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5a82c74822
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
62 lines
2.7 KiB
C
62 lines
2.7 KiB
C
/* Commit an elided pthread lock.
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Copyright (C) 2014-2019 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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<https://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 *futex, short *adapt_count, int private)
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{
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/* If the lock is free, we elided the lock earlier. This does not
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necessarily mean that we are in a transaction, because the user code may
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have closed the transaction, but that is impossible to detect reliably.
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Relaxed MO access to futex is sufficient because a correct program
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will only release a lock it has acquired; therefore, it must either
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changed the futex word's value to something !=0 or it must have used
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elision; these are actions by the same thread, so these actions are
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sequenced-before the relaxed load (and thus also happens-before the
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relaxed load). Therefore, relaxed MO is sufficient. */
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if (atomic_load_relaxed (futex) == 0)
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{
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__libc_tend ();
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}
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else
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{
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/* Update the adapt_count while unlocking before completing the critical
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section. adapt_count is accessed concurrently outside of a
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transaction or a critical section (e.g. in elision-lock.c). So we need
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to use atomic accesses. However, the value of adapt_count is just a
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hint, so relaxed MO accesses are sufficient.
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If adapt_count would be decremented while locking, multiple
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CPUs, trying to lock the acquired mutex, will decrement adapt_count to
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zero and another CPU will try to start a transaction, which will be
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immediately aborted as the mutex is locked.
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The update of adapt_count is done before releasing the lock as POSIX'
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mutex destruction requirements disallow accesses to the mutex after it
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has been released and thus could have been acquired or destroyed by
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another thread. */
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short adapt_count_val = atomic_load_relaxed (adapt_count);
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if (adapt_count_val > 0)
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atomic_store_relaxed (adapt_count, adapt_count_val - 1);
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lll_unlock ((*futex), private);
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}
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return 0;
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}
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