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-rw-r--r--src/thread/__lock.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/src/thread/__lock.c b/src/thread/__lock.c
new file mode 100644
index 00000000..557c6a62
--- /dev/null
+++ b/src/thread/__lock.c
@@ -0,0 +1,12 @@
+#define SYSCALL_RETURN_ERRNO
+#include "pthread_impl.h"
+
+void __lock(volatile int *l)
+{
+ int spins=100000;
+ /* Do not use futexes because we insist that unlocking is a simple
+ * assignment to optimize non-pathological code with no contention. */
+ while (a_xchg(l, 1))
+ if (spins) spins--, a_spin();
+ else syscall0(__NR_sched_yield);
+}