when a new thread couldn't be - * created. - **/ -void -g_thread_pool_set_max_threads (GThreadPool *pool, - gint max_threads, - GError **error) + * @error can be %NULL to ignore errors, or non-%NULL to report + * errors. An error can only occur when a new thread couldn't be + * created. + * + * Before version 2.32, this function did not return a success status. + * + * Returns: %TRUE on success, %FALSE if an error occurred + */ +gboolean +g_thread_pool_set_max_threads (GThreadPool *pool, + gint max_threads, + GError **error) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; gint to_start; + gboolean result; - g_return_if_fail (real); - g_return_if_fail (real->running); - g_return_if_fail (!real->pool.exclusive || max_threads != -1); - g_return_if_fail (max_threads >= -1); + real = (GRealThreadPool*) pool; + + g_return_val_if_fail (real, FALSE); + g_return_val_if_fail (real->running, FALSE); + g_return_val_if_fail (!real->pool.exclusive || max_threads != -1, FALSE); + g_return_val_if_fail (max_threads >= -1, FALSE); + + result = TRUE; g_async_queue_lock (real->queue); real->max_threads = max_threads; - + if (pool->exclusive) to_start = real->max_threads - real->num_threads; else to_start = g_async_queue_length_unlocked (real->queue); - + for ( ; to_start > 0; to_start--) { GError *local_error = NULL; - g_thread_pool_start_thread (real, &local_error); - if (local_error) - { - g_propagate_error (error, local_error); - break; - } + + if (!g_thread_pool_start_thread (real, &local_error)) + { + g_propagate_error (error, local_error); + result = FALSE; + break; + } } - + g_async_queue_unlock (real->queue); + + return result; } /** @@ -437,21 +648,21 @@ g_thread_pool_set_max_threads (GThreadPool *pool, * * Returns the maximal number of threads for @pool. * - * Return value: the maximal number of threads - **/ + * Returns: the maximal number of threads + */ gint -g_thread_pool_get_max_threads (GThreadPool *pool) +g_thread_pool_get_max_threads (GThreadPool *pool) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; gint retval; + real = (GRealThreadPool*) pool; + g_return_val_if_fail (real, 0); g_return_val_if_fail (real->running, 0); g_async_queue_lock (real->queue); - retval = real->max_threads; - g_async_queue_unlock (real->queue); return retval; @@ -463,21 +674,21 @@ g_thread_pool_get_max_threads (GThreadPool *pool) * * Returns the number of threads currently running in @pool. * - * Return value: the number of threads currently running - **/ + * Returns: the number of threads currently running + */ guint -g_thread_pool_get_num_threads (GThreadPool *pool) +g_thread_pool_get_num_threads (GThreadPool *pool) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; guint retval; + real = (GRealThreadPool*) pool; + g_return_val_if_fail (real, 0); g_return_val_if_fail (real->running, 0); g_async_queue_lock (real->queue); - retval = real->num_threads; - g_async_queue_unlock (real->queue); return retval; @@ -489,14 +700,16 @@ g_thread_pool_get_num_threads (GThreadPool *pool) * * Returns the number of tasks still unprocessed in @pool. * - * Return value: the number of unprocessed tasks - **/ + * Returns: the number of unprocessed tasks + */ guint -g_thread_pool_unprocessed (GThreadPool *pool) +g_thread_pool_unprocessed (GThreadPool *pool) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; gint unprocessed; + real = (GRealThreadPool*) pool; + g_return_val_if_fail (real, 0); g_return_val_if_fail (real->running, 0); @@ -509,69 +722,73 @@ g_thread_pool_unprocessed (GThreadPool *pool) * g_thread_pool_free: * @pool: a #GThreadPool * @immediate: should @pool shut down immediately? - * @wait: should the function wait for all tasks to be finished? + * @wait_: should the function wait for all tasks to be finished? * * Frees all resources allocated for @pool. * - * If @immediate is #TRUE, no new task is processed for - * @pool. Otherwise @pool is not freed before the last task is - * processed. Note however, that no thread of this pool is - * interrupted, while processing a task. Instead at least all still - * running threads can finish their tasks before the @pool is freed. + * If @immediate is %TRUE, no new task is processed for @pool. + * Otherwise @pool is not freed before the last task is processed. + * Note however, that no thread of this pool is interrupted while + * processing a task. Instead at least all still running threads + * can finish their tasks before the @pool is freed. * - * If @wait is #TRUE, the functions does not return before all tasks - * to be processed (dependent on @immediate, whether all or only the - * currently running) are ready. Otherwise the function returns immediately. + * If @wait_ is %TRUE, the functions does not return before all + * tasks to be processed (dependent on @immediate, whether all + * or only the currently running) are ready. + * Otherwise the function returns immediately. * - * After calling this function @pool must not be used anymore. - **/ + * After calling this function @pool must not be used anymore. + */ void -g_thread_pool_free (GThreadPool *pool, - gboolean immediate, - gboolean wait) +g_thread_pool_free (GThreadPool *pool, + gboolean immediate, + gboolean wait_) { - GRealThreadPool *real = (GRealThreadPool*) pool; + GRealThreadPool *real; + + real = (GRealThreadPool*) pool; g_return_if_fail (real); g_return_if_fail (real->running); - /* It there's no thread allowed here, there is not much sense in - * not stopping this pool immediately, when it's not empty */ - g_return_if_fail (immediate || real->max_threads != 0 || - g_async_queue_length (real->queue) == 0); + + /* If there's no thread allowed here, there is not much sense in + * not stopping this pool immediately, when it's not empty + */ + g_return_if_fail (immediate || + real->max_threads != 0 || + g_async_queue_length (real->queue) == 0); g_async_queue_lock (real->queue); real->running = FALSE; real->immediate = immediate; - real->waiting = wait; + real->waiting = wait_; - if (wait) + if (wait_) { - g_mutex_lock (inform_mutex); - while (g_async_queue_length_unlocked (real->queue) != -real->num_threads) - { - g_async_queue_unlock (real->queue); - g_cond_wait (inform_cond, inform_mutex); - g_async_queue_lock (real->queue); - } - g_mutex_unlock (inform_mutex); + while (g_async_queue_length_unlocked (real->queue) != -real->num_threads && + !(immediate && real->num_threads == 0)) + g_cond_wait (&real->cond, _g_async_queue_get_mutex (real->queue)); } - if (g_async_queue_length_unlocked (real->queue) == -real->num_threads) + if (immediate || g_async_queue_length_unlocked (real->queue) == -real->num_threads) { /* No thread is currently doing something (and nothing is left - * to process in the queue) */ - if (real->num_threads == 0) /* No threads left, we clean up */ - { - g_async_queue_unlock (real->queue); - g_thread_pool_free_internal (real); - return; - } + * to process in the queue) + */ + if (real->num_threads == 0) + { + /* No threads left, we clean up */ + g_async_queue_unlock (real->queue); + g_thread_pool_free_internal (real); + return; + } g_thread_pool_wakeup_and_stop_all (real); } - - real->waiting = FALSE; /* The last thread should cleanup the pool */ + + /* The last thread should cleanup the pool */ + real->waiting = FALSE; g_async_queue_unlock (real->queue); } @@ -579,26 +796,32 @@ static void g_thread_pool_free_internal (GRealThreadPool* pool) { g_return_if_fail (pool); - g_return_if_fail (!pool->running); + g_return_if_fail (pool->running == FALSE); g_return_if_fail (pool->num_threads == 0); g_async_queue_unref (pool->queue); + g_cond_clear (&pool->cond); g_free (pool); } static void -g_thread_pool_wakeup_and_stop_all (GRealThreadPool* pool) +g_thread_pool_wakeup_and_stop_all (GRealThreadPool *pool) { guint i; - + g_return_if_fail (pool); - g_return_if_fail (!pool->running); + g_return_if_fail (pool->running == FALSE); g_return_if_fail (pool->num_threads != 0); - g_return_if_fail (g_async_queue_length_unlocked (pool->queue) == - -pool->num_threads); - pool->immediate = TRUE; + pool->immediate = TRUE; + + /* + * So here we're sending bogus data to the pool threads, which + * should cause them each to wake up, and check the above + * pool->immediate condition. However we don't want that + * data to be sorted (since it'll crash the sorter). + */ for (i = 0; i < pool->num_threads; i++) g_async_queue_push_unlocked (pool->queue, GUINT_TO_POINTER (1)); } @@ -607,80 +830,192 @@ g_thread_pool_wakeup_and_stop_all (GRealThreadPool* pool) * g_thread_pool_set_max_unused_threads: * @max_threads: maximal number of unused threads * - * Sets the maximal number of unused threads to @max_threads. If - * @max_threads is -1, no limit is imposed on the number of unused - * threads. - **/ + * Sets the maximal number of unused threads to @max_threads. + * If @max_threads is -1, no limit is imposed on the number + * of unused threads. + * + * The default value is 2. + */ void g_thread_pool_set_max_unused_threads (gint max_threads) { - g_return_if_fail (max_threads >= -1); + g_return_if_fail (max_threads >= -1); - G_LOCK (unused_threads); - - max_unused_threads = max_threads; + g_atomic_int_set (&max_unused_threads, max_threads); - if (max_unused_threads < unused_threads && max_unused_threads != -1) + if (max_threads != -1) { - guint i; - - g_async_queue_lock (unused_thread_queue); - for (i = unused_threads - max_unused_threads; i > 0; i--) - g_async_queue_push_unlocked (unused_thread_queue, - stop_this_thread_marker); - g_async_queue_unlock (unused_thread_queue); + max_threads -= g_atomic_int_get (&unused_threads); + if (max_threads < 0) + { + g_atomic_int_set (&kill_unused_threads, -max_threads); + g_atomic_int_inc (&wakeup_thread_serial); + + g_async_queue_lock (unused_thread_queue); + + do + { + g_async_queue_push_unlocked (unused_thread_queue, + wakeup_thread_marker); + } + while (++max_threads); + + g_async_queue_unlock (unused_thread_queue); + } } - - G_UNLOCK (unused_threads); } /** * g_thread_pool_get_max_unused_threads: - * + * * Returns the maximal allowed number of unused threads. * - * Return value: the maximal number of unused threads - **/ + * Returns: the maximal number of unused threads + */ gint g_thread_pool_get_max_unused_threads (void) { - gint retval; - - G_LOCK (unused_threads); - retval = max_unused_threads; - G_UNLOCK (unused_threads); - - return retval; + return g_atomic_int_get (&max_unused_threads); } /** * g_thread_pool_get_num_unused_threads: - * + * * Returns the number of currently unused threads. * - * Return value: the number of currently unused threads - **/ -guint g_thread_pool_get_num_unused_threads (void) + * Returns: the number of currently unused threads + */ +guint +g_thread_pool_get_num_unused_threads (void) { - guint retval; - - G_LOCK (unused_threads); - retval = unused_threads; - G_UNLOCK (unused_threads); - - return retval; + return g_atomic_int_get (&unused_threads); } /** * g_thread_pool_stop_unused_threads: - * + * * Stops all currently unused threads. This does not change the * maximal number of unused threads. This function can be used to * regularly stop all unused threads e.g. from g_timeout_add(). - **/ -void g_thread_pool_stop_unused_threads (void) -{ - guint oldval = g_thread_pool_get_max_unused_threads (); + */ +void +g_thread_pool_stop_unused_threads (void) +{ + guint oldval; + + oldval = g_thread_pool_get_max_unused_threads (); + g_thread_pool_set_max_unused_threads (0); g_thread_pool_set_max_unused_threads (oldval); } + +/** + * g_thread_pool_set_sort_function: + * @pool: a #GThreadPool + * @func: the #GCompareDataFunc used to sort the list of tasks. + * This function is passed two tasks. It should return + * 0 if the order in which they are handled does not matter, + * a negative value if the first task should be processed before + * the second or a positive value if the second task should be + * processed first. + * @user_data: user data passed to @func + * + * Sets the function used to sort the list of tasks. This allows the + * tasks to be processed by a priority determined by @func, and not + * just in the order in which they were added to the pool. + * + * Note, if the maximum number of threads is more than 1, the order + * that threads are executed cannot be guaranteed 100%. Threads are + * scheduled by the operating system and are executed at random. It + * cannot be assumed that threads are executed in the order they are + * created. + * + * Since: 2.10 + */ +void +g_thread_pool_set_sort_function (GThreadPool *pool, + GCompareDataFunc func, + gpointer user_data) +{ + GRealThreadPool *real; + + real = (GRealThreadPool*) pool; + + g_return_if_fail (real); + g_return_if_fail (real->running); + + g_async_queue_lock (real->queue); + + real->sort_func = func; + real->sort_user_data = user_data; + + if (func) + g_async_queue_sort_unlocked (real->queue, + real->sort_func, + real->sort_user_data); + + g_async_queue_unlock (real->queue); +} + +/** + * g_thread_pool_set_max_idle_time: + * @interval: the maximum @interval (in milliseconds) + * a thread can be idle + * + * This function will set the maximum @interval that a thread + * waiting in the pool for new tasks can be idle for before + * being stopped. This function is similar to calling + * g_thread_pool_stop_unused_threads() on a regular timeout, + * except this is done on a per thread basis. + * + * By setting @interval to 0, idle threads will not be stopped. + * + * The default value is 15000 (15 seconds). + * + * Since: 2.10 + */ +void +g_thread_pool_set_max_idle_time (guint interval) +{ + guint i; + + g_atomic_int_set (&max_idle_time, interval); + + i = g_atomic_int_get (&unused_threads); + if (i > 0) + { + g_atomic_int_inc (&wakeup_thread_serial); + g_async_queue_lock (unused_thread_queue); + + do + { + g_async_queue_push_unlocked (unused_thread_queue, + wakeup_thread_marker); + } + while (--i); + + g_async_queue_unlock (unused_thread_queue); + } +} + +/** + * g_thread_pool_get_max_idle_time: + * + * This function will return the maximum @interval that a + * thread will wait in the thread pool for new tasks before + * being stopped. + * + * If this function returns 0, threads waiting in the thread + * pool for new work are not stopped. + * + * Returns: the maximum @interval (milliseconds) to wait + * for new tasks in the thread pool before stopping the + * thread + * + * Since: 2.10 + */ +guint +g_thread_pool_get_max_idle_time (void) +{ + return g_atomic_int_get (&max_idle_time); +}