[Devel] [PATCH vz10 01/14] sched: fix VZ build errors with CONFIG_CGROUP_SCHED=n

[Eva Kurchatova]

Guard VZ-specific code that depends on struct task_group,
root_task_group, cpu_cgrp_id and cpuacct_cgrp_id with the appropriate
Kconfig options.

Without CONFIG_CGROUP_SCHED:
- struct task_group is incomplete, so get_avenrun_tg() and
  calc_load_ve() fail to compile.
- cpu_cgrp_id is undeclared, so the link_ve_root_cpu_cgroup() call in
  cgroup_mark_ve_roots() does not build.

Without CONFIG_CGROUP_CPUACCT:
- cpuacct_cgrp_id is undeclared, so the cpu_cgrp_subsys.depends_on
  initializer fails.
- cpu_cgroup_update_vcpustat() uses MAX_CPU_RATE which requires
  CONFIG_CFS_CPULIMIT.

Add a static inline stub for get_avenrun_tg() when CONFIG_CGROUP_SCHED
is disabled, tighten the guards on calc_load_ve() to require both
CONFIG_VE and CONFIG_CGROUP_SCHED, and wrap cpu_cgroup_update_vcpustat()
with CONFIG_CFS_CPULIMIT.

Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>

https://virtuozzo.atlassian.net/browse/VSTOR-134732
Feature: fix kunit
---
 include/linux/sched/loadavg.h | 10 +++++++++-
 kernel/sched/core.c           |  2 ++
 kernel/sched/cpuacct.c        |  5 +++++
 kernel/sched/loadavg.c        |  6 ++++--
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/include/linux/sched/loadavg.h b/include/linux/sched/loadavg.h
index 771e753e4670..f019a7306600 100644
--- a/include/linux/sched/loadavg.h
+++ b/include/linux/sched/loadavg.h
@@ -18,8 +18,16 @@ extern unsigned long avenrun[];		/* Load averages */
 extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
 
 struct task_group;
+#ifdef CONFIG_CGROUP_SCHED
 extern int get_avenrun_tg(struct task_group *tg, unsigned long *loads,
 			  unsigned long offset, int shift);
+#else
+static inline int get_avenrun_tg(struct task_group *tg, unsigned long *loads,
+				 unsigned long offset, int shift)
+{
+	return -1;
+}
+#endif
 
 #define FSHIFT		11		/* nr of bits of precision */
 #define FIXED_1		(1<<FSHIFT)	/* 1.0 as fixed-point */
@@ -51,7 +59,7 @@ extern unsigned long calc_load_n(unsigned long load, unsigned long exp,
 
 extern bool calc_global_load(void);
 
-#ifdef CONFIG_VE
+#if defined(CONFIG_VE) && defined(CONFIG_CGROUP_SCHED)
 extern void calc_load_ve(void);
 #else
 #define calc_load_ve() do { } while (0)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d5b4d8c97a0c..7d2214749245 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10441,7 +10441,9 @@ struct cgroup_subsys cpu_cgrp_subsys = {
 	.dfl_cftypes	= cpu_files,
 	.early_init	= true,
 	.threaded	= true,
+#ifdef CONFIG_CGROUP_CPUACCT
 	.depends_on	= 1 << cpuacct_cgrp_id,
+#endif
 };
 
 #endif /* CONFIG_CGROUP_SCHED */
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 01a2b2c3c5b7..98c13ff2bac8 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -542,6 +542,7 @@ static void fixup_vcpustat_delta(struct kernel_cpustat *cur,
 	cur->cpustat[CPUTIME_STEAL] = 0;
 }
 
+#ifdef CONFIG_CFS_CPULIMIT
 static void cpu_cgroup_update_vcpustat(struct cgroup_subsys_state *cpu_css,
 				       struct cgroup_subsys_state *cpuacct_css)
 {
@@ -632,6 +633,10 @@ static void cpu_cgroup_update_vcpustat(struct cgroup_subsys_state *cpu_css,
 out_unlock:
 	spin_unlock(&tg->vcpustat_lock);
 }
+#else
+static inline void cpu_cgroup_update_vcpustat(struct cgroup_subsys_state *cpu_css,
+					      struct cgroup_subsys_state *cpuacct_css) {}
+#endif
 
 int cpu_cgroup_proc_stat(struct cgroup_subsys_state *cpu_css,
 			 struct cgroup_subsys_state *cpuacct_css,
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index bc0b6bcdae2d..c4ca3c83f1cf 100644
--- a/kernel/sched/loadavg.c
+++ b/kernel/sched/loadavg.c
@@ -78,6 +78,7 @@ void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
 	loads[2] = (avenrun[2] + offset) << shift;
 }
 
+#ifdef CONFIG_CGROUP_SCHED
 int get_avenrun_tg(struct task_group *tg, unsigned long *loads,
 		   unsigned long offset, int shift)
 {
@@ -93,6 +94,7 @@ int get_avenrun_tg(struct task_group *tg, unsigned long *loads,
 
 	return 0;
 }
+#endif
 
 long calc_load_fold_active(struct rq *this_rq, long adjust)
 {
@@ -109,7 +111,7 @@ long calc_load_fold_active(struct rq *this_rq, long adjust)
 	return delta;
 }
 
-#ifdef CONFIG_VE
+#if defined(CONFIG_VE) && defined(CONFIG_CGROUP_SCHED)
 extern struct list_head ve_root_list;
 extern raw_spinlock_t load_ve_lock;
 
@@ -166,7 +168,7 @@ void calc_load_ve(void)
 	kstat_glob.nr_unint_avg[2] = calc_load(kstat_glob.nr_unint_avg[2], EXP_15, nr_unint);
 	write_seqcount_end(&kstat_glob.nr_unint_avg_seq);
 }
-#endif /* CONFIG_VE */
+#endif /* CONFIG_VE && CONFIG_CGROUP_SCHED */
 
 /**
  * fixed_power_int - compute: x^n, in O(log n) time
-- 
2.54.0