From db2cc8c9f2ec6f98884b1eb7738148cecdf6fd45 Mon Sep 17 00:00:00 2001 From: Volker Lendecke Date: Thu, 23 Apr 2009 17:23:13 +0200 Subject: [PATCH] Add thread pool Included if pthreads are found, can be disabled with --enable-pthreadpool=no Tim, Steven, I haven't yet seen comments from you. You have been asking for such a thing at SambaXP. Do you like this? :-) --- source3/Makefile.in | 2 +- source3/configure.in | 15 +- source3/include/pthreadpool.h | 42 +++ source3/lib/pthreadpool.c | 505 ++++++++++++++++++++++++++++++++++ 4 files changed, 562 insertions(+), 2 deletions(-) create mode 100644 source3/include/pthreadpool.h create mode 100644 source3/lib/pthreadpool.c diff --git a/source3/Makefile.in b/source3/Makefile.in index 8bf29ddfda9..eb255c20619 100644 --- a/source3/Makefile.in +++ b/source3/Makefile.in @@ -385,7 +385,7 @@ LIB_OBJ = $(LIBSAMBAUTIL_OBJ) $(UTIL_OBJ) $(CRYPTO_OBJ) \ lib/module.o lib/events.o @LIBTEVENT_OBJ0@ \ lib/ldap_escape.o @CHARSET_STATIC@ \ lib/secdesc.o lib/util_seaccess.o ../libcli/security/secace.o \ - ../libcli/security/secacl.o \ + ../libcli/security/secacl.o @PTHREADPOOL_OBJ@ \ libads/krb5_errs.o lib/system_smbd.o lib/audit.o $(LIBNDR_OBJ) \ lib/file_id.o lib/idmap_cache.o \ ../libcli/security/dom_sid.o ../libcli/security/security_descriptor.o diff --git a/source3/configure.in b/source3/configure.in index 4ed9e68d0d3..fc925ee736a 100644 --- a/source3/configure.in +++ b/source3/configure.in @@ -5895,7 +5895,9 @@ else fi AC_CHECK_LIB(pthread, pthread_mutex_lock, [WINBIND_NSS_PTHREAD="-lpthread" - AC_DEFINE(HAVE_PTHREAD, 1, [whether pthread exists])]) + AC_DEFINE(HAVE_PTHREAD, 1, [whether pthread exists]) + samba_cv_HAVE_PTHREAD=yes], + samba_cv_HAVE_PTHREAD=no) AC_SUBST(WINBIND_NSS_PTHREAD) AC_SUBST(WINBIND_NSS) @@ -6050,6 +6052,17 @@ if test x"$enable_avahi" != x"no"; then fi fi +################################################# +# Check if user wants pthreadpool support + +AC_ARG_ENABLE(pthreadpool, +[AS_HELP_STRING([--enable-pthreadpool], [Enable pthreads pool helper support (default=auto)])]) + +if test x"$enable_pthreadpool" != x"no" -a x"$samba_cv_HAVE_PTHREAD" = x"yes"; then + AC_DEFINE(WITH_PTHREADPOOL, 1, [Whether to include pthreadpool helpers]) + AC_SUBST(PTHREADPOOL_OBJ, "lib/pthreadpool.o") +fi + ################################################# # Check to see if we should use the included iniparser diff --git a/source3/include/pthreadpool.h b/source3/include/pthreadpool.h new file mode 100644 index 00000000000..7ef7ddf4192 --- /dev/null +++ b/source3/include/pthreadpool.h @@ -0,0 +1,42 @@ +/* + * Unix SMB/CIFS implementation. + * threadpool implementation based on pthreads + * Copyright (C) Volker Lendecke 2009 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#ifndef __PTHREADPOOL_H__ +#define __PTHREADPOOL_H__ + +struct pthreadpool; + +int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult); +int pthreadpool_destroy(struct pthreadpool *pool); + +/* + * Add a job to a pthreadpool. + */ +int pthreadpool_add_job(struct pthreadpool *pool, int job_id, + void (*fn)(void *private_data), void *private_data); + +/* + * Get the signalling fd out of a thread pool. This fd will become readable + * when a job is finished. The job that finished can be retrieved via + * pthreadpool_finished_job(). + */ +int pthreadpool_sig_fd(struct pthreadpool *pool); +int pthreadpool_finished_job(struct pthreadpool *pool); + +#endif diff --git a/source3/lib/pthreadpool.c b/source3/lib/pthreadpool.c new file mode 100644 index 00000000000..c5f2b41265e --- /dev/null +++ b/source3/lib/pthreadpool.c @@ -0,0 +1,505 @@ +/* + * Unix SMB/CIFS implementation. + * thread pool implementation + * Copyright (C) Volker Lendecke 2009 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "pthreadpool.h" + +struct pthreadpool_job { + struct pthreadpool_job *next; + int id; + void (*fn)(void *private_data); + void *private_data; +}; + +struct pthreadpool { + /* + * Control access to this struct + */ + pthread_mutex_t mutex; + + /* + * Threads waiting for work do so here + */ + pthread_cond_t condvar; + + /* + * List of work jobs + */ + struct pthreadpool_job *jobs, *last_job; + + /* + * pipe for signalling + */ + int sig_pipe[2]; + + /* + * indicator to worker threads that they should shut down + */ + int shutdown; + + /* + * maximum number of threads + */ + int max_threads; + + /* + * Number of threads + */ + int num_threads; + + /* + * Number of idle threads + */ + int num_idle; + + /* + * An array of threads that require joining, the array has + * "max_threads" elements. It contains "num_exited" ids. + */ + int num_exited; + pthread_t exited[1]; /* We alloc more */ +}; + +/* + * Initialize a thread pool + */ + +int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult) +{ + struct pthreadpool *pool; + size_t size; + int ret; + + size = sizeof(struct pthreadpool) + max_threads * sizeof(pthread_t); + + pool = (struct pthreadpool *)malloc(size); + if (pool == NULL) { + return ENOMEM; + } + + ret = pthread_mutex_init(&pool->mutex, NULL); + if (ret != 0) { + free(pool); + return ret; + } + + ret = pthread_cond_init(&pool->condvar, NULL); + if (ret != 0) { + pthread_mutex_destroy(&pool->mutex); + free(pool); + return ret; + } + + pool->shutdown = 0; + pool->jobs = pool->last_job = NULL; + pool->num_threads = 0; + pool->num_exited = 0; + pool->max_threads = max_threads; + pool->num_idle = 0; + pool->sig_pipe[0] = -1; + pool->sig_pipe[1] = -1; + + *presult = pool; + return 0; +} + +/* + * Create and return a file descriptor which becomes readable when a job has + * finished + */ + +int pthreadpool_sig_fd(struct pthreadpool *pool) +{ + int result, ret; + + ret = pthread_mutex_lock(&pool->mutex); + if (ret != 0) { + errno = ret; + return -1; + } + + if (pool->sig_pipe[0] != -1) { + result = pool->sig_pipe[0]; + goto done; + } + + ret = pipe(pool->sig_pipe); + if (ret == -1) { + result = -1; + goto done; + } + + result = pool->sig_pipe[0]; +done: + ret = pthread_mutex_unlock(&pool->mutex); + assert(ret == 0); + return result; +} + +/* + * Do a pthread_join() on all children that have exited, pool->mutex must be + * locked + */ +static void pthreadpool_join_children(struct pthreadpool *pool) +{ + int i; + + for (i=0; inum_exited; i++) { + pthread_join(pool->exited[i], NULL); + } + pool->num_exited = 0; +} + +/* + * Fetch a finished job number from the signal pipe + */ + +int pthreadpool_finished_job(struct pthreadpool *pool) +{ + int result, ret, fd; + ssize_t nread; + + ret = pthread_mutex_lock(&pool->mutex); + if (ret != 0) { + errno = ret; + return -1; + } + + /* + * Just some cleanup under the mutex + */ + pthreadpool_join_children(pool); + + fd = pool->sig_pipe[0]; + + ret = pthread_mutex_unlock(&pool->mutex); + assert(ret == 0); + + if (fd == -1) { + errno = EINVAL; + return -1; + } + + nread = -1; + errno = EINTR; + + while ((nread == -1) && (errno == EINTR)) { + nread = read(fd, &result, sizeof(int)); + } + + /* + * TODO: handle nread > 0 && nread < sizeof(int) + */ + + /* + * Lock the mutex to provide a memory barrier for data from the worker + * thread to the main thread. The pipe access itself does not have to + * be locked, for sizeof(int) the write to a pipe is atomic, and only + * one thread reads from it. But we need to lock the mutex briefly + * even if we don't do anything under the lock, to make sure we can + * see all memory the helper thread has written. + */ + + ret = pthread_mutex_lock(&pool->mutex); + if (ret == -1) { + errno = ret; + return -1; + } + + ret = pthread_mutex_unlock(&pool->mutex); + assert(ret == 0); + + return result; +} + +/* + * Destroy a thread pool, finishing all threads working for it + */ + +int pthreadpool_destroy(struct pthreadpool *pool) +{ + int ret, ret1; + + ret = pthread_mutex_lock(&pool->mutex); + if (ret != 0) { + return ret; + } + + if (pool->num_threads > 0) { + /* + * We have active threads, tell them to finish, wait for that. + */ + + pool->shutdown = 1; + + if (pool->num_idle > 0) { + /* + * Wake the idle threads. They will find pool->quit to + * be set and exit themselves + */ + ret = pthread_cond_broadcast(&pool->condvar); + if (ret != 0) { + pthread_mutex_unlock(&pool->mutex); + return ret; + } + } + + while ((pool->num_threads > 0) || (pool->num_exited > 0)) { + + if (pool->num_exited > 0) { + pthreadpool_join_children(pool); + continue; + } + /* + * A thread that shuts down will also signal + * pool->condvar + */ + ret = pthread_cond_wait(&pool->condvar, &pool->mutex); + if (ret != 0) { + pthread_mutex_unlock(&pool->mutex); + return ret; + } + } + } + + ret = pthread_mutex_unlock(&pool->mutex); + if (ret != 0) { + return ret; + } + ret = pthread_mutex_destroy(&pool->mutex); + ret1 = pthread_cond_destroy(&pool->condvar); + + if ((ret == 0) && (ret1 == 0)) { + free(pool); + } + + if (ret != 0) { + return ret; + } + return ret1; +} + +/* + * Prepare for pthread_exit(), pool->mutex must be locked + */ +static void pthreadpool_server_exit(struct pthreadpool *pool) +{ + pool->num_threads -= 1; + pool->exited[pool->num_exited] = pthread_self(); + pool->num_exited += 1; +} + +static void *pthreadpool_server(void *arg) +{ + struct pthreadpool *pool = (struct pthreadpool *)arg; + int res; + + res = pthread_mutex_lock(&pool->mutex); + if (res != 0) { + return NULL; + } + + while (1) { + struct timespec timeout; + struct pthreadpool_job *job; + + /* + * idle-wait at most 1 second. If nothing happens in that + * time, exit this thread. + */ + + clock_gettime(CLOCK_REALTIME, &timeout); + timeout.tv_sec += 1; + + while ((pool->jobs == NULL) && (pool->shutdown == 0)) { + + pool->num_idle += 1; + res = pthread_cond_timedwait( + &pool->condvar, &pool->mutex, &timeout); + pool->num_idle -= 1; + + if (res == ETIMEDOUT) { + + if (pool->jobs == NULL) { + /* + * we timed out and still no work for + * us. Exit. + */ + pthreadpool_server_exit(pool); + pthread_mutex_unlock(&pool->mutex); + return NULL; + } + + break; + } + assert(res == 0); + } + + job = pool->jobs; + + if (job != NULL) { + int fd = pool->sig_pipe[1]; + ssize_t written; + + /* + * Ok, there's work for us to do, remove the job from + * the pthreadpool list + */ + pool->jobs = job->next; + if (pool->last_job == job) { + pool->last_job = NULL; + } + + /* + * Do the work with the mutex unlocked :-) + */ + + res = pthread_mutex_unlock(&pool->mutex); + assert(res == 0); + + job->fn(job->private_data); + + written = sizeof(int); + + res = pthread_mutex_lock(&pool->mutex); + assert(res == 0); + + if (fd != -1) { + written = write(fd, &job->id, sizeof(int)); + } + + free(job); + + if (written != sizeof(int)) { + pthreadpool_server_exit(pool); + pthread_mutex_unlock(&pool->mutex); + return NULL; + } + } + + if ((pool->jobs == NULL) && (pool->shutdown != 0)) { + /* + * No more work to do and we're asked to shut down, so + * exit + */ + pthreadpool_server_exit(pool); + + if (pool->num_threads == 0) { + /* + * Ping the main thread waiting for all of us + * workers to have quit. + */ + pthread_cond_broadcast(&pool->condvar); + } + + pthread_mutex_unlock(&pool->mutex); + return NULL; + } + } +} + +int pthreadpool_add_job(struct pthreadpool *pool, int job_id, + void (*fn)(void *private_data), void *private_data) +{ + struct pthreadpool_job *job; + pthread_t thread_id; + int res; + sigset_t mask, omask; + + job = (struct pthreadpool_job *)malloc(sizeof(struct pthreadpool_job)); + if (job == NULL) { + return ENOMEM; + } + + job->fn = fn; + job->private_data = private_data; + job->id = job_id; + job->next = NULL; + + res = pthread_mutex_lock(&pool->mutex); + if (res != 0) { + free(job); + return res; + } + + /* + * Just some cleanup under the mutex + */ + pthreadpool_join_children(pool); + + /* + * Add job to the end of the queue + */ + if (pool->jobs == NULL) { + pool->jobs = job; + } + else { + pool->last_job->next = job; + } + pool->last_job = job; + + if (pool->num_idle > 0) { + /* + * We have idle threads, wake one. + */ + res = pthread_cond_signal(&pool->condvar); + pthread_mutex_unlock(&pool->mutex); + return res; + } + + if (pool->num_threads >= pool->max_threads) { + /* + * No more new threads, we just queue the request + */ + pthread_mutex_unlock(&pool->mutex); + return 0; + } + + /* + * Create a new worker thread. It should not receive any signals. + */ + + sigfillset(&mask); + + res = pthread_sigmask(SIG_BLOCK, &mask, &omask); + if (res != 0) { + pthread_mutex_unlock(&pool->mutex); + return res; + } + + res = pthread_create(&thread_id, NULL, pthreadpool_server, + (void *)pool); + if (res == 0) { + pool->num_threads += 1; + } + + assert(pthread_sigmask(SIG_SETMASK, &omask, NULL) == 0); + + pthread_mutex_unlock(&pool->mutex); + return res; +} -- 2.34.1