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authorRich Felker <dalias@aerifal.cx>2011-09-27 13:50:29 -0400
committerRich Felker <dalias@aerifal.cx>2011-09-27 13:50:29 -0400
commit60164570111873175111cf8a5b973375e492eee9 (patch)
tree1557931c4e0bacd2be217965be08031d5e3a4e51 /src/internal
parent3f39c9b3130cd6c142d358159879b799370a6663 (diff)
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process-shared barrier support, based on discussion with bdonlan
this implementation is rather heavy-weight, but it's the first
solution i've found that's actually correct. all waiters actually wait
twice at the barrier so that they can synchronize exit, and they hold
a "vm lock" that prevents changes to virtual memory mappings (and
blocks pthread_barrier_destroy) until all waiters are finished
inspecting the barrier.

thus, it is safe for any thread to destroy and/or unmap the barrier's
memory as soon as pthread_barrier_wait returns, without further
synchronization.
Diffstat (limited to 'src/internal')
-rw-r--r--src/internal/pthread_impl.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index bbb4502f..82d62426 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -73,10 +73,12 @@ struct __timer {
 #define _c_waiters2 __u.__i[7]
 #define _rw_lock __u.__i[0]
 #define _rw_waiters __u.__i[1]
-#define _b_inst __u.__p[0]
+#define _b_lock __u.__i[0]
+#define _b_waiters __u.__i[1]
 #define _b_limit __u.__i[2]
-#define _b_lock __u.__i[3]
-#define _b_waiters __u.__i[4]
+#define _b_count __u.__i[3]
+#define _b_seq __u.__i[4]
+#define _b_inst __u.__p[4]
 
 #include "pthread_arch.h"