[Devel] [PATCH vz10 04/32] sched/cpuacct: guard ve_root_tg() with CONFIG_CFS_CPULIMIT

[Konstantin Khorenko]

ve_root_tg() has exactly two callers, tg_cpu_rate() and tg_nr_cpus(),
and both reference it only from inside #ifdef CONFIG_CFS_CPULIMIT: the
task_group fields they read, ::cpu_rate and ::nr_cpus, do not exist
without that option.  So with CONFIG_CFS_CPULIMIT=n the helper is not
used at all.  x86_64 defconfig is exactly that configuration - CONFIG_VE
defaults to y while CONFIG_CFS_BANDWIDTH, the only thing that selects
CONFIG_CFS_CPULIMIT, is off - and it sets CONFIG_WERROR=y as well, so
there the unused function is not a warning but a build failure:

  kernel/sched/cpuacct.c:373:27: error: 've_root_tg' defined but not
                                 used [-Werror=unused-function]

Compile ve_root_tg() under the same condition as its call sites.

Fixes: 095994c57b84 ("ve/sched/stat: Introduce functions to calculate vcpustat data")
Feature: sched: emulate virtual cpus for Containers
https://virtuozzo.atlassian.net/browse/VSTOR-134732
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 kernel/sched/cpuacct.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 01a2b2c3c5b7..6b0ed967316e 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -370,6 +370,7 @@ struct cgroup_subsys cpuacct_cgrp_subsys = {
 	.threaded       = true,
 };
 
+#ifdef CONFIG_CFS_CPULIMIT
 static struct task_group *ve_root_tg(struct task_group *tg) {
 	struct cgroup_subsys_state *css;
 
@@ -379,6 +380,7 @@ static struct task_group *ve_root_tg(struct task_group *tg) {
 	css = css_ve_root1(&tg->css);
 	return css ? css_tg(css) : NULL;
 }
+#endif
 
 static unsigned int tg_cpu_rate(struct task_group *tg)
 {
-- 
2.47.1