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Message-ID: <A46BBDB345A7D5118EC90002A5072C780B7177A5@orsmsx116.jf.intel.com>
From: "Perez-Gonzalez, Inaky" <inaky.perez-gonzalez@intel.com>
To: "'lkml (linux-kernel@vger.kernel.org)'" 
	<linux-kernel@vger.kernel.org>,
       "'Ingo Molnar (mingo@redhat.com)'" <mingo@redhat.com>
Subject: migration_thread()'s priority too low?
Date: Fri, 28 Mar 2003 20:50:32 -0800
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Hi all, Ingo

I am having some trouble in the priority-inheritance wakeup code when
using FIFO tasks - I was wondering: migration_thread() has the equivalent of
a FIFO priority 0; thus, it will be left out by any FIFO task and migration
won't work - I don't think this is causing the problem to my test cases, but
I was curious anyway.

Setting it in 2.5.66's sched.c like this

@@ -2436,7 +2435,7 @@
  */
 static int migration_thread(void * data)
 {
-	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+	struct sched_param param = { .sched_priority = 0 };
 	int cpu = (long) data;
 	runqueue_t *rq;
 	int ret;

gives it max priority; it'd be interesting though to have an extra level so
have FIFO 99 be 1 in the index and 0 still be free for system stuff.

Of course I can be missing anything really clear. Is it intentionate that
migration_thread() has FIFO 0?

I?aky P?rez-Gonz?lez -- Not speaking for Intel -- all opinions are my own
(and my fault)
-
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