glibc/sysdeps/unix/sysv/linux/powerpc/elision-trylock.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

70 lines
2.1 KiB
C

/* elision-trylock.c: Lock eliding trylock for pthreads.
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 <pthread.h>
#include <pthreadP.h>
#include <lowlevellock.h>
#include <elision-conf.h>
#include "htm.h"
#define aconf __elision_aconf
/* Try to elide a futex trylock. FUTEX is the futex variable. ADAPT_COUNT is
the adaptation counter in the mutex. */
int
__lll_trylock_elision (int *futex, short *adapt_count)
{
/* Implement POSIX semantics by forbiding nesting elided trylocks. */
__libc_tabort (_ABORT_NESTED_TRYLOCK);
/* Only try a transaction if it's worth it. */
if (atomic_load_relaxed (adapt_count) > 0)
{
goto use_lock;
}
if (__libc_tbegin (0))
{
if (*futex == 0)
return 0;
/* Lock was busy. This is never a nested transaction.
End it, and set the adapt count. */
__libc_tend (0);
if (aconf.skip_lock_busy > 0)
atomic_store_relaxed (adapt_count, aconf.skip_lock_busy);
}
else
{
if (_TEXASRU_FAILURE_PERSISTENT (__builtin_get_texasru ()))
{
/* 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 (aconf.skip_trylock_internal_abort > 0)
atomic_store_relaxed (adapt_count,
aconf.skip_trylock_internal_abort);
}
}
use_lock:
return lll_trylock (*futex);
}