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authorDavidlohr Bueso <davidlohr@hp.com>2014-07-30 13:41:54 -0700
committerIngo Molnar <mingo@kernel.org>2014-08-13 10:32:02 +0200
commit7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9 (patch)
tree8701cd9c38afe75bbb39ea00cd15a364837d8ff9 /include/linux/mutex.h
parent76916515d9d84e6552ee5e218e0ed566ad75e600 (diff)
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/linux/mutex.h')
-rw-r--r--include/linux/mutex.h2
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