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42bf1c8971
Work around a GCC behavior with hardware transactional memory built-ins. GCC doesn't treat the PowerPC transactional built-ins as compiler barriers, moving instructions past the transaction boundaries and altering their atomicity.
41 lines
1.4 KiB
C
41 lines
1.4 KiB
C
/* elision-unlock.c: Commit an elided pthread lock.
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Copyright (C) 2015-2016 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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<http://www.gnu.org/licenses/>. */
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#include "pthreadP.h"
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#include "lowlevellock.h"
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#include "htm.h"
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int
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__lll_unlock_elision (int *lock, short *adapt_count, int pshared)
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{
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/* When the lock was free we're in a transaction. */
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if (*lock == 0)
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__libc_tend (0);
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else
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{
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lll_unlock ((*lock), pshared);
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/* Update the adapt count AFTER completing the critical section.
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Doing this here prevents unneeded stalling when entering
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a critical section. Saving about 8% runtime on P8. */
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if (*adapt_count > 0)
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(*adapt_count)--;
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}
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return 0;
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}
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