diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2014-01-29 12:51:42 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2014-03-11 12:14:56 +0100 |
| commit | fb0527bd5ea99bfeb2dd91e3c1433ecf745d6b99 (patch) | |
| tree | b3ab4c067c035688d4295fdcadf00170465db7df /kernel/locking/mcs_spinlock.h | |
| parent | locking/mutexes: Unlock the mutex without the wait_lock (diff) | |
| download | wireguard-linux-fb0527bd5ea99bfeb2dd91e3c1433ecf745d6b99.tar.xz wireguard-linux-fb0527bd5ea99bfeb2dd91e3c1433ecf745d6b99.zip | |
locking/mutexes: Introduce cancelable MCS lock for adaptive spinning
Since we want a task waiting for a mutex_lock() to go to sleep and
reschedule on need_resched() we must be able to abort the
mcs_spin_lock() around the adaptive spin.
Therefore implement a cancelable mcs lock.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: chegu_vinod@hp.com
Cc: paulmck@linux.vnet.ibm.com
Cc: Waiman.Long@hp.com
Cc: torvalds@linux-foundation.org
Cc: tglx@linutronix.de
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
Cc: davidlohr@hp.com
Cc: hpa@zytor.com
Cc: andi@firstfloor.org
Cc: aswin@hp.com
Cc: scott.norton@hp.com
Cc: Jason Low <jason.low2@hp.com>
Link: http://lkml.kernel.org/n/tip-62hcl5wxydmjzd182zhvk89m@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking/mcs_spinlock.h')
| -rw-r--r-- | kernel/locking/mcs_spinlock.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h index f2a5c6360083..a2dbac4aca6b 100644 --- a/kernel/locking/mcs_spinlock.h +++ b/kernel/locking/mcs_spinlock.h @@ -111,4 +111,19 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node) arch_mcs_spin_unlock_contended(&next->locked); } +/* + * Cancellable version of the MCS lock above. + * + * Intended for adaptive spinning of sleeping locks: + * mutex_lock()/rwsem_down_{read,write}() etc. + */ + +struct optimistic_spin_queue { + struct optimistic_spin_queue *next, *prev; + int locked; /* 1 if lock acquired */ +}; + +extern bool osq_lock(struct optimistic_spin_queue **lock); +extern void osq_unlock(struct optimistic_spin_queue **lock); + #endif /* __LINUX_MCS_SPINLOCK_H */ |