X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fjobs.c;h=83ca2ed4e11a23321837f96c6bd47efc36b86278;hb=d9de3cd38b17ad16fb6ad6f74e83f4700c5f2b49;hp=9c81700a54f84535a3b6900ca54488603c353ae3;hpb=cab05ba72abeb335b456b0820e053c94b91986e7;p=src%2Fapp-framework-binder.git diff --git a/src/jobs.c b/src/jobs.c index 9c81700a..83ca2ed4 100644 --- a/src/jobs.c +++ b/src/jobs.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2016, 2017, 2018 "IoT.bzh" + * Copyright (C) 2016-2019 "IoT.bzh" * Author José Bollo * * Licensed under the Apache License, Version 2.0 (the "License"); @@ -17,12 +17,6 @@ #define _GNU_SOURCE -#if defined(NO_JOBS_WATCHDOG) -# define HAS_WATCHDOG 0 -#else -# define HAS_WATCHDOG 1 -#endif - #include #include #include @@ -36,26 +30,18 @@ #include #include -#include "fdev.h" -#if HAS_WATCHDOG -#include -#endif #include "jobs.h" -#include "fdev-epoll.h" +#include "evmgr.h" #include "sig-monitor.h" #include "verbose.h" - -#if 0 -#define _alert_ "do you really want to remove signal monitoring?" -#define sig_monitor_init_timeouts() ((void)0) -#define sig_monitor_clean_timeouts() ((void)0) -#define sig_monitor(to,cb,arg) (cb(0,arg)) -#endif +#include "systemd.h" #define EVENT_TIMEOUT_TOP ((uint64_t)-1) #define EVENT_TIMEOUT_CHILD ((uint64_t)10000) +struct thread; + /** Internal shortcut for callback */ typedef void (*job_cb_t)(int, void*); @@ -71,33 +57,21 @@ struct job unsigned dropped: 1; /**< is removed ? */ }; -/** Description of handled event loops */ -struct evloop -{ - unsigned state; /**< encoded state */ - int efd; /**< event notification */ - struct sd_event *sdev; /**< the systemd event loop */ - pthread_cond_t cond; /**< condition */ - struct fdev *fdev; /**< handling of events */ -}; - -#define EVLOOP_STATE_WAIT 1U -#define EVLOOP_STATE_RUN 2U -#define EVLOOP_STATE_LOCK 4U - /** Description of threads */ struct thread { struct thread *next; /**< next thread of the list */ struct thread *upper; /**< upper same thread */ + struct thread *nholder;/**< next holder for evloop */ + pthread_cond_t *cwhold;/**< condition wait for holding */ struct job *job; /**< currently processed job */ pthread_t tid; /**< the thread id */ - unsigned stop: 1; /**< stop requested */ - unsigned waits: 1; /**< is waiting? */ + volatile unsigned stop: 1; /**< stop requested */ + volatile unsigned waits: 1; /**< is waiting? */ }; /** - * Description of synchonous callback + * Description of synchronous callback */ struct sync { @@ -124,16 +98,13 @@ static int remains = 0; /** allowed count of waiting jobs */ /* list of threads */ static struct thread *threads; static _Thread_local struct thread *current_thread; -static _Thread_local struct evloop *current_evloop; /* queue of pending jobs */ static struct job *first_job; static struct job *free_jobs; /* event loop */ -static struct evloop evloop[1]; -static struct fdev_epoll *fdevepoll; -static int waitevt; +static struct evmgr *evmgr; /** * Create a new job with the given parameters @@ -161,7 +132,8 @@ static struct job *job_create( job = malloc(sizeof *job); pthread_mutex_lock(&mutex); if (!job) { - errno = -ENOMEM; + ERROR("out of memory"); + errno = ENOMEM; goto end; } } @@ -202,6 +174,7 @@ static void job_add(struct job *job) /* queue the jobs */ *pjob = job; + remains--; } /** @@ -213,6 +186,8 @@ static inline struct job *job_get() struct job *job = first_job; while (job && job->blocked) job = job->next; + if (job) + remains++; return job; } @@ -268,120 +243,130 @@ static void job_cancel(int signum, void *arg) } /** - * Gets a fdev_epoll item. - * @return a fdev_epoll or NULL in case of error + * wakeup the event loop if needed by sending + * an event. */ -static struct fdev_epoll *get_fdevepoll() +static void evloop_wakeup() { - struct fdev_epoll *result; - - result = fdevepoll; - if (!result) - result = fdevepoll = fdev_epoll_create(); - - return result; + if (evmgr) + evmgr_wakeup(evmgr); } /** - * Monitored normal callback for events. - * This function is called by the monitor - * to run the event loop when the safe environment - * is set. - * @param signum 0 on normal flow or the number - * of the signal that interrupted the normal - * flow - * @param arg the events to run + * Release the currently held event loop */ -static void evloop_run(int signum, void *arg) +static void evloop_release() { - int rc; - struct sd_event *se; - struct evloop *el = arg; - - if (!signum) { - current_evloop = el; - __atomic_store_n(&el->state, EVLOOP_STATE_LOCK|EVLOOP_STATE_RUN|EVLOOP_STATE_WAIT, __ATOMIC_RELAXED); - se = el->sdev; - rc = sd_event_prepare(se); - if (rc < 0) { - errno = -rc; - ERROR("sd_event_prepare returned an error (state: %d): %m", sd_event_get_state(se)); - } else { - if (rc == 0) { - rc = sd_event_wait(se, (uint64_t)(int64_t)-1); - if (rc < 0) { - errno = -rc; - ERROR("sd_event_wait returned an error (state: %d): %m", sd_event_get_state(se)); - } - } - __atomic_and_fetch(&el->state, ~(EVLOOP_STATE_WAIT), __ATOMIC_RELAXED); - - if (rc > 0) { - rc = sd_event_dispatch(se); - if (rc < 0) { - errno = -rc; - ERROR("sd_event_dispatch returned an error (state: %d): %m", sd_event_get_state(se)); - } - } + struct thread *nh, *ct = current_thread; + + if (ct && evmgr && evmgr_release_if(evmgr, ct)) { + nh = ct->nholder; + ct->nholder = 0; + if (nh) { + evmgr_try_hold(evmgr, nh); + pthread_cond_signal(nh->cwhold); } } - __atomic_and_fetch(&el->state, ~(EVLOOP_STATE_WAIT|EVLOOP_STATE_RUN), __ATOMIC_RELAXED); } +/** + * get the eventloop for the current thread + */ +static int evloop_get() +{ + return evmgr && evmgr_try_hold(evmgr, current_thread); +} /** - * Monitored normal loop for waiting events. - * @param signum 0 on normal flow or the number - * of the signal that interrupted the normal - * flow - * @param arg the events to run + * acquire the eventloop for the current thread */ -static void monitored_wait_and_dispatch(int signum, void *arg) +static void evloop_acquire() { - struct fdev_epoll *fdev_epoll = arg; - if (!signum) { - fdev_epoll_wait_and_dispatch(fdev_epoll, -1); + struct thread *pwait, *ct; + pthread_cond_t cond; + + /* try to get the evloop */ + if (!evloop_get()) { + /* failed, init waiting state */ + ct = current_thread; + ct->nholder = NULL; + ct->cwhold = &cond; + pthread_cond_init(&cond, NULL); + + /* queue current thread in holder list */ + pwait = evmgr_holder(evmgr); + while (pwait->nholder) + pwait = pwait->nholder; + pwait->nholder = ct; + + /* wake up the evloop */ + evloop_wakeup(); + + /* wait to acquire the evloop */ + pthread_cond_wait(&cond, &mutex); + pthread_cond_destroy(&cond); } } /** - * Main processing loop of threads processing jobs. - * The loop must be called with the mutex locked - * and it returns with the mutex locked. - * @param me the description of the thread to use - * TODO: how are timeout handled when reentering? + * Enter the thread + * @param me the description of the thread to enter */ -static void thread_run(volatile struct thread *me) +static void thread_enter(volatile struct thread *me) { - struct thread **prv; - struct job *job; - + evloop_release(); /* initialize description of itself and link it in the list */ me->tid = pthread_self(); me->stop = 0; me->waits = 0; + me->nholder = 0; me->upper = current_thread; - if (!current_thread) { - started++; - sig_monitor_init_timeouts(); - } me->next = threads; threads = (struct thread*)me; current_thread = (struct thread*)me; +} + +/** + * leave the thread + * @param me the description of the thread to leave + */ +static void thread_leave() +{ + struct thread **prv, *me; + + /* unlink the current thread and cleanup */ + me = current_thread; + prv = &threads; + while (*prv != me) + prv = &(*prv)->next; + *prv = me->next; + + current_thread = me->upper; +} + +/** + * Main processing loop of internal threads with processing jobs. + * The loop must be called with the mutex locked + * and it returns with the mutex locked. + * @param me the description of the thread to use + * TODO: how are timeout handled when reentering? + */ +static void thread_run_internal(volatile struct thread *me) +{ + struct job *job; + + /* enter thread */ + thread_enter(me); /* loop until stopped */ while (!me->stop) { - /* release the event loop */ - if (current_evloop) { - __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED); - current_evloop = NULL; - } + /* release the current event loop */ + evloop_release(); /* get a job */ - job = job_get(first_job); + job = job_get(); if (job) { /* prepare running the job */ - remains++; /* increases count of job that can wait */ job->blocked = 1; /* mark job as blocked */ me->job = job; /* record the job (only for terminate) */ @@ -392,8 +377,19 @@ static void thread_run(volatile struct thread *me) /* release the run job */ job_release(job); - } else if (waitevt) { - /* no job and not events */ + /* no job, check event loop wait */ + } else if (evloop_get()) { + if (!evmgr_can_run(evmgr)) { + /* busy ? */ + CRITICAL("Can't enter dispatch while in dispatch!"); + abort(); + } + /* run the events */ + pthread_mutex_unlock(&mutex); + sig_monitor(0, (void(*)(int,void*))evmgr_job_run, evmgr); + pthread_mutex_lock(&mutex); + } else { + /* no job and no event loop */ running--; if (!running) ERROR("Entering job deep sleep! Check your bindings."); @@ -401,47 +397,57 @@ static void thread_run(volatile struct thread *me) pthread_cond_wait(&cond, &mutex); me->waits = 0; running++; - } else { - /* wait for events */ - waitevt = 1; - pthread_mutex_unlock(&mutex); - sig_monitor(0, monitored_wait_and_dispatch, get_fdevepoll()); - pthread_mutex_lock(&mutex); - waitevt = 0; } } + /* cleanup */ + evloop_release(); + thread_leave(); +} - /* release the event loop */ - if (current_evloop) { - __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED); - current_evloop = NULL; - } +/** + * Main processing loop of external threads. + * The loop must be called with the mutex locked + * and it returns with the mutex locked. + * @param me the description of the thread to use + */ +static void thread_run_external(volatile struct thread *me) +{ + /* enter thread */ + thread_enter(me); - /* unlink the current thread and cleanup */ - prv = &threads; - while (*prv != me) - prv = &(*prv)->next; - *prv = me->next; - current_thread = me->upper; - if (!current_thread) { - sig_monitor_clean_timeouts(); - started--; - } + /* loop until stopped */ + me->waits = 1; + while (!me->stop) + pthread_cond_wait(&cond, &mutex); + me->waits = 0; + thread_leave(); } /** - * Entry point for created threads. - * @param data not used - * @return NULL + * Root for created threads. */ -static void *thread_main(void *data) +static void thread_main() { struct thread me; - pthread_mutex_lock(&mutex); running++; - thread_run(&me); + started++; + sig_monitor_init_timeouts(); + thread_run_internal(&me); + sig_monitor_clean_timeouts(); + started--; running--; +} + +/** + * Entry point for created threads. + * @param data not used + * @return NULL + */ +static void *thread_starter(void *data) +{ + pthread_mutex_lock(&mutex); + thread_main(); pthread_mutex_unlock(&mutex); return NULL; } @@ -455,7 +461,7 @@ static int start_one_thread() pthread_t tid; int rc; - rc = pthread_create(&tid, NULL, thread_main, NULL); + rc = pthread_create(&tid, NULL, thread_starter, NULL); if (rc != 0) { /* errno = rc; */ WARNING("not able to start thread: %m"); @@ -487,7 +493,6 @@ int jobs_queue( void (*callback)(int, void*), void *arg) { - const char *info; struct job *job; int rc; @@ -495,16 +500,13 @@ int jobs_queue( /* allocates the job */ job = job_create(group, timeout, callback, arg); - if (!job) { - errno = ENOMEM; - info = "out of memory"; + if (!job) goto error; - } /* check availability */ - if (remains == 0) { + if (remains <= 0) { + ERROR("can't process job with threads: too many jobs"); errno = EBUSY; - info = "too many jobs"; goto error2; } @@ -513,13 +515,12 @@ int jobs_queue( /* all threads are busy and a new can be started */ rc = start_one_thread(); if (rc < 0 && started == 0) { - info = "can't start first thread"; + ERROR("can't start initial thread: %m"); goto error2; } } /* queues the job */ - remains--; job_add(job); /* signal an existing job */ @@ -531,7 +532,6 @@ error2: job->next = free_jobs; free_jobs = job; error: - ERROR("can't process job with threads: %s, %m", info); pthread_mutex_unlock(&mutex); return -1; } @@ -577,8 +577,6 @@ static int do_sync( /* allocates the job */ job = job_create(group, timeout, sync_cb, sync); if (!job) { - ERROR("out of memory"); - errno = ENOMEM; pthread_mutex_unlock(&mutex); return -1; } @@ -587,7 +585,10 @@ static int do_sync( job_add(job); /* run until stopped */ - thread_run(&sync->thread); + if (current_thread) + thread_run_internal(&sync->thread); + else + thread_run_external(&sync->thread); pthread_mutex_unlock(&mutex); return 0; } @@ -604,7 +605,7 @@ static int do_sync( * of interrupted flow, the context 'closure' as given and * a 'jobloop' reference that must be used when the job is * terminated to unlock the current execution flow. - * @param arg the argument to the callback + * @param closure the argument to the callback * @return 0 on success or -1 in case of error */ int jobs_enter( @@ -640,6 +641,8 @@ int jobs_leave(struct jobloop *jobloop) t->stop = 1; if (t->waits) pthread_cond_broadcast(&cond); + else + evloop_wakeup(); } pthread_mutex_unlock(&mutex); return -!t; @@ -674,124 +677,48 @@ int jobs_call( } /** - * Internal callback for evloop management. - * The effect of this function is hidden: it exits - * the waiting poll if any. Then it wakes up a thread - * awaiting the evloop using signal. - */ -static int on_evloop_efd(sd_event_source *s, int fd, uint32_t revents, void *userdata) -{ - uint64_t x; - struct evloop *evloop = userdata; - read(evloop->efd, &x, sizeof x); - pthread_mutex_lock(&mutex); - pthread_cond_broadcast(&evloop->cond); - pthread_mutex_unlock(&mutex); - return 1; -} - -/* temporary hack */ -static void evloop_callback(void *arg, uint32_t event, struct fdev *fdev) -{ - sig_monitor(0, evloop_run, arg); -} - -/** - * Gets a sd_event item for the current thread. - * @return a sd_event or NULL in case of error + * Ensure that the current running thread can control the event loop. */ -static struct sd_event *get_sd_event_locked() +void jobs_acquire_event_manager() { - struct evloop *el; - uint64_t x; - int rc; - - /* creates the evloop on need */ - el = &evloop[0]; - if (!el->sdev) { - /* start the creation */ - el->state = 0; - /* creates the eventfd for waking up polls */ - el->efd = eventfd(0, EFD_CLOEXEC); - if (el->efd < 0) { - ERROR("can't make eventfd for events"); - goto error1; - } - /* create the systemd event loop */ - rc = sd_event_new(&el->sdev); - if (rc < 0) { - ERROR("can't make new event loop"); - goto error2; - } - /* put the eventfd in the event loop */ - rc = sd_event_add_io(el->sdev, NULL, el->efd, EPOLLIN, on_evloop_efd, el); - if (rc < 0) { - ERROR("can't register eventfd"); - goto error3; - } - /* handle the event loop */ - el->fdev = fdev_epoll_add(get_fdevepoll(), sd_event_get_fd(el->sdev)); - if (!el->fdev) { - ERROR("can't create fdev"); -error3: - sd_event_unref(el->sdev); -error2: - close(el->efd); -error1: - memset(el, 0, sizeof *el); - return NULL; - } - fdev_set_autoclose(el->fdev, 0); - fdev_set_events(el->fdev, EPOLLIN); - fdev_set_callback(el->fdev, evloop_callback, el); - } + struct thread lt; - /* attach the event loop to the current thread */ - if (current_evloop != el) { - if (current_evloop) - __atomic_and_fetch(¤t_evloop->state, ~EVLOOP_STATE_LOCK, __ATOMIC_RELAXED); - current_evloop = el; - __atomic_or_fetch(&el->state, EVLOOP_STATE_LOCK, __ATOMIC_RELAXED); - } - - /* wait for a modifiable event loop */ - while (__atomic_load_n(&el->state, __ATOMIC_RELAXED) & EVLOOP_STATE_WAIT) { - x = 1; - write(el->efd, &x, sizeof x); - pthread_cond_wait(&el->cond, &mutex); + /* ensure an existing thread environment */ + if (!current_thread) { + memset(<, 0, sizeof lt); + current_thread = < } - return el->sdev; -} - -/** - * Gets a sd_event item for the current thread. - * @return a sd_event or NULL in case of error - */ -struct sd_event *jobs_get_sd_event() -{ - struct sd_event *result; - + /* lock */ pthread_mutex_lock(&mutex); - result = get_sd_event_locked(); - pthread_mutex_unlock(&mutex); - return result; -} + /* creates the evloop on need */ + if (!evmgr) + evmgr_create(&evmgr); -/** - * Gets the fdev_epoll item. - * @return a fdev_epoll or NULL in case of error - */ -struct fdev_epoll *jobs_get_fdev_epoll() -{ - struct fdev_epoll *result; + /* acquire the event loop under lock */ + if (evmgr) + evloop_acquire(); - pthread_mutex_lock(&mutex); - result = get_fdevepoll(); + /* unlock */ pthread_mutex_unlock(&mutex); - return result; + /* release the faked thread environment if needed */ + if (current_thread == <) { + /* + * Releasing it is needed because there is no way to guess + * when it has to be released really. But here is where it is + * hazardous: if the caller modifies the eventloop when it + * is waiting, there is no way to make the change effective. + * A workaround to achieve that goal is for the caller to + * require the event loop a second time after having modified it. + */ + NOTICE("Requiring event manager/loop from outside of binder's callback is hazardous!"); + if (verbose_wants(Log_Level_Info)) + sig_monitor_dumpstack(); + evloop_release(); + current_thread = NULL; + } } /** @@ -805,7 +732,6 @@ struct fdev_epoll *jobs_get_fdev_epoll() int jobs_start(int allowed_count, int start_count, int waiter_count, void (*start)(int signum, void* arg), void *arg) { int rc, launched; - struct thread me; struct job *job; assert(allowed_count >= 1); @@ -823,27 +749,15 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star goto error; } - /* start */ - if (sig_monitor_init() < 0) { - ERROR("failed to initialise signal handlers"); - goto error; - } - /* records the allowed count */ allowed = allowed_count; started = 0; running = 0; remains = waiter_count; -#if HAS_WATCHDOG - /* set the watchdog */ - if (sd_watchdog_enabled(0, NULL)) - sd_event_set_watchdog(get_sd_event_locked(), 1); -#endif - - /* start at least one thread */ - launched = 0; - while ((launched + 1) < start_count) { + /* start at least one thread: the current one */ + launched = 1; + while (launched < start_count) { if (start_one_thread() != 0) { ERROR("Not all threads can be started"); goto error; @@ -853,16 +767,12 @@ int jobs_start(int allowed_count, int start_count, int waiter_count, void (*star /* queue the start job */ job = job_create(NULL, 0, start, arg); - if (!job) { - ERROR("out of memory"); - errno = ENOMEM; + if (!job) goto error; - } job_add(job); - remains--; /* run until end */ - thread_run(&me); + thread_main(); rc = 0; error: pthread_mutex_unlock(&mutex);