Allow preemptive-spinning configuration.

1 files changed, 7 insertions, 1 deletions

diff --git a/include/config.h b/include/config.h
index c5e38a2..af41d42 100644
--- a/include/config.h
+++ b/include/config.h
@@ -12,6 +12,10 @@
  */
 #ifndef _USE_LITMUS
         #define PGM_SYNC_METHOD         0
+/* You must define PGM_ALLOW_P_SPIN if
+   preemptions remain enabled.
+ */
+/*      #define PGM_SYNC_METHOD         1 */
 #else
         /* Default to PGM spinlocks under Litmus */
         #define PGM_SYNC_METHOD         1
@@ -32,6 +36,8 @@
  */
 #ifndef _USE_LITMUS
         #define PGM_NP_METHOD           0
+/* Uncomment to allow preemptive spinning sync */
+/*      #define PGM_ALLOW_P_SPIN */
 #else
         /* Default to Litmus NP sections. */
         #define PGM_NP_METHOD           2
@@ -54,7 +60,7 @@
 #error "Cannot disable interrupts using pthread synchronization."
 #endif
 
-#if (PGM_SYNC_METHOD == 1) && (PGM_NP_METHOD == 0)
+#if (PGM_SYNC_METHOD == 1) && (PGM_NP_METHOD == 0) && !defined(PGM_ALLOW_P_SPIN)
 #error "Spinlocks are unsafe without non-preemption."
 #endif