2 messages, 2 authors, 2002-05-21 · open the first message on its own page
From: <hidden>
Date: 2002-05-21 12:47:40
Hello!
I understand the issue.
I do not.
+#define preempt_disable() \
+do { \
+ ++current->preempt_count; \
+ barrier(); \
+} while (0)
Why does this work?
Alexey
From: george anzinger <hidden>
Date: 2002-05-21 15:42:51
kuznet@ms2.inr.ac.ru wrote:
Hello!quoted
I understand the issue.I do not. +#define preempt_disable() \ +do { \ + ++current->preempt_count; \ + barrier(); \ +} while (0) Why does this work? Alexey
Preemption can only happen if the task is interrupted. The interrupt exit code will not preempt if preempt_count is more than zero. The barrier() forces the result to memory so the interrupt code can find it. -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml