Martin Schwidefsky wrote:
On Fri, 2006-04-28 at 10:39 +0200, Heiko Carstens wrote:
+++ linux-2.6-patched/drivers/s390/s390mach.c 2006-04-24 16:47:28.000000000 +0200
...
+#define MAX_IPD_TIME (5 * 60 * 100 * 1000) /* 5 minutes */
^^^^^^^^^^^^^^^^^^^^
Expression A
I'm no s390 expert, but shouldn't the above use something like HZ?
Using HZ here feels just wrong to me. MAX_IPD_TIME has nothing to do with the
timer frequency. In this case it's used to tell if there were 30 machine
checks within the last 5 minutes (in a usec granularity). It's just by
accident that this could be expressed using HZ.
(5 * 60 * USEC_PER_SEC) would probably look better...
^^^^^^^^^^^^^^^^^^^^^^^
Expression B
I'm no s390 expert either, but just wanted to point out that expression
B is 10 times larger than expression A, so something's fishy here.
Using HZ would be wrong. The check that uses MAX_IPD_TIME compares it
against the result of a get_clock() call. That uses the TOD Clock
directly, there is no dependency on HZ.
Looking at include/asm-s390/timex.h:
#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
makes me wonder if this should be:
#define MAX_IPD_TIME (5 * 60 * CLOCK_TICK_RATE) /* 5 minutes */
--
Paulo Marques - www.grupopie.com
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