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| author | Davidlohr Bueso <davidlohr@hp.com> | 2014-07-30 13:41:54 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-08-13 10:32:02 +0200 |
| commit | 7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9 (patch) | |
| tree | 8701cd9c38afe75bbb39ea00cd15a364837d8ff9 /include | |
| parent | 76916515d9d84e6552ee5e218e0ed566ad75e600 (diff) | |
| download | lwn-7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9.tar.gz lwn-7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9.zip | |
locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate
4badad35 ("locking/mutex: Disable optimistic spinning on some
architectures") added a ARCH_SUPPORTS_ATOMIC_RMW flag to
disable the mutex optimistic feature on specific archs.
Because CONFIG_MUTEX_SPIN_ON_OWNER only depended on DEBUG and
SMP, it was ok to have the ->owner field conditional a bit
flexible. However by adding a new variable to the matter,
we can waste space with the unused field, ie: CONFIG_SMP &&
(!CONFIG_MUTEX_SPIN_ON_OWNER && !CONFIG_DEBUG_MUTEX).
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: aswin@hp.com
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/1406752916-3341-5-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mutex.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 8d5535c58cc2..e4c29418f407 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -52,7 +52,7 @@ struct mutex { atomic_t count; spinlock_t wait_lock; struct list_head wait_list; -#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) +#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER) struct task_struct *owner; #endif #ifdef CONFIG_MUTEX_SPIN_ON_OWNER |