diff options
Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/s390/elision-lock.c')
| -rw-r--r-- | nptl/sysdeps/unix/sysv/linux/s390/elision-lock.c | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/s390/elision-lock.c b/nptl/sysdeps/unix/sysv/linux/s390/elision-lock.c deleted file mode 100644 index ba5338fbb9..0000000000 --- a/nptl/sysdeps/unix/sysv/linux/s390/elision-lock.c +++ /dev/null @@ -1,119 +0,0 @@ -/* Elided pthread mutex lock. - Copyright (C) 2014 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/>. */ - -#include <pthread.h> -#include <pthreadP.h> -#include <lowlevellock.h> -#include <htmintrin.h> -#include <elision-conf.h> -#include <stdint.h> - -#if !defined(LLL_LOCK) && !defined(EXTRAARG) -/* Make sure the configuration code is always linked in for static - libraries. */ -#include "elision-conf.c" -#endif - -#ifndef EXTRAARG -#define EXTRAARG -#endif -#ifndef LLL_LOCK -#define LLL_LOCK(a,b) lll_lock(a,b), 0 -#endif - -#define aconf __elision_aconf - -/* Adaptive lock using transactions. - By default the lock region is run as a transaction, and when it - aborts or the lock is busy the lock adapts itself. */ - -int -__lll_lock_elision (int *futex, short *adapt_count, EXTRAARG int private) -{ - if (*adapt_count > 0) - { - /* Lost updates are possible, but harmless. Due to races this might lead - to *adapt_count becoming less than zero. */ - (*adapt_count)--; - goto use_lock; - } - - __asm__ volatile (".machinemode \"zarch_nohighgprs\"\n\t" - ".machine \"all\"" - : : : "memory"); - - int try_tbegin; - for (try_tbegin = aconf.try_tbegin; - try_tbegin > 0; - try_tbegin--) - { - unsigned status; - if (__builtin_expect - ((status = __builtin_tbegin((void *)0)) == _HTM_TBEGIN_STARTED, 1)) - { - if (*futex == 0) - return 0; - /* Lock was busy. Fall back to normal locking. */ - if (__builtin_expect (__builtin_tx_nesting_depth (), 1)) - { - /* In a non-nested transaction there is no need to abort, - which is expensive. */ - __builtin_tend (); - if (aconf.skip_lock_busy > 0) - *adapt_count = aconf.skip_lock_busy; - goto use_lock; - } - else /* nesting depth is > 1 */ - { - /* A nested transaction will abort eventually because it - cannot make any progress before *futex changes back to 0. - So we may as well abort immediately. - This persistently aborts the outer transaction to force - the outer mutex use the default lock instead of retrying - with transactions until the try_tbegin of the outer mutex - is zero. - The adapt_count of this inner mutex is not changed, - because using the default lock with the inner mutex - would abort the outer transaction. - */ - __builtin_tabort (_HTM_FIRST_USER_ABORT_CODE | 1); - } - } - else - { - if (status != _HTM_TBEGIN_TRANSIENT) - { - /* A persistent abort (cc 1 or 3) indicates that a retry is - probably futile. Use the normal locking now and for the - next couple of calls. - Be careful to avoid writing to the lock. */ - if (aconf.skip_lock_internal_abort > 0) - *adapt_count = aconf.skip_lock_internal_abort; - goto use_lock; - } - } - } - - /* Same logic as above, but for for a number of temporary failures in a - row. */ - if (aconf.skip_lock_out_of_tbegin_retries > 0 && aconf.try_tbegin > 0) - *adapt_count = aconf.skip_lock_out_of_tbegin_retries; - - use_lock: - return LLL_LOCK ((*futex), private); -} |