glibc/sysdeps/unix/sysv/linux/powerpc/elision-lock.c
Paul Eggert 5a82c74822 Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:

sed -ri '
  s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
  s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
  $(find $(git ls-files) -prune -type f \
      ! -name '*.po' \
      ! -name 'ChangeLog*' \
      ! -path COPYING ! -path COPYING.LIB \
      ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
      ! -path manual/texinfo.tex ! -path scripts/config.guess \
      ! -path scripts/config.sub ! -path scripts/install-sh \
      ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
      ! -path INSTALL ! -path  locale/programs/charmap-kw.h \
      ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
      ! '(' -name configure \
            -execdir test -f configure.ac -o -f configure.in ';' ')' \
      ! '(' -name preconfigure \
            -execdir test -f preconfigure.ac ';' ')' \
      -print)

and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:

  chmod a+x sysdeps/unix/sysv/linux/riscv/configure
  # Omit irrelevant whitespace and comment-only changes,
  # perhaps from a slightly-different Autoconf version.
  git checkout -f \
    sysdeps/csky/configure \
    sysdeps/hppa/configure \
    sysdeps/riscv/configure \
    sysdeps/unix/sysv/linux/csky/configure
  # Omit changes that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
  git checkout -f \
    sysdeps/powerpc/powerpc64/ppc-mcount.S \
    sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
  # Omit change that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
  git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 02:43:31 -07:00

87 lines
2.6 KiB
C

/* elision-lock.c: Elided pthread mutex lock.
Copyright (C) 2015-2019 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
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <pthread.h>
#include <pthreadP.h>
#include <lowlevellock.h>
#include <elision-conf.h>
#include "htm.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 *lock, short *adapt_count, EXTRAARG int pshared)
{
/* adapt_count is accessed concurrently but is just a hint. Thus,
use atomic accesses but relaxed MO is sufficient. */
if (atomic_load_relaxed (adapt_count) > 0)
{
goto use_lock;
}
for (int i = aconf.try_tbegin; i > 0; i--)
{
if (__libc_tbegin (0))
{
if (*lock == 0)
return 0;
/* Lock was busy. Fall back to normal locking. */
__libc_tabort (_ABORT_LOCK_BUSY);
}
else
{
/* 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 (aconf.skip_lock_internal_abort > 0)
atomic_store_relaxed (adapt_count,
aconf.skip_lock_internal_abort);
goto use_lock;
}
}
}
/* Fall back to locks for a bit if retries have been exhausted */
if (aconf.try_tbegin > 0 && aconf.skip_lock_out_of_tbegin_retries > 0)
atomic_store_relaxed (adapt_count,
aconf.skip_lock_out_of_tbegin_retries);
use_lock:
return LLL_LOCK ((*lock), pshared);
}