locking/mutexes/mcs: Restructure the MCS lock defines and locking code into its own file

Browse source

We will need the MCS lock code for doing optimistic spinning for rwsem
and queued rwlock.  Extracting the MCS code from mutex.c and put into
its own file allow us to reuse this code easily.

We also inline mcs_spin_lock and mcs_spin_unlock functions
for better efficiency.

Note that using the smp_load_acquire/smp_store_release pair used in
mcs_lock and mcs_unlock is not sufficient to form a full memory barrier
across cpus for many architectures (except x86).  For applications that
absolutely need a full barrier across multiple cpus with mcs_unlock and
mcs_lock pair, smp_mb__after_unlock_lock() should be used after mcs_lock.

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1390347360.3138.63.camel@schen9-DESK
Signed-off-by: Ingo Molnar <mingo@kernel.org>

...

This commit is contained in:

Tim Chen 2014-01-21 15:36:00 -08:00 • committed by Ingo Molnar

parent aff7385b5a

commit e72246748f

3 changed files with 87 additions and 63 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

77

include/linux/mcs_spinlock.h

View file

5

include/linux/mutex.h

View file

68

kernel/locking/mutex.c

View file