From a9903f04e0a4ea522d959c2f287cdf0ab029e324 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Mon, 30 Oct 2017 11:08:16 -0700 Subject: [PATCH] sched/sysctl: Fix attributes of some extern declarations 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 Reviewed-by: Nick Desaulniers Cc: Douglas Anderson Cc: Guenter Roeck Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shile Zhang Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20171030180816.170850-1-mka@chromium.org Signed-off-by: Ingo Molnar --- include/linux/sched/sysctl.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 0f5ecd4d298e..d34c823f3d36 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -37,9 +37,9 @@ extern unsigned int sysctl_numa_balancing_scan_period_max; 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; int sched_proc_update_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, -- 2.20.1