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sched/features: Fix !CONFIG_JUMP_LABEL case

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[ Upstream commit a73f863af4ce9730795eab7097fb2102e6854365 ]

Commit:

  765cc3a4b2 ("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: 765cc3a4b2 ("sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds")
Co-developed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Patrick Bellasi <patrick.bellasi@matbug.net>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20201013053114.160628-1-juri.lelli@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Juri Lelli 2020-10-13 07:31:14 +02:00 committed by Greg Kroah-Hartman
parent 2d1fba2112
commit 2e2f41a960
2 changed files with 11 additions and 4 deletions
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2
kernel/sched/core.c
View file

@ -24,7 +24,7 @@
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
*

13
kernel/sched/sched.h
View file

@ -1361,7 +1361,7 @@ 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
@ -1369,6 +1369,7 @@ 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) \
{ \
@ -1381,7 +1382,13 @@ 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
@ -1397,7 +1404,7 @@ 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;