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samba-mirror/source3/lib/pthreadpool/pthreadpool_sync.c
Volker Lendecke c5d07df6ab pthreadpool: Allow multiple jobs to be received
This can avoid syscalls when multiple jobs are finished simultaneously

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2014-03-27 06:06:11 +01:00

182 lines
3.6 KiB
C

/*
* Unix SMB/CIFS implementation.
* sync dummy implementation of the pthreadpool API
* 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 <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <assert.h>
#include <fcntl.h>
#include <sys/time.h>
#include "pthreadpool.h"
struct pthreadpool {
/*
* pipe for signalling
*/
int sig_pipe[2];
/*
* Have we sent something into the pipe that has not been
* retrieved yet?
*/
int pipe_busy;
/*
* Jobids that we have not sent into the pipe yet
*/
size_t num_ids;
int *ids;
};
int pthreadpool_init(unsigned max_threads, struct pthreadpool **presult)
{
struct pthreadpool *pool;
int ret;
pool = (struct pthreadpool *)calloc(1, sizeof(struct pthreadpool));
if (pool == NULL) {
return ENOMEM;
}
ret = pipe(pool->sig_pipe);
if (ret == -1) {
int err = errno;
free(pool);
return err;
}
*presult = pool;
return 0;
}
int pthreadpool_signal_fd(struct pthreadpool *pool)
{
return pool->sig_pipe[0];
}
static int pthreadpool_write_to_pipe(struct pthreadpool *pool)
{
ssize_t written;
if (pool->pipe_busy) {
return 0;
}
if (pool->num_ids == 0) {
return 0;
}
written = -1;
errno = EINTR;
while ((written == -1) && (errno == EINTR)) {
written = write(pool->sig_pipe[1], &pool->ids[0], sizeof(int));
}
if (written == -1) {
return errno;
}
if (written != sizeof(int)) {
/*
* If a single int only partially fits into the pipe,
* we can assume ourselves pretty broken
*/
close(pool->sig_pipe[1]);
pool->sig_pipe[1] = -1;
return EIO;
}
if (pool->num_ids > 1) {
memmove(pool->ids, pool->ids+1, sizeof(int) * (pool->num_ids-1));
}
pool->num_ids -= 1;
pool->pipe_busy = 1;
return 0;
}
int pthreadpool_add_job(struct pthreadpool *pool, int job_id,
void (*fn)(void *private_data), void *private_data)
{
int *tmp;
if (pool->sig_pipe[1] == -1) {
return EIO;
}
fn(private_data);
tmp = realloc(pool->ids, sizeof(int) * (pool->num_ids+1));
if (tmp == NULL) {
return ENOMEM;
}
pool->ids = tmp;
pool->ids[pool->num_ids] = job_id;
pool->num_ids += 1;
return pthreadpool_write_to_pipe(pool);
}
int pthreadpool_finished_jobs(struct pthreadpool *pool, int *jobids,
unsigned num_jobids)
{
ssize_t to_read, nread;
int ret;
nread = -1;
errno = EINTR;
to_read = sizeof(int) * num_jobids;
while ((nread == -1) && (errno == EINTR)) {
nread = read(pool->sig_pipe[0], jobids, to_read);
}
if (nread == -1) {
return -errno;
}
if ((nread % sizeof(int)) != 0) {
return -EINVAL;
}
pool->pipe_busy = 0;
ret = pthreadpool_write_to_pipe(pool);
if (ret != 0) {
return -ret;
}
return nread / sizeof(int);
}
int pthreadpool_destroy(struct pthreadpool *pool)
{
if (pool->sig_pipe[0] != -1) {
close(pool->sig_pipe[0]);
pool->sig_pipe[0] = -1;
}
if (pool->sig_pipe[1] != -1) {
close(pool->sig_pipe[1]);
pool->sig_pipe[1] = -1;
}
free(pool->ids);
free(pool);
return 0;
}