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| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-01-06 11:45:07 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-01-14 15:07:32 +0100 |
| commit | d84b6728c54dcf73bcef3e3f7cf6767e2d224e39 (patch) | |
| tree | c3d8f60aee0a71f79666e3d47df73deff975a5ab /include/linux/osq_lock.h | |
| parent | 4bd19084faa61a8c68586e74f03f5776179f65c2 (diff) | |
| download | lwn-d84b6728c54dcf73bcef3e3f7cf6767e2d224e39.tar.gz lwn-d84b6728c54dcf73bcef3e3f7cf6767e2d224e39.zip | |
locking/mcs: Better differentiate between MCS variants
We have two flavors of the MCS spinlock: standard and cancelable (OSQ).
While each one is independent of the other, we currently mix and match
them. This patch:
- Moves the OSQ code out of mcs_spinlock.h (which only deals with the traditional
version) into include/linux/osq_lock.h. No unnecessary code is added to the
more global header file, anything locks that make use of OSQ must include
it anyway.
- Renames mcs_spinlock.c to osq_lock.c. This file only contains osq code.
- Introduces a CONFIG_LOCK_SPIN_ON_OWNER in order to only build osq_lock
if there is support for it.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1420573509-24774-5-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/osq_lock.h')
| -rw-r--r-- | include/linux/osq_lock.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/osq_lock.h b/include/linux/osq_lock.h index 90230d5811c5..3a6490e81b28 100644 --- a/include/linux/osq_lock.h +++ b/include/linux/osq_lock.h @@ -5,8 +5,11 @@ * An MCS like lock especially tailored for optimistic spinning for sleeping * lock implementations (mutex, rwsem, etc). */ - -#define OSQ_UNLOCKED_VAL (0) +struct optimistic_spin_node { + struct optimistic_spin_node *next, *prev; + int locked; /* 1 if lock acquired */ + int cpu; /* encoded CPU # + 1 value */ +}; struct optimistic_spin_queue { /* @@ -16,6 +19,8 @@ struct optimistic_spin_queue { atomic_t tail; }; +#define OSQ_UNLOCKED_VAL (0) + /* Init macro and function. */ #define OSQ_LOCK_UNLOCKED { ATOMIC_INIT(OSQ_UNLOCKED_VAL) } @@ -24,4 +29,7 @@ static inline void osq_lock_init(struct optimistic_spin_queue *lock) atomic_set(&lock->tail, OSQ_UNLOCKED_VAL); } +extern bool osq_lock(struct optimistic_spin_queue *lock); +extern void osq_unlock(struct optimistic_spin_queue *lock); + #endif |