mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 01:00:07 +00:00
95 lines
3.3 KiB
C
95 lines
3.3 KiB
C
/* Copyright (C) 2003-2023 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C 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 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C 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 the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <endian.h>
|
|
#include <errno.h>
|
|
#include <sysdep.h>
|
|
#include <futex-internal.h>
|
|
#include <pthread.h>
|
|
#include <pthreadP.h>
|
|
#include <stap-probe.h>
|
|
#include <atomic.h>
|
|
|
|
#include <shlib-compat.h>
|
|
|
|
#include "pthread_cond_common.c"
|
|
|
|
|
|
/* We do the following steps from __pthread_cond_signal in one critical
|
|
section: (1) signal all waiters in G1, (2) close G1 so that it can become
|
|
the new G2 and make G2 the new G1, and (3) signal all waiters in the new
|
|
G1. We don't need to do all these steps if there are no waiters in G1
|
|
and/or G2. See __pthread_cond_signal for further details. */
|
|
int
|
|
___pthread_cond_broadcast (pthread_cond_t *cond)
|
|
{
|
|
LIBC_PROBE (cond_broadcast, 1, cond);
|
|
|
|
unsigned int wrefs = atomic_load_relaxed (&cond->__data.__wrefs);
|
|
if (wrefs >> 3 == 0)
|
|
return 0;
|
|
int private = __condvar_get_private (wrefs);
|
|
|
|
__condvar_acquire_lock (cond, private);
|
|
|
|
unsigned long long int wseq = __condvar_load_wseq_relaxed (cond);
|
|
unsigned int g2 = wseq & 1;
|
|
unsigned int g1 = g2 ^ 1;
|
|
wseq >>= 1;
|
|
bool do_futex_wake = false;
|
|
|
|
/* Step (1): signal all waiters remaining in G1. */
|
|
if (cond->__data.__g_size[g1] != 0)
|
|
{
|
|
/* Add as many signals as the remaining size of the group. */
|
|
atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
|
|
cond->__data.__g_size[g1] << 1);
|
|
cond->__data.__g_size[g1] = 0;
|
|
|
|
/* We need to wake G1 waiters before we quiesce G1 below. */
|
|
/* TODO Only set it if there are indeed futex waiters. We could
|
|
also try to move this out of the critical section in cases when
|
|
G2 is empty (and we don't need to quiesce). */
|
|
futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
|
|
}
|
|
|
|
/* G1 is complete. Step (2) is next unless there are no waiters in G2, in
|
|
which case we can stop. */
|
|
if (__condvar_quiesce_and_switch_g1 (cond, wseq, &g1, private))
|
|
{
|
|
/* Step (3): Send signals to all waiters in the old G2 / new G1. */
|
|
atomic_fetch_add_relaxed (cond->__data.__g_signals + g1,
|
|
cond->__data.__g_size[g1] << 1);
|
|
cond->__data.__g_size[g1] = 0;
|
|
/* TODO Only set it if there are indeed futex waiters. */
|
|
do_futex_wake = true;
|
|
}
|
|
|
|
__condvar_release_lock (cond, private);
|
|
|
|
if (do_futex_wake)
|
|
futex_wake (cond->__data.__g_signals + g1, INT_MAX, private);
|
|
|
|
return 0;
|
|
}
|
|
versioned_symbol (libc, ___pthread_cond_broadcast,
|
|
pthread_cond_broadcast, GLIBC_2_3_2);
|
|
libc_hidden_ver (___pthread_cond_broadcast, __pthread_cond_broadcast)
|
|
#ifndef SHARED
|
|
strong_alias (___pthread_cond_broadcast, __pthread_cond_broadcast)
|
|
#endif
|