Commit-ID: ade9862470dd0595d8e292ecea8445ed90b98df5
Gitweb: http://git.kernel.org/tip/ade9862470dd0595d8e292ecea8445ed90b98df5
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 31 Jul 2014 16:02:33 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 7 Sep 2014 16:18:18 -0700
rcu: Make TINY_RCU tinier by putting error checks under #ifdef
The rcu_idle_enter_common() and rcu_idle_exit_common() functions contain
error checks that have to the best of my knowledge have never triggered
over the past several years. These are nevertheless valuable when
creating new architectures or doing other low-level changes, so the
checks should not be deleted. This commit instead places these checks
under #ifdef CONFIG_RCU_TRACE so that they are executed only when
specifically requested.
The savings are significant:
Before:
text data bss dec hex filename
1749 39 0 1788 6fc /tmp/b/kernel/rcu/tiny.o
632 152 0 784 310 /tmp/b/kernel/rcu/update.o
----
2572
After:
text data bss dec hex filename
1281 37 0 1318 526 /tmp/b/kernel/rcu/tiny.o
632 152 0 784 310 /tmp/b/kernel/rcu/update.o
----
2102
This amounts to 470 bytes, or 18% of the original.
Switched from #ifdef to IS_ENABLED() on Josh Triplett's advice.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcu/tiny.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 6bd785c..4a55a24 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -62,7 +62,7 @@ static void rcu_idle_enter_common(long long newval)
}
RCU_TRACE(trace_rcu_dyntick(TPS("Start"),
rcu_dynticks_nesting, newval));
- if (!is_idle_task(current)) {
+ if (IS_ENABLED(CONFIG_RCU_TRACE) && !is_idle_task(current)) {
struct task_struct *idle __maybe_unused = idle_task(smp_processor_id());
RCU_TRACE(trace_rcu_dyntick(TPS("Entry error: not idle task"),
@@ -123,7 +123,7 @@ static void rcu_idle_exit_common(long long oldval)
return;
}
RCU_TRACE(trace_rcu_dyntick(TPS("End"), oldval, rcu_dynticks_nesting));
- if (!is_idle_task(current)) {
+ if (IS_ENABLED(CONFIG_RCU_TRACE) && !is_idle_task(current)) {
struct task_struct *idle __maybe_unused = idle_task(smp_processor_id());
RCU_TRACE(trace_rcu_dyntick(TPS("Exit error: not idle task"),
--
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