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| author | Jakub Jelinek <jakub@redhat.com> | 2009-07-16 07:24:50 -0700 |
|---|---|---|
| committer | Petr Baudis <pasky@suse.cz> | 2009-07-16 20:35:37 +0200 |
| commit | e875bad50a2247e6297c1b2306d87b3eb623a0be (patch) | |
| tree | 903735fafe9037f8fd7f94b3a95b87224be29809 | |
| parent | a5cceee5d55a69d82322b6ee0d17176a14b3b6bb (diff) | |
| download | glibc-e875bad50a2247e6297c1b2306d87b3eb623a0be.zip glibc-e875bad50a2247e6297c1b2306d87b3eb623a0be.tar.gz glibc-e875bad50a2247e6297c1b2306d87b3eb623a0be.tar.bz2 | |
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.
(cherry picked from commit bea0ac1d8703091294fe5822d982591c849b5458)
| -rw-r--r-- | ChangeLog | 13 | ||||
| -rw-r--r-- | include/atomic.h | 32 | ||||
| -rw-r--r-- | malloc/malloc.c | 3 |
3 files changed, 35 insertions, 13 deletions
@@ -1,3 +1,16 @@ +2009-07-13 Jakub Jelinek <jakub@redhat.com> + + * include/atomic.h (catomic_compare_and_exchange_val_rel): If arch + overrides atomic_compare_and_exchange_val_rel, define to + atomic_compare_and_exchange_val_rel by default, otherwise default + to catomic_compare_and_exchange_val_acq. + (catomic_compare_and_exchange_bool_rel): If arch overrides + atomic_compare_and_exchange_bool_rel, define to + atomic_compare_and_exchange_bool_rel by default. + * malloc/malloc.c (_int_free): Revert 2009-07-02 change. + Use catomic_compare_and_exchange_val_rel instead of + catomic_compare_and_exchange_val_acq. + 2009-07-07 H.J. Lu <hongjiu.lu@intel.com> * elf/Makefile: Don't build modules for tst-audit3 for anything diff --git a/include/atomic.h b/include/atomic.h index 9366f78..37d0111 100644 --- a/include/atomic.h +++ b/include/atomic.h @@ -107,14 +107,19 @@ #endif -#ifndef atomic_compare_and_exchange_val_rel -# define atomic_compare_and_exchange_val_rel(mem, newval, oldval) \ - atomic_compare_and_exchange_val_acq (mem, newval, oldval) +#ifndef catomic_compare_and_exchange_val_rel +# ifndef atomic_compare_and_exchange_val_rel +# define catomic_compare_and_exchange_val_rel(mem, newval, oldval) \ + catomic_compare_and_exchange_val_acq (mem, newval, oldval) +# else +# define catomic_compare_and_exchange_val_rel(mem, newval, oldval) \ + atomic_compare_and_exchange_val_rel (mem, newval, oldval) +# endif #endif -#ifndef catomic_compare_and_exchange_val_rel -# define catomic_compare_and_exchange_val_rel(mem, newval, oldval) \ +#ifndef atomic_compare_and_exchange_val_rel +# define atomic_compare_and_exchange_val_rel(mem, newval, oldval) \ atomic_compare_and_exchange_val_acq (mem, newval, oldval) #endif @@ -155,15 +160,20 @@ #endif -#ifndef atomic_compare_and_exchange_bool_rel -# define atomic_compare_and_exchange_bool_rel(mem, newval, oldval) \ - atomic_compare_and_exchange_bool_acq (mem, newval, oldval) +#ifndef catomic_compare_and_exchange_bool_rel +# ifndef atomic_compare_and_exchange_bool_rel +# define catomic_compare_and_exchange_bool_rel(mem, newval, oldval) \ + catomic_compare_and_exchange_bool_acq (mem, newval, oldval) +# else +# define catomic_compare_and_exchange_bool_rel(mem, newval, oldval) \ + atomic_compare_and_exchange_bool_rel (mem, newval, oldval) +# endif #endif -#ifndef catomic_compare_and_exchange_bool_rel -# define catomic_compare_and_exchange_bool_rel(mem, newval, oldval) \ - catomic_compare_and_exchange_bool_acq (mem, newval, oldval) +#ifndef atomic_compare_and_exchange_bool_rel +# define atomic_compare_and_exchange_bool_rel(mem, newval, oldval) \ + atomic_compare_and_exchange_bool_acq (mem, newval, oldval) #endif diff --git a/malloc/malloc.c b/malloc/malloc.c index 703dcb5..bd44dee 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4802,9 +4802,8 @@ _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). */ |