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Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h17
1 files changed, 12 insertions, 5 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e5b8cbc4b8d6..23ca455d9582 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -599,11 +599,7 @@ struct task_cputime_atomic {
.sum_exec_runtime = ATOMIC64_INIT(0), \
}
-#ifdef CONFIG_PREEMPT_COUNT
-#define PREEMPT_DISABLED (1 + PREEMPT_ENABLED)
-#else
-#define PREEMPT_DISABLED PREEMPT_ENABLED
-#endif
+#define PREEMPT_DISABLED (PREEMPT_DISABLE_OFFSET + PREEMPT_ENABLED)
/*
* Disable preemption until the scheduler is running -- use an unconditional
@@ -613,6 +609,17 @@ struct task_cputime_atomic {
*/
#define INIT_PREEMPT_COUNT PREEMPT_OFFSET
+/*
+ * Initial preempt_count value; reflects the preempt_count schedule invariant
+ * which states that during context switches:
+ *
+ * preempt_count() == 2*PREEMPT_DISABLE_OFFSET
+ *
+ * Note: PREEMPT_DISABLE_OFFSET is 0 for !PREEMPT_COUNT kernels.
+ * Note: See finish_task_switch().
+ */
+#define FORK_PREEMPT_COUNT (2*PREEMPT_DISABLE_OFFSET + PREEMPT_ENABLED)
+
/**
* struct thread_group_cputimer - thread group interval timer counts
* @cputime_atomic: atomic thread group interval timers.