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authorUlrich Drepper <drepper@redhat.com>2002-06-21 05:32:43 +0000
committerUlrich Drepper <drepper@redhat.com>2002-06-21 05:32:43 +0000
commit9b17bc94bc580d5893a9c93050bb3d8bf160e4ee (patch)
tree027f0fe82f83a8604f381bd9b641c51ec482eebe /linuxthreads
parente6ac0e78f1fd258b74ae9175ef17460968b7f0f5 (diff)
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Update.
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.
Diffstat (limited to 'linuxthreads')
-rw-r--r--linuxthreads/ChangeLog8
-rw-r--r--linuxthreads/spinlock.c60
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