| From | Willy Tarreau <> | Subject | [PATCH 3.10 171/250] locking/static_keys: Add static_key_{en,dis}able() helpers | Date | Thu, 8 Jun 2017 00:59:17 +0200 |
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From: Peter Zijlstra <peterz@infradead.org>
commit e33886b38cc82a9fc3b2d655dfc7f50467594138 upstream.
Add two helpers to make it easier to treat the refcount as boolean.
[js] do not involve WARN_ON_ONCE as it causes build failures
Suggested-by: Jason Baron <jasonbaron0@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> [wt: only backported for use in next fix ; s/static_key_count(key)/atomic_read(&key->enabled)/]
Signed-off-by: Willy Tarreau <w@1wt.eu> --- include/linux/jump_label.h | 16 ++++++++++++++++ kernel/sched/core.c | 6 ++---- 2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 0976fc4..7f831b2 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -208,4 +208,20 @@ static inline bool static_key_enabled(struct static_key *key) return (atomic_read(&key->enabled) > 0); } +static inline void static_key_enable(struct static_key *key) +{ + int count = atomic_read(&key->enabled); + + if (!count) + static_key_slow_inc(key); +} + +static inline void static_key_disable(struct static_key *key) +{ + int count = atomic_read(&key->enabled); + + if (count) + static_key_slow_dec(key); +} + #endif /* _LINUX_JUMP_LABEL_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6a366f9..506e56e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -179,14 +179,12 @@ struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { static void sched_feat_disable(int i) { - if (static_key_enabled(&sched_feat_keys[i])) - static_key_slow_dec(&sched_feat_keys[i]); + static_key_disable(&sched_feat_keys[i]); } static void sched_feat_enable(int i) { - if (!static_key_enabled(&sched_feat_keys[i])) - static_key_slow_inc(&sched_feat_keys[i]); + static_key_enable(&sched_feat_keys[i]); } #else static void sched_feat_disable(int i) { }; -- 2.8.0.rc2.1.gbe9624a
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