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Diffstat (limited to 'sysdeps/powerpc/nptl/elide.h')
| -rw-r--r-- | sysdeps/powerpc/nptl/elide.h | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h deleted file mode 100644 index 1c42814b71..0000000000 --- a/sysdeps/powerpc/nptl/elide.h +++ /dev/null @@ -1,125 +0,0 @@ -/* elide.h: Generic lock elision support for powerpc. - Copyright (C) 2015-2017 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 - <http://www.gnu.org/licenses/>. */ - -#ifndef ELIDE_PPC_H -# define ELIDE_PPC_H - -#ifdef ENABLE_LOCK_ELISION -# include <htm.h> -# include <elision-conf.h> - -/* Get the new value of adapt_count according to the elision - configurations. Returns true if the system should retry again or false - otherwise. */ -static inline bool -__get_new_count (uint8_t *adapt_count, int attempt) -{ - /* A persistent failure indicates that a retry will probably - result in another failure. Use normal locking now and - for the next couple of calls. */ - if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ())) - { - if (__elision_aconf.skip_lock_internal_abort > 0) - *adapt_count = __elision_aconf.skip_lock_internal_abort; - return false; - } - /* Same logic as above, but for a number of temporary failures in a - a row. */ - else if (attempt <= 1 && __elision_aconf.skip_lock_out_of_tbegin_retries > 0 - && __elision_aconf.try_tbegin > 0) - *adapt_count = __elision_aconf.skip_lock_out_of_tbegin_retries; - return true; -} - -/* CONCURRENCY NOTES: - - The evaluation of the macro expression is_lock_free encompasses one or - more loads from memory locations that are concurrently modified by other - threads. For lock elision to work, this evaluation and the rest of the - critical section protected by the lock must be atomic because an - execution with lock elision must be equivalent to an execution in which - the lock would have been actually acquired and released. Therefore, we - evaluate is_lock_free inside of the transaction that represents the - critical section for which we want to use lock elision, which ensures - the atomicity that we require. */ - -/* Returns 0 if the lock defined by is_lock_free was elided. - ADAPT_COUNT is a per-lock state variable. */ -# define ELIDE_LOCK(adapt_count, is_lock_free) \ - ({ \ - int ret = 0; \ - if (adapt_count > 0) \ - (adapt_count)--; \ - else \ - for (int i = __elision_aconf.try_tbegin; i > 0; i--) \ - { \ - if (__libc_tbegin (0)) \ - { \ - if (is_lock_free) \ - { \ - ret = 1; \ - break; \ - } \ - __libc_tabort (_ABORT_LOCK_BUSY); \ - } \ - else \ - if (!__get_new_count (&adapt_count,i)) \ - break; \ - } \ - ret; \ - }) - -# define ELIDE_TRYLOCK(adapt_count, is_lock_free, write) \ - ({ \ - int ret = 0; \ - if (__elision_aconf.try_tbegin > 0) \ - { \ - if (write) \ - __libc_tabort (_ABORT_NESTED_TRYLOCK); \ - ret = ELIDE_LOCK (adapt_count, is_lock_free); \ - } \ - ret; \ - }) - - -static inline bool -__elide_unlock (int is_lock_free) -{ - if (is_lock_free) - { - /* This code is expected to crash when trying to unlock a lock not - held by this thread. More information is available in the - __pthread_rwlock_unlock() implementation. */ - __libc_tend (0); - return true; - } - return false; -} - -# define ELIDE_UNLOCK(is_lock_free) \ - __elide_unlock (is_lock_free) - -# else - -# define ELIDE_LOCK(adapt_count, is_lock_free) 0 -# define ELIDE_TRYLOCK(adapt_count, is_lock_free, write) 0 -# define ELIDE_UNLOCK(is_lock_free) 0 - -#endif /* ENABLE_LOCK_ELISION */ - -#endif |