On 2014-05-27 17:21, Gedare Bloom wrote:
On Tue, May 27, 2014 at 10:48 AM, Ralf Kirchner
<ralf.kirch...@embedded-brains.de> wrote:
>Enabling and disabling preemption as done for single core will not work for
SMP.
>Thus as a temporary workaround use POSIX mutexes and POSIX condition variables
for SMP instead of the combination of semaphores and preemption handling used for
single core.
>---
> cpukit/libblock/src/bdbuf.c | 348
+++++++++++++++++++++++++++++++++++--------
> 1 Datei geändert, 282 Zeilen hinzugefügt(+), 66 Zeilen entfernt(-)
>
>diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
>index 1e4887c..0caf8f5 100644
>--- a/cpukit/libblock/src/bdbuf.c
>+++ b/cpukit/libblock/src/bdbuf.c
>@@ -43,6 +43,23 @@
>
> #include "rtems/bdbuf.h"
>
>+#if defined( RTEMS_SMP )
>+ #if defined( RTEMS_POSIX_API )
>+ /* The single core implementation with enabling and disabling preemption
>+ * will not work under SMP. Thus we need to use POSIX mutexes and POSIX
>+ * condition variables as a workaround
>+ * Required POSIX mutexes and POSIX condition variables will be allocated
>+ * automatically in confdefs.h if RTEMS_SMP and RTEMS_POSIX_API
>+ * are #defined
>+ */
>+ #define RTEMS_BDBUF_SMP_WORKAROUND
Workaround implies a temporary solution. Is there a longer-term
solution in the works? Otherwise, we should just condition this on
RTEMS_SMP?
We need condition variables in the Classic API.
What if RTEMS_SMP is defined, but RTEMS_POSIX_API is not? This would
be an error here I suppose? Or possibly elsewhere in the bdbuf
workaround code? Probably it should be accounted in confdefs.h and an
error emitted?
RTEMS_SMP without RTEMS_POSIX_API falls back to the current situation. You get
a fatal error at run-time. A compile-time error is bad, since this would break
the test suite build.
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
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