4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
commit a9903f04e0a4ea522d959c2f287cdf0ab029e324 upstream.
The definition of sysctl_sched_migration_cost, sysctl_sched_nr_migrate
and sysctl_sched_time_avg includes the attribute const_debug. This
attribute is not part of the extern declaration of these variables in
include/linux/sched/sysctl.h, while it is in kernel/sched/sched.h,
and as a result Clang generates warnings like this:
kernel/sched/sched.h:1618:33: warning: section attribute is specified on redeclared variable [-Wsection]
extern const_debug unsigned int sysctl_sched_time_avg;
^
./include/linux/sched/sysctl.h:42:21: note: previous declaration is here
extern unsigned int sysctl_sched_time_avg;
The header only declares the variables when CONFIG_SCHED_DEBUG is defined,
therefore it is not necessary to duplicate the definition of const_debug.
Instead we can use the attribute __read_mostly, which is the expansion of
const_debug when CONFIG_SCHED_DEBUG=y is set.
Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Reviewed-by: Nick Desaulniers <nick.desaulniers@xxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Guenter Roeck <groeck@xxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Shile Zhang <shile.zhang@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171030180816.170850-1-mka@xxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
[nc: Backport to 4.9]
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/sched/sysctl.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -33,9 +33,9 @@ extern unsigned int sysctl_numa_balancin
extern unsigned int sysctl_numa_balancing_scan_size;
#ifdef CONFIG_SCHED_DEBUG
-extern unsigned int sysctl_sched_migration_cost;
-extern unsigned int sysctl_sched_nr_migrate;
-extern unsigned int sysctl_sched_time_avg;
+extern __read_mostly unsigned int sysctl_sched_migration_cost;
+extern __read_mostly unsigned int sysctl_sched_nr_migrate;
+extern __read_mostly unsigned int sysctl_sched_time_avg;
extern unsigned int sysctl_sched_shares_window;
int sched_proc_update_handler(struct ctl_table *table, int write,
