diff options
| -rw-r--r-- | linuxthreads/ChangeLog | 8 | ||||
| -rw-r--r-- | linuxthreads/spinlock.c | 60 |
2 files changed, 11 insertions, 57 deletions
diff --git a/linuxthreads/ChangeLog b/linuxthreads/ChangeLog index c832816..fa1c8b0 100644 --- a/linuxthreads/ChangeLog +++ b/linuxthreads/ChangeLog @@ -1,3 +1,11 @@ +2002-06-20 Ulrich Drepper <drepper@redhat.com> + + * spinlock.c (wait_node_alloc): We cannot use compare-and-exchange. + Unconditionally use the code using spinlock. Use __pthread_release + to free a spinlock. + (wait_node_free): Likewise. + (__pthread_acquire, __pthread_release): Unconditionally define. + 2002-06-07 Jakub Jelinek <jakub@redhat.com> * sysdeps/ia64/pt-machine.h (MEMORY_BARRIER): Fix typo. diff --git a/linuxthreads/spinlock.c b/linuxthreads/spinlock.c index 3e16825..582a95c 100644 --- a/linuxthreads/spinlock.c +++ b/linuxthreads/spinlock.c @@ -24,7 +24,6 @@ #include "spinlock.h" #include "restart.h" -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP static void __pthread_acquire(int * spinlock); static inline void __pthread_release(int * spinlock) @@ -33,7 +32,6 @@ static inline void __pthread_release(int * spinlock) *spinlock = __LT_SPINLOCK_INIT; __asm __volatile ("" : "=m" (*spinlock) : "0" (*spinlock)); } -#endif /* The status field of a spinlock is a pointer whose least significant @@ -275,9 +273,7 @@ struct wait_node { }; static long wait_node_free_list; -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP static int wait_node_free_list_spinlock; -#endif /* Allocate a new node from the head of the free list using an atomic operation, or else using malloc if that list is empty. A fundamental @@ -287,15 +283,6 @@ static int wait_node_free_list_spinlock; static struct wait_node *wait_node_alloc(void) { -#if defined HAS_COMPARE_AND_SWAP - long oldvalue, newvalue; -#endif - -#if defined TEST_FOR_COMPARE_AND_SWAP - if (!__pthread_has_cas) -#endif -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP - { struct wait_node *new_node = 0; __pthread_acquire(&wait_node_free_list_spinlock); @@ -304,29 +291,12 @@ static struct wait_node *wait_node_alloc(void) wait_node_free_list = (long) new_node->next; } WRITE_MEMORY_BARRIER(); - wait_node_free_list_spinlock = 0; + __pthread_release(&wait_node_free_list_spinlock); if (new_node == 0) return malloc(sizeof *wait_node_alloc()); return new_node; - } -#endif - -#if defined HAS_COMPARE_AND_SWAP - do { - oldvalue = wait_node_free_list; - - if (oldvalue == 0) - return malloc(sizeof *wait_node_alloc()); - - /* Ensure we don't read stale next link through oldvalue pointer. */ - READ_MEMORY_BARRIER(); - newvalue = (long) ((struct wait_node *) oldvalue)->next; - } while (! __compare_and_swap(&wait_node_free_list, oldvalue, newvalue)); - - return (struct wait_node *) oldvalue; -#endif } /* Return a node to the head of the free list using an atomic @@ -334,33 +304,12 @@ static struct wait_node *wait_node_alloc(void) static void wait_node_free(struct wait_node *wn) { -#if defined HAS_COMPARE_AND_SWAP - long oldvalue, newvalue; -#endif - -#if defined TEST_FOR_COMPARE_AND_SWAP - if (!__pthread_has_cas) -#endif -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP - { __pthread_acquire(&wait_node_free_list_spinlock); wn->next = (struct wait_node *) wait_node_free_list; wait_node_free_list = (long) wn; WRITE_MEMORY_BARRIER(); - wait_node_free_list_spinlock = 0; + __pthread_release(&wait_node_free_list_spinlock); return; - } -#endif - -#if defined HAS_COMPARE_AND_SWAP - do { - oldvalue = wait_node_free_list; - wn->next = (struct wait_node *) oldvalue; - newvalue = (long) wn; - /* Ensure node contents are written before we swap it into the list. */ - WRITE_MEMORY_BARRIER(); - } while (! __compare_and_swap(&wait_node_free_list, oldvalue, newvalue)); -#endif } #if defined HAS_COMPARE_AND_SWAP @@ -730,8 +679,7 @@ int __pthread_compare_and_swap(long * ptr, long oldval, long newval, return res; } -/* This function is called if the inlined test-and-set - in __pthread_compare_and_swap() failed */ +#endif /* The retry strategy is as follows: - We test and set the spinlock MAX_SPIN_COUNT times, calling @@ -770,5 +718,3 @@ static void __pthread_acquire(int * spinlock) } } } - -#endif |