1.0.0.10:

[sbcl.git] / src / runtime / linux-os.c

diff --git a/src/runtime/linux-os.c b/src/runtime/linux-os.c
index faf1a47..fbc888e 100644 (file)
--- a/src/runtime/linux-os.c
+++ b/src/runtime/linux-os.c
@@ -84,7 +84,18 @@ static inline int sys_futex (void *futex, int op, int val, struct timespec *rel)
 int
 futex_wait(int *lock_word, int oldval)
 {
-    int t= sys_futex(lock_word,FUTEX_WAIT,oldval, 0);
+    int t;
+  again:
+    t = sys_futex(lock_word,FUTEX_WAIT,oldval, 0);
+
+    /* Interrupted FUTEX_WAIT calls may return early.
+     *
+     * If someone manages to wake the futex while we're spinning
+     * around it, we will just return with -1 and errno EWOULDBLOCK,
+     * because the value has changed, so that's ok. */
+    if (t != 0 && errno == EINTR)
+        goto again;
+
     return t;
 }
 
@@ -98,6 +109,21 @@ futex_wake(int *lock_word, int n)
 \f
 int linux_sparc_siginfo_bug = 0;
 
+/* This variable was in real use for a few months, basically for
+ * storing autodetected information about whether the Linux
+ * installation was recent enough to support SBCL threads, and make
+ * some run-time decisions based on that. But this turned out to be
+ * unstable, so now we just flat-out refuse to start on the old installations
+ * when thread support has been compiled in.
+ *
+ * Unfortunately, in the meanwhile Slime started depending on this
+ * variable for deciding which communication style to use. So even
+ * though this variable looks unused, it shouldn't be deleted until
+ * it's no longer used in the versions of Slime that people are
+ * likely to download first. -- JES, 2006-06-07
+ */
+int linux_no_threads_p = 0;
+
 #ifdef LISP_FEATURE_SB_THREAD
 int
 isnptl (void)