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* locking/mcs: Better differentiate between MCS variantsDavidlohr Bueso2015-01-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | We have two flavors of the MCS spinlock: standard and cancelable (OSQ). While each one is independent of the other, we currently mix and match them. This patch: - Moves the OSQ code out of mcs_spinlock.h (which only deals with the traditional version) into include/linux/osq_lock.h. No unnecessary code is added to the more global header file, anything locks that make use of OSQ must include it anyway. - Renames mcs_spinlock.c to osq_lock.c. This file only contains osq code. - Introduces a CONFIG_LOCK_SPIN_ON_OWNER in order to only build osq_lock if there is support for it. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Waiman Long <Waiman.Long@hp.com> Link: http://lkml.kernel.org/r/1420573509-24774-5-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNERDavidlohr Bueso2014-07-161-0/+4
| | | | | | | | | | | | | | | | | | | | | | Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER), encapsulate the dependencies for rwsem optimistic spinning. No logical changes here as it continues to depend on both SMP and the XADD algorithm variant. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Acked-by: Jason Low <jason.low2@hp.com> [ Also make it depend on ARCH_SUPPORTS_ATOMIC_RMW. ] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1405112406-13052-2-git-send-email-davidlohr@hp.com Cc: aswin@hp.com Cc: Chris Mason <clm@fb.com> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: Josef Bacik <jbacik@fusionio.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Waiman Long <Waiman.Long@hp.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/mutex: Disable optimistic spinning on some architecturesPeter Zijlstra2014-07-161-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The optimistic spin code assumes regular stores and cmpxchg() play nice; this is found to not be true for at least: parisc, sparc32, tile32, metag-lock1, arc-!llsc and hexagon. There is further wreckage, but this in particular seemed easy to trigger, so blacklist this. Opt in for known good archs. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Jason Low <jason.low2@hp.com> Cc: Waiman Long <waiman.long@hp.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: John David Anglin <dave.anglin@bell.net> Cc: James Hogan <james.hogan@imgtec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: stable@vger.kernel.org Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/rwlocks: Introduce 'qrwlocks' - fair, queued rwlocksWaiman Long2014-06-061-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This rwlock uses the arch_spin_lock_t as a waitqueue, and assuming the arch_spin_lock_t is a fair lock (ticket,mcs etc..) the resulting rwlock is a fair lock. It fits in the same 8 bytes as the regular rwlock_t by folding the reader and writer count into a single integer, using the remaining 4 bytes for the arch_spinlock_t. Architectures that can single-copy adress bytes can optimize queue_write_unlock() with a 0 write to the LSB (the write count). Performance as measured by Davidlohr Bueso (rwlock_t -> qrwlock_t): +--------------+-------------+---------------+ | Workload | #users | delta | +--------------+-------------+---------------+ | alltests | > 1400 | -4.83% | | custom | 0-100,> 100 | +1.43%,-1.57% | | high_systime | > 1000 | -2.61 | | shared | all | +0.32 | +--------------+-------------+---------------+ http://www.stgolabs.net/qrwlock-stuff/aim7-results-vs-rwsem_optsin/ Signed-off-by: Waiman Long <Waiman.Long@hp.com> [peterz: near complete rewrite] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Paul E.McKenney" <paulmck@linux.vnet.ibm.com> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-gac1nnl3wvs2ij87zv2xkdzq@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH"Paul Bolle2013-05-281-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Kconfig symbols ARCH_INLINE_READ_UNLOCK_IRQ, ARCH_INLINE_SPIN_UNLOCK_IRQ, and ARCH_INLINE_WRITE_UNLOCK_IRQ were added in v2.6.33, but have never actually been used. Ingo Molnar spotted that this is caused by three identical copy/paste erros. Eg, the Kconfig entry for INLINE_READ_UNLOCK_IRQ has an (optional) dependency on: ARCH_INLINE_READ_UNLOCK_BH were it apparently should depend on: ARCH_INLINE_READ_UNLOCK_IRQ instead. Likewise for the Kconfig entries for INLINE_SPIN_UNLOCK_IRQ and INLINE_WRITE_UNLOCK_IRQ. Fix these three errors. This never really caused any real problems as these symbols are set (or unset) in a group - but it's worth fixing it nevertheless. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1368780693.1350.228.camel@x61.thuisdomein Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking: Adjust spin lock inlining Kconfig optionsJan Beulich2012-09-131-40/+63
| | | | | | | | | | | | | | | | | Break out the DEBUG_SPINLOCK dependency (requires moving up UNINLINE_SPIN_UNLOCK, as this was the only one in that block not depending on that option). Avoid putting values not selected into the resulting .config - they are not useful for anything, make the output less legible, and just consume space: Use "depends on" rather than directly setting the default from the combined dependency values. Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/504DF2AC020000780009A2DF@nat28.tlf.novell.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/kconfig: Simplify INLINE_SPIN_UNLOCK usageRaghavendra K T2012-03-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Get rid of INLINE_SPIN_UNLOCK entirely replacing it with UNINLINE_SPIN_UNLOCK instead of the reverse meaning. Whoever wants to change the default spinlock inlining behavior and uninline the spinlocks for some weird reason, such as spinlock debugging, paravirt etc. can now all just select UNINLINE_SPIN_UNLOCK Original discussion at: https://lkml.org/lkml/2012/3/21/357 Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Chris Zankel <chris@zankel.net> Cc: linux-mips@linux-mips.org Link: http://lkml.kernel.org/r/20120322095502.30866.75756.sendpatchset@codeblue [ tidied up the changelog a bit ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* arch:Kconfig.locks Remove unused config option.Justin P. Mattock2011-04-101-1/+1
| | | | | | | Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* mutex: Better control mutex adaptive spinning configFrederic Weisbecker2009-12-031-0/+3
| | | | | | | | | | | | Introduce CONFIG_MUTEX_SPIN_ON_OWNER so that we can centralize in a single place the conditions that determine its definition and use. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1259783357-8542-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org>
* locking: Make inlining decision Kconfig basedThomas Gleixner2009-11-131-0/+199
commit 892a7c67 (locking: Allow arch-inlined spinlocks) implements the selection of which lock functions are inlined based on defines in arch/.../spinlock.h: #define __always_inline__LOCK_FUNCTION Despite of the name __always_inline__* the lock functions can be built out of line depending on config options. Also if the arch does not set some inline defines the generic code might set them; again depending on config options. This makes it unnecessary hard to figure out when and which lock functions are inlined. Aside of that it makes it way harder and messier for -rt to manipulate the lock functions. Convert the inlining decision to CONFIG switches. Each lock function is inlined depending on CONFIG_INLINE_*. The configs implement the existing dependencies. The architecture code can select ARCH_INLINE_* to signal that it wants the corresponding lock function inlined. ARCH_INLINE_* is necessary as Kconfig ignores "depends on" restrictions when a config element is selected. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20091109151428.504477141@linutronix.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>