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4a07fbb689
Replace atomic_decrement_and_test with atomic_fetch_add_relaxed. These are simple counters which do not protect any shared data from concurrent accesses. Also remove the unused file cond-perf.c. Passes regress on AArch64. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
72 lines
2.6 KiB
C
72 lines
2.6 KiB
C
/* Deallocate a thread structure.
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Copyright (C) 2000-2022 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 <assert.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <pt-internal.h>
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#include <atomic.h>
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/* List of thread structures corresponding to free thread IDs. */
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extern struct __pthread *__pthread_free_threads;
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extern pthread_mutex_t __pthread_free_threads_lock;
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/* Deallocate the content of the thread structure for PTHREAD. */
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void
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__pthread_dealloc (struct __pthread *pthread)
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{
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if (atomic_fetch_add_relaxed (&pthread->nr_refs, -1) != 1)
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return;
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/* Withdraw this thread from the thread ID lookup table. */
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__pthread_setid (pthread->thread, NULL);
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/* Mark the thread as terminated. We broadcast the condition
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here to prevent pthread_join from waiting for this thread to
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exit where it was never really started. Such a call to
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pthread_join is completely bogus, but unfortunately allowed
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by the standards. */
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__pthread_mutex_lock (&pthread->state_lock);
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if (pthread->state != PTHREAD_EXITED)
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__pthread_cond_broadcast (&pthread->state_cond);
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__pthread_mutex_unlock (&pthread->state_lock);
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/* We do not actually deallocate the thread structure, but add it to
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a list of re-usable thread structures. */
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__pthread_mutex_lock (&__pthread_free_threads_lock);
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__pthread_enqueue (&__pthread_free_threads, pthread);
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__pthread_mutex_unlock (&__pthread_free_threads_lock);
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}
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/* Confirm deallocation of the thread structure for PTHREAD. */
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void
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__pthread_dealloc_finish (struct __pthread *pthread)
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{
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/* Setting PTHREAD->TERMINATED makes this TCB
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available for reuse. After that point, we can no longer assume
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that PTHREAD is valid.
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Note that it is safe to not lock this update to PTHREAD->STATE:
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the only way that it can now be accessed is in __pthread_alloc,
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which reads this variable. */
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pthread->terminated = TRUE;
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}
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