On Tue, Sep 17, 2019 at 08:52:42 +0100, Ingo Molnar wrote...
> * Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
>> On 9/16/19 3:38 PM, Mark Brown wrote:
>> > Hi all,
>> >
>> > Changes since 20190915:
>> >
>>
>> on x86_64:
>>
>> when CONFIG_CGROUPS is not set:
Hi Randy,
thanks for the report.
>> CC kernel/sched/core.o
>> ../kernel/sched/core.c: In function ‘uclamp_update_active_tasks’:
>> ../kernel/sched/core.c:1081:23: error: storage size of ‘it’ isn’t known
>> struct css_task_iter it;
>> ^~
>> CC kernel/printk/printk_safe.o
>> ../kernel/sched/core.c:1084:2: error: implicit declaration of function ‘css_task_iter_start’; did you mean ‘__sg_page_iter_start’? [-Werror=implicit-function-declaration]
>> css_task_iter_start(css, 0, &it);
>> ^~~~~~~~~~~~~~~~~~~
>> __sg_page_iter_start
>> ../kernel/sched/core.c:1085:14: error: implicit declaration of function ‘css_task_iter_next’; did you mean ‘__sg_page_iter_next’? [-Werror=implicit-function-declaration]
>> while ((p = css_task_iter_next(&it))) {
>> ^~~~~~~~~~~~~~~~~~
>> __sg_page_iter_next
>> ../kernel/sched/core.c:1091:2: error: implicit declaration of function ‘css_task_iter_end’; did you mean ‘get_task_cred’? [-Werror=implicit-function-declaration]
>> css_task_iter_end(&it);
>> ^~~~~~~~~~~~~~~~~
>> get_task_cred
>> ../kernel/sched/core.c:1081:23: warning: unused variable ‘it’ [-Wunused-variable]
>> struct css_task_iter it;
>> ^~
>>
>
> I cannot reproduce this build failue: I took Linus's latest which has all
> the -next scheduler commits included (ad062195731b), and an x86-64 "make
> defconfig" and a disabling of CONFIG_CGROUPS still resuls in a kernel
> that builds fine.
Same here Ingo, I cannot reproduce on arm64 and !CONFIG_CGROUPS and
testing on tip/sched/core.
However, if you like, the following patch can make that code a
bit more "robust".
Best,
Patrick
---8<---
>From 7e17b7bb08dd8dfc57e01c2a7b6875439eb47cbe Mon Sep 17 00:00:00 2001
From: Patrick Bellasi <patrick.bellasi@xxxxxxx>
Date: Tue, 17 Sep 2019 14:12:10 +0100
Subject: [PATCH 1/1] sched/core: uclamp: Fix compile error on !CONFIG_CGROUPS
Randy reported a compiler error on x86_64 and !CONFIG_CGROUPS which is due
to uclamp_update_active_tasks() using the undefined css_task_iter().
Since uclamp_update_active_tasks() is used only when cgroup support is
enabled, fix that by properly guarding that function at compile time.
Signed-off-by: Patrick Bellasi <patrick.bellasi@xxxxxxx>
Link: https://lore.kernel.org/lkml/1898d3c9-1997-17ce-a022-a5e28c8dc115@xxxxxxxxxxxxx/
Fixes: commit babbe170e05 ("sched/uclamp: Update CPU's refcount on TG's clamp changes")
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3c7b90bcbe4e..14873ad4b34a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1043,6 +1043,7 @@ static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p)
uclamp_rq_dec_id(rq, p, clamp_id);
}
+#ifdef CONFIG_UCLAMP_TASK_GROUP
static inline void
uclamp_update_active(struct task_struct *p, enum uclamp_id clamp_id)
{
@@ -1091,7 +1092,6 @@ uclamp_update_active_tasks(struct cgroup_subsys_state *css,
css_task_iter_end(&it);
}
-#ifdef CONFIG_UCLAMP_TASK_GROUP
static void cpu_util_update_eff(struct cgroup_subsys_state *css);
static void uclamp_update_root_tg(void)
{
--
2.22.0
---8<---
--
#include <best/regards.h>
Patrick Bellasi
