sched: Remove sched_switch

Currently we don't utilize the sched_switch field anymore.

But, simply removing sched_switch field from the middle of the
sched_stat output will break tools.

So, to stay compatible we hardcode it to zero and remove the
field from the scheduler data structures.

Update the schedstat documentation accordingly.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1327422836.27181.5.camel@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 4 insertions, 5 deletions

diff --git a/Documentation/scheduler/sched-stats.txt b/Documentation/scheduler/sched-stats.txt
index 1cd5d51bc761..8259b34a66ae 100644
--- a/Documentation/scheduler/sched-stats.txt
+++ b/Documentation/scheduler/sched-stats.txt
@@ -38,7 +38,8 @@ First field is a sched_yield() statistic:
      1) # of times sched_yield() was called
 
 Next three are schedule() statistics:
-     2) # of times we switched to the expired queue and reused it
+     2) This field is a legacy array expiration count field used in the O(1)
+        scheduler. We kept it for ABI compatibility, but it is always set to zero.
      3) # of times schedule() was called
      4) # of times schedule() left the processor idle
 
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2a075e10004b..09acaa15161d 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -288,7 +288,6 @@ static void print_cpu(struct seq_file *m, int cpu)
 
         P(yld_count);
 
-        P(sched_switch);
         P(sched_count);
         P(sched_goidle);
 #ifdef CONFIG_SMP
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 98c0c2623db8..8a2c768d2f98 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -462,7 +462,6 @@ struct rq {
         unsigned int yld_count;
 
         /* schedule() stats */
-        unsigned int sched_switch;
         unsigned int sched_count;
         unsigned int sched_goidle;
 
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 2a581ba8e190..903ffa9e8872 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -32,9 +32,9 @@ static int show_schedstat(struct seq_file *seq, void *v)
 
                 /* runqueue-specific stats */
                 seq_printf(seq,
-                    "cpu%d %u %u %u %u %u %u %llu %llu %lu",
+                    "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
                     cpu, rq->yld_count,
-                    rq->sched_switch, rq->sched_count, rq->sched_goidle,
+                    rq->sched_count, rq->sched_goidle,
                     rq->ttwu_count, rq->ttwu_local,
                     rq->rq_cpu_time,
                     rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);