Commit a73f863a authored by Juri Lelli's avatar Juri Lelli Committed by Ingo Molnar
Browse files

sched/features: Fix !CONFIG_JUMP_LABEL case 



Commit:

  765cc3a4 ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds")

made sched features static for !CONFIG_SCHED_DEBUG configurations, but
overlooked the CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL cases.

For the latter echoing changes to /sys/kernel/debug/sched_features has
the nasty effect of effectively changing what sched_features reports,
but without actually changing the scheduler behaviour (since different
translation units get different sysctl_sched_features).

Fix CONFIG_SCHED_DEBUG=y and !CONFIG_JUMP_LABEL configurations by properly
restructuring ifdefs.

Fixes: 765cc3a4 ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds")
Co-developed-by: default avatarDaniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: default avatarDaniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: default avatarJuri Lelli <juri.lelli@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarPatrick Bellasi <patrick.bellasi@matbug.net>
Reviewed-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20201013053114.160628-1-juri.lelli@redhat.com
parent eba9f082

kernel/sched/core.c

+1 −1
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp); 


DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);



#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL)

#ifdef CONFIG_SCHED_DEBUG

/*

 * Debugging: various feature bits

 *

kernel/sched/sched.h

+10 −3
Original line number Diff line number Diff line
@@ -1629,7 +1629,7 @@ enum { 


#undef SCHED_FEAT



#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_JUMP_LABEL)

#ifdef CONFIG_SCHED_DEBUG



/*

 * To support run-time toggling of sched features, all the translation units
@@ -1637,6 +1637,7 @@ enum { 
 */

extern const_debug unsigned int sysctl_sched_features;



#ifdef CONFIG_JUMP_LABEL

#define SCHED_FEAT(name, enabled)					\

static __always_inline bool static_branch_##name(struct static_key *key) \

{									\
@@ -1649,7 +1650,13 @@ static __always_inline bool static_branch_##name(struct static_key *key) \ 
extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];

#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))



#else /* !(SCHED_DEBUG && CONFIG_JUMP_LABEL) */

#else /* !CONFIG_JUMP_LABEL */



#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))



#endif /* CONFIG_JUMP_LABEL */



#else /* !SCHED_DEBUG */



/*

 * Each translation unit has its own copy of sysctl_sched_features to allow
@@ -1665,7 +1672,7 @@ static const_debug __maybe_unused unsigned int sysctl_sched_features = 


#define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x))



#endif /* SCHED_DEBUG && CONFIG_JUMP_LABEL */

#endif /* SCHED_DEBUG */



extern struct static_key_false sched_numa_balancing;

extern struct static_key_false sched_schedstats;

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