diff options
| author | Niels de Vos <ndevos@redhat.com> | 2017-03-29 13:44:03 +0200 |
|---|---|---|
| committer | Jeff Darcy <jeff@pl.atyp.us> | 2017-04-05 09:14:26 -0400 |
| commit | 93e3c9abce1a02ac724afa382751852fa5edf713 (patch) | |
| tree | 887c599c2a31ab65a2f0b2440e5f3fe8b6061afc /configure.ac | |
| parent | d6b88e9b8b02813620c3c1a2ea49d58d29062b3e (diff) | |
libglusterfs: provide standardized atomic operations
The current macros ATOMIC_INCREMENT() and ATOMIC_DECREMENT() expect a
lock as first argument. There are at least two issues with this
approach:
1. this lock is unused on architectures that have atomic operations
2. some structures use a single lock for multiple variables
By defining a gf_atomic_t type, the unused lock can be removed, saving a
few bytes on modern architectures.
Because the gf_atomic_t type locates the lock for the variable (in case
of older architectures), each variable is protected the same on all
architectures. This makes the behaviour across all architectures more
equal (per variable locking, by a gf_lock_t or compiler optimization).
BUG: 1437037
Change-Id: Ic164892b06ea676e6a9566f8a98b7faf0efe76d6
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: https://review.gluster.org/16963
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Jeff Darcy <jeff@pl.atyp.us>
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/configure.ac b/configure.ac index c7b6c38c002..c2d03e7ee6a 100644 --- a/configure.ac +++ b/configure.ac @@ -956,16 +956,19 @@ AC_SUBST(ARGP_STANDALONE_CPPFLAGS) AC_SUBST(ARGP_STANDALONE_LDADD) AC_SUBST(ARGP_STANDALONE_DIR) -# Check for atomic operation support -echo -n "checking for atomic operation support... " -AC_LINK_IFELSE([AC_LANG_SOURCE([[int main() { long int a = 4; __sync_fetch_and_add_8 (&a, 1); }]])], - [have_sync_fetch_and_add_8=yes], [have_sync_fetch_and_add_8=no]) -if test "x${have_sync_fetch_and_add_8}" = "xyes"; then - echo "yes" - AC_DEFINE(HAVE_ATOMIC_BUILTINS, 1, [have atomic builtins]) -else - echo "no" +dnl Check for atomic operation support +AC_CHECK_FUNC([__atomic_load], [have_atomic_builtins]) +if test "x${have_atomic_builtins}" = "xyes"; then + AC_DEFINE(HAVE_ATOMIC_BUILTINS, 1, [define if __atomic_*() builtins are available]) +fi +AC_SUBST(HAVE_ATOMIC_BUILTINS) + +dnl __sync_*() will not be needed if __atomic_*() is available +AC_CHECK_FUNC([__sync_fetch_and_add], [have_sync_builtins]) +if test "x${have_sync_builtind}" = "xyes"; then + AC_DEFINE(HAVE_SYNC_BUILTINS, 1, [define if __sync_*() builtins are available]) fi +AC_SUBST(HAVE_SYNC_BUILTINS) AC_CHECK_HEADER([malloc.h], AC_DEFINE(HAVE_MALLOC_H, 1, [have malloc.h])) |