[PATCH] schedstat: UP fix

SMP fix --
    for_each_domain() is not defined if not CONFIG_SMP, so show_schedstat
    needed a couple of extra ifdefs.
Signed-off-by: Rick Lindsley <ricklind@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/sched-stats.txt

 Version 10 of schedstats includes support for sched_domains, which
 hit the mainline kernel in 2.6.7.  Some counters make more sense to be
-per-runqueue; other to be per-domain.
+per-runqueue; other to be per-domain.  Note that domains (and their associated
+information) will only be pertinent and available on machines utilizing
+CONFIG_SMP.
 
 In version 10 of schedstat, there is at least one level of domain
 statistics for each cpu listed, and there may well be more than one
@@ -83,7 +85,9 @@ The last six are statistics dealing with pull_task():
 
 Domain statistics
 -----------------
-One of these is produced per domain for each cpu described.
+One of these is produced per domain for each cpu described. (Note that if
+CONFIG_SMP is not defined, *no* domains are utilized and these lines
+will not appear in the output.)
 
 domain<N> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
 

kernel/sched.c

@@ -483,8 +483,10 @@ static int show_schedstat(struct seq_file *seq, void *v)
 	seq_printf(seq, "timestamp %lu\n", jiffies);
 	for_each_online_cpu(cpu) {
 		runqueue_t *rq = cpu_rq(cpu);
+#ifdef CONFIG_SMP
 		struct sched_domain *sd;
 		int dcnt = 0;
+#endif
 
 		/* runqueue-specific stats */
 		seq_printf(seq,
@@ -506,6 +508,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 						    rq->pt_lost[itype]);
 		seq_printf(seq, "\n");
 
+#ifdef CONFIG_SMP
 		/* domain-specific stats */
 		for_each_domain(cpu, sd) {
 			char mask_str[NR_CPUS];
@@ -524,6 +527,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 			    sd->sbe_pushed, sd->sbe_attempts,
 			    sd->ttwu_wake_affine, sd->ttwu_wake_balance);
 		}
+#endif
 	}
 	return 0;
 }