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authorJakub Jelinek <jakub@redhat.com>2009-07-16 07:24:50 -0700
committerUlrich Drepper <drepper@redhat.com>2009-07-16 07:24:50 -0700
commitbea0ac1d8703091294fe5822d982591c849b5458 (patch)
tree1d7b20d187c218c9113de06d9c295ed9039f18af /malloc
parent55c4ce6885b577e2b29a4de674d4062a6882afe8 (diff)
Use rel semantics of cas instead of acq semantics with full barrier before it in _int_free
The following patch fixes catomic_compare_and_exchange_*_rel definitions (which were never used and weren't correct) and uses catomic_compare_and_exchange_val_rel in _int_free. Comparing to the pre-2009-07-02 --enable-experimental-malloc state the generated code should be identical on all arches other than ppc/ppc64 and on ppc/ppc64 should use lwsync instead of isync barrier.
Diffstat (limited to 'malloc')
-rw-r--r--malloc/malloc.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 70e4e58845..0c0182ec0b 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -4822,9 +4822,8 @@ _int_free(mstate av, mchunkptr p)
goto errout;
}
p->fd = fd = old;
- atomic_full_barrier ();
}
- while ((old = catomic_compare_and_exchange_val_acq (fb, p, fd)) != fd);
+ while ((old = catomic_compare_and_exchange_val_rel (fb, p, fd)) != fd);
#else
/* Another simple check: make sure the top of the bin is not the
record we are going to add (i.e., double free). */