/* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2006-2007 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * 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. * * Author: Alexander Larsson */ #include #include "gioscheduler.h" #include "gioalias.h" /** * SECTION:gioscheduler * @short_description: I/O Scheduler * * Schedules asynchronous I/O operations. #GIOScheduler integrates into the main * event loop (#GMainLoop) and may use threads if they are available. * * I/O priority * Each I/O operation has a priority, and the scheduler uses the priorities * to determine the order in which operations are executed. They are * not used to determine system-wide I/O scheduling. * Priorities are integers, with lower numbers indicating higher priority. * It is recommended to choose priorities between %G_PRIORITY_LOW and * %G_PRIORITY_HIGH, with %G_PRIORITY_DEFAULT as a default. * **/ struct _GIOJob { GSList *active_link; GIOJobFunc job_func; GIODataFunc cancel_func; /* Runs under job map lock */ gpointer data; GDestroyNotify destroy_notify; gint io_priority; GCancellable *cancellable; guint idle_tag; }; G_LOCK_DEFINE_STATIC(active_jobs); static GSList *active_jobs = NULL; static GThreadPool *job_thread_pool = NULL; static void io_job_thread (gpointer data, gpointer user_data); static void g_io_job_free (GIOJob *job) { if (job->cancellable) g_object_unref (job->cancellable); g_free (job); } static gint g_io_job_compare (gconstpointer a, gconstpointer b, gpointer user_data) { const GIOJob *aa = a; const GIOJob *bb = b; /* Cancelled jobs are set prio == -1, so that they are executed as quickly as possible */ /* Lower value => higher priority */ if (aa->io_priority < bb->io_priority) return -1; if (aa->io_priority == bb->io_priority) return 0; return 1; } static gpointer init_scheduler (gpointer arg) { if (job_thread_pool == NULL) { /* TODO: thread_pool_new can fail */ job_thread_pool = g_thread_pool_new (io_job_thread, NULL, 10, FALSE, NULL); if (job_thread_pool != NULL) { g_thread_pool_set_sort_function (job_thread_pool, g_io_job_compare, NULL); /* Its kinda weird that this is a global setting * instead of per threadpool. However, we really * want to cache some threads, but not keep around * those threads forever. */ g_thread_pool_set_max_idle_time (15 * 1000); g_thread_pool_set_max_unused_threads (2); } } return NULL; } static void remove_active_job (GIOJob *job) { GIOJob *other_job; GSList *l; gboolean resort_jobs; G_LOCK (active_jobs); active_jobs = g_slist_delete_link (active_jobs, job->active_link); resort_jobs = FALSE; for (l = active_jobs; l != NULL; l = l->next) { other_job = l->data; if (other_job->io_priority >= 0 && g_cancellable_is_cancelled (other_job->cancellable)) { other_job->io_priority = -1; resort_jobs = TRUE; } } G_UNLOCK (active_jobs); if (resort_jobs && job_thread_pool != NULL) g_thread_pool_set_sort_function (job_thread_pool, g_io_job_compare, NULL); } static void io_job_thread (gpointer data, gpointer user_data) { GIOJob *job = data; if (job->cancellable) g_push_current_cancellable (job->cancellable); job->job_func (job, job->cancellable, job->data); if (job->cancellable) g_pop_current_cancellable (job->cancellable); if (job->destroy_notify) job->destroy_notify (job->data); remove_active_job (job); g_io_job_free (job); } static gboolean run_job_at_idle (gpointer data) { GIOJob *job = data; if (job->cancellable) g_push_current_cancellable (job->cancellable); job->job_func (job, job->cancellable, job->data); if (job->cancellable) g_pop_current_cancellable (job->cancellable); if (job->destroy_notify) job->destroy_notify (job->data); remove_active_job (job); g_io_job_free (job); return FALSE; } /** * g_schedule_io_job: * @job_func: a #GIOJobFunc. * @user_data: a #gpointer. * @notify: a #GDestroyNotify. * @io_priority: the I/O priority * of the request. * @cancellable: optional #GCancellable object, %NULL to ignore. * * Schedules the I/O Job. * **/ void g_schedule_io_job (GIOJobFunc job_func, gpointer user_data, GDestroyNotify notify, gint io_priority, GCancellable *cancellable) { static GOnce once_init = G_ONCE_INIT; GIOJob *job; g_return_if_fail (job_func != NULL); job = g_new0 (GIOJob, 1); job->job_func = job_func; job->data = user_data; job->destroy_notify = notify; job->io_priority = io_priority; if (cancellable) job->cancellable = g_object_ref (cancellable); G_LOCK (active_jobs); active_jobs = g_slist_prepend (active_jobs, job); job->active_link = active_jobs; G_UNLOCK (active_jobs); if (g_thread_supported()) { g_once (&once_init, init_scheduler, NULL); g_thread_pool_push (job_thread_pool, job, NULL); } else { /* Threads not available, instead do the i/o sync inside a * low prio idle handler */ job->idle_tag = g_idle_add_full (G_PRIORITY_DEFAULT_IDLE + 1 + io_priority / 10, run_job_at_idle, job, NULL); } } /** * g_cancel_all_io_jobs: * * Cancels all cancellable I/O Jobs. **/ void g_cancel_all_io_jobs (void) { GSList *cancellable_list, *l; G_LOCK (active_jobs); cancellable_list = NULL; for (l = active_jobs; l != NULL; l = l->next) { GIOJob *job = l->data; if (job->cancellable) cancellable_list = g_slist_prepend (cancellable_list, g_object_ref (job->cancellable)); } G_UNLOCK (active_jobs); for (l = cancellable_list; l != NULL; l = l->next) { GCancellable *c = l->data; g_cancellable_cancel (c); g_object_unref (c); } g_slist_free (cancellable_list); } typedef struct { GIODataFunc func; gpointer data; GDestroyNotify notify; GMutex *ack_lock; GCond *ack_condition; } MainLoopProxy; static gboolean mainloop_proxy_func (gpointer data) { MainLoopProxy *proxy = data; proxy->func (proxy->data); if (proxy->notify) proxy->notify (proxy->data); if (proxy->ack_lock) { g_mutex_lock (proxy->ack_lock); g_cond_signal (proxy->ack_condition); g_mutex_unlock (proxy->ack_lock); } return FALSE; } static void mainloop_proxy_free (MainLoopProxy *proxy) { if (proxy->ack_lock) { g_mutex_free (proxy->ack_lock); g_cond_free (proxy->ack_condition); } g_free (proxy); } /** * g_io_job_send_to_mainloop: * @job: a #GIOJob. * @func: a #GIODataFunc callback that will be called the main thread. * @user_data: a #gpointer. * @notify: a #GDestroyNotify. * @block: boolean flag indicating whether or not the job should block until the callback has returned. * * Sends a notification from an I/O job to the mainloop processing on the main thread. **/ void g_io_job_send_to_mainloop (GIOJob *job, GIODataFunc func, gpointer user_data, GDestroyNotify notify, gboolean block) { GSource *source; MainLoopProxy *proxy; guint id; g_return_if_fail (job != NULL); g_return_if_fail (func != NULL); if (job->idle_tag) { /* We just immediately re-enter in the case of idles (non-threads) * Anything else would just deadlock. If you can't handle this, enable threads. */ func (user_data); if (notify) notify (user_data); return; } proxy = g_new0 (MainLoopProxy, 1); proxy->func = func; proxy->data = user_data; proxy->notify = notify; if (block) { proxy->ack_lock = g_mutex_new (); proxy->ack_condition = g_cond_new (); g_mutex_lock (proxy->ack_lock); } source = g_idle_source_new (); g_source_set_priority (source, G_PRIORITY_DEFAULT); g_source_set_callback (source, mainloop_proxy_func, proxy, block ? NULL : (GDestroyNotify)mainloop_proxy_free); id = g_source_attach (source, NULL); g_source_unref (source); if (block) { g_cond_wait (proxy->ack_condition, proxy->ack_lock); g_mutex_unlock (proxy->ack_lock); /* In the blocking case we free the proxy here */ mainloop_proxy_free (proxy); } } #define __G_IO_SCHEDULER_C__ #include "gioaliasdef.c"