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8ba6ad703c
900778283a ("htl: make pthread_spin_lock really spin") made
pthread_spin_lock really spin and not block, but the current users of
__pthread_spin_lock were assuming that it blocks, i.e. they use it as a
lightweight mutex fitting in just one int.
__pthread_spin_wait provides that support back.
71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
/* pthread_barrier_wait. Generic version.
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Copyright (C) 2002-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <pthread.h>
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#include <assert.h>
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#include <pt-internal.h>
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int
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pthread_barrier_wait (pthread_barrier_t *barrier)
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{
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__pthread_spin_wait (&barrier->__lock);
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if (--barrier->__pending == 0)
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{
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barrier->__pending = barrier->__count;
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if (barrier->__count == 1)
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__pthread_spin_unlock (&barrier->__lock);
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else
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{
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struct __pthread *wakeup;
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unsigned n = 0;
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__pthread_queue_iterate (barrier->__queue, wakeup)
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n++;
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{
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struct __pthread *wakeups[n];
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unsigned i = 0;
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__pthread_dequeuing_iterate (barrier->__queue, wakeup)
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wakeups[i++] = wakeup;
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barrier->__queue = NULL;
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__pthread_spin_unlock (&barrier->__lock);
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for (i = 0; i < n; i++)
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__pthread_wakeup (wakeups[i]);
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}
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}
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return PTHREAD_BARRIER_SERIAL_THREAD;
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}
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else
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{
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struct __pthread *self = _pthread_self ();
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/* Add ourselves to the list of waiters. */
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__pthread_enqueue (&barrier->__queue, self);
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__pthread_spin_unlock (&barrier->__lock);
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__pthread_block (self);
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return 0;
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}
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}
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