user/sven/linux.git/include/linux/mutex.h, branch v3.18.28

locking/Documentation: Move locking related docs into Documentation/locking/

2014-08-13T08:32:03Z

Specifically: Documentation/locking/lockdep-design.txt Documentation/locking/lockstat.txt Documentation/locking/mutex-design.txt Documentation/locking/rt-mutex-design.txt Documentation/locking/rt-mutex.txt Documentation/locking/spinlocks.txt Documentation/locking/ww-mutex-design.txt Signed-off-by: Davidlohr Bueso Acked-by: Randy Dunlap Signed-off-by: Peter Zijlstra Cc: jason.low2@hp.com Cc: aswin@hp.com Cc: Alexei Starovoitov Cc: Al Viro Cc: Andrew Morton Cc: Chris Mason Cc: Dan Streetman Cc: David Airlie Cc: Davidlohr Bueso Cc: David S. Miller Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: Jason Low Cc: Josef Bacik Cc: Kees Cook Cc: Linus Torvalds Cc: Lubomir Rintel Cc: Masanari Iida Cc: Paul E. McKenney Cc: Randy Dunlap Cc: Tim Chen Cc: Vineet Gupta Cc: fengguang.wu@intel.com Link: http://lkml.kernel.org/r/1406752916-3341-6-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar

locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate

2014-08-13T08:32:02Z

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 Acked-by: Jason Low Signed-off-by: Peter Zijlstra Cc: aswin@hp.com Cc: Davidlohr Bueso Cc: Heiko Carstens Cc: Jason Low Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Tim Chen Link: http://lkml.kernel.org/r/1406752916-3341-5-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar

arch, locking: Ciao arch_mutex_cpu_relax()

2014-07-17T10:32:47Z

The arch_mutex_cpu_relax() function, introduced by 34b133f, is hacky and ugly. It was added a few years ago to address the fact that common cpu_relax() calls include yielding on s390, and thus impact the optimistic spinning functionality of mutexes. Nowadays we use this function well beyond mutexes: rwsem, qrwlock, mcs and lockref. Since the macro that defines the call is in the mutex header, any users must include mutex.h and the naming is misleading as well. This patch (i) renames the call to cpu_relax_lowlatency ("relax, but only if you can do it with very low latency") and (ii) defines it in each arch's asm/processor.h local header, just like for regular cpu_relax functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax, and thus we can take it out of mutex.h. While this can seem redundant, I believe it is a good choice as it allows us to move out arch specific logic from generic locking primitives and enables future(?) archs to transparently define it, similarly to System Z. Signed-off-by: Davidlohr Bueso Signed-off-by: Peter Zijlstra Cc: Andrew Morton Cc: Anton Blanchard Cc: Aurelien Jacquiot Cc: Benjamin Herrenschmidt Cc: Bharat Bhushan Cc: Catalin Marinas Cc: Chen Liqin Cc: Chris Metcalf Cc: Christian Borntraeger Cc: Chris Zankel Cc: David Howells Cc: David S. Miller Cc: Deepthi Dharwar Cc: Dominik Dingel Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: Guan Xuetao Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Heiko Carstens Cc: Helge Deller Cc: Hirokazu Takata Cc: Ivan Kokshaysky Cc: James E.J. Bottomley Cc: James Hogan Cc: Jason Wang Cc: Jesper Nilsson Cc: Joe Perches Cc: Jonas Bonn Cc: Joseph Myers Cc: Kees Cook Cc: Koichi Yasutake Cc: Lennox Wu Cc: Linus Torvalds Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Turner Cc: Max Filippov Cc: Michael Neuling Cc: Michal Simek Cc: Mikael Starvik Cc: Nicolas Pitre Cc: Paolo Bonzini Cc: Paul Burton Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Paul Mackerras Cc: Qais Yousef Cc: Qiaowei Ren Cc: Rafael Wysocki Cc: Ralf Baechle Cc: Richard Henderson Cc: Richard Kuo Cc: Russell King Cc: Steven Miao Cc: Steven Rostedt Cc: Stratos Karafotis Cc: Tim Chen Cc: Tony Luck Cc: Vasily Kulikov Cc: Vineet Gupta Cc: Vineet Gupta Cc: Waiman Long Cc: Will Deacon Cc: Wolfram Sang Cc: adi-buildroot-devel@lists.sourceforge.net Cc: linux390@de.ibm.com Cc: linux-alpha@vger.kernel.org Cc: linux-am33-list@redhat.com Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-cris-kernel@axis.com Cc: linux-hexagon@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux@lists.openrisc.net Cc: linux-m32r-ja@ml.linux-m32r.org Cc: linux-m32r@ml.linux-m32r.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-metag@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net Signed-off-by: Ingo Molnar

locking/spinlocks/mcs: Convert osq lock to atomic_t to reduce overhead

2014-07-16T11:28:04Z

The cancellable MCS spinlock is currently used to queue threads that are doing optimistic spinning. It uses per-cpu nodes, where a thread obtaining the lock would access and queue the local node corresponding to the CPU that it's running on. Currently, the cancellable MCS lock is implemented by using pointers to these nodes. In this patch, instead of operating on pointers to the per-cpu nodes, we store the CPU numbers in which the per-cpu nodes correspond to in atomic_t. A similar concept is used with the qspinlock. By operating on the CPU # of the nodes using atomic_t instead of pointers to those nodes, this can reduce the overhead of the cancellable MCS spinlock by 32 bits (on 64 bit systems). Signed-off-by: Jason Low Signed-off-by: Peter Zijlstra Cc: Scott Norton Cc: "Paul E. McKenney" Cc: Dave Chinner Cc: Waiman Long Cc: Davidlohr Bueso Cc: Rik van Riel Cc: Andrew Morton Cc: "H. Peter Anvin" Cc: Steven Rostedt Cc: Tim Chen Cc: Konrad Rzeszutek Wilk Cc: Aswin Chandramouleeswaran Cc: Linus Torvalds Cc: Chris Mason Cc: Heiko Carstens Cc: Josef Bacik Link: http://lkml.kernel.org/r/1405358872-3732-3-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar

locking/spinlocks/mcs: Rename optimistic_spin_queue() to optimistic_spin_node()

2014-07-16T11:28:03Z

Currently, the per-cpu nodes structure for the cancellable MCS spinlock is named "optimistic_spin_queue". However, in a follow up patch in the series we will be introducing a new structure that serves as the new "handle" for the lock. It would make more sense if that structure is named "optimistic_spin_queue". Additionally, since the current use of the "optimistic_spin_queue" structure are "nodes", it might be better if we rename them to "node" anyway. This preparatory patch renames all current "optimistic_spin_queue" to "optimistic_spin_node". Signed-off-by: Jason Low Signed-off-by: Peter Zijlstra Cc: Scott Norton Cc: "Paul E. McKenney" Cc: Dave Chinner Cc: Waiman Long Cc: Davidlohr Bueso Cc: Rik van Riel Cc: Andrew Morton Cc: "H. Peter Anvin" Cc: Steven Rostedt Cc: Tim Chen Cc: Konrad Rzeszutek Wilk Cc: Aswin Chandramouleeswaran Cc: Linus Torvalds Cc: Chris Mason Cc: Heiko Carstens Cc: Josef Bacik Link: http://lkml.kernel.org/r/1405358872-3732-2-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar

locking/mutexes: Introduce cancelable MCS lock for adaptive spinning

2014-03-11T11:14:56Z

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 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 Link: http://lkml.kernel.org/n/tip-62hcl5wxydmjzd182zhvk89m@git.kernel.org Signed-off-by: Ingo Molnar

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

2014-01-28T12:13:27Z

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 Signed-off-by: Tim Chen Signed-off-by: Davidlohr Bueso Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1390347360.3138.63.camel@schen9-DESK Signed-off-by: Ingo Molnar

locking/doc: Update references to kernel/mutex.c

2013-11-11T11:41:33Z

Fix this docbook error: >> docproc: kernel/mutex.c: No such file or directory by updating the stale references to kernel/mutex.c. Reported-by: fengguang.wu@intel.com Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-34pikw1tlsskj65rrt5iusrq@git.kernel.org Signed-off-by: Ingo Molnar

mutex: replace CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX with simple ifdef

2013-09-28T10:46:21Z

Linus suggested to replace #ifndef CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX #define arch_mutex_cpu_relax() cpu_relax() #endif with just a simple #ifndef arch_mutex_cpu_relax # define arch_mutex_cpu_relax() cpu_relax() #endif to get rid of CONFIG_HAVE_CPU_RELAX_SIMPLE. So architectures can simply define arch_mutex_cpu_relax if they want an architecture specific function instead of having to add a select statement in their Kconfig in addition. Suggested-by: Linus Torvalds Signed-off-by: Heiko Carstens

mutex: Move ww_mutex definitions to ww_mutex.h

2013-07-12T10:07:46Z

Move the definitions for wound/wait mutexes out to a separate header, ww_mutex.h. This reduces clutter in mutex.h, and increases readability. Suggested-by: Linus Torvalds Signed-off-by: Maarten Lankhorst Acked-by: Peter Zijlstra Acked-by: Rik van Riel Acked-by: Maarten Lankhorst Cc: Dave Airlie Link: http://lkml.kernel.org/r/51D675DC.3000907@canonical.com [ Tidied up the code a bit. ] Signed-off-by: Ingo Molnar