linux/kernel/spinlock.c, branch v2.6.30

Allow rwlocks to re-enable interrupts

2009-04-03T02:05:11Z

Pass the original flags to rwlock arch-code, so that it can re-enable interrupts if implemented for that architecture. Initially, make __raw_read_lock_flags and __raw_write_lock_flags stubs which just do the same thing as non-flags variants. Signed-off-by: Petr Tesarik Signed-off-by: Robin Holt Acked-by: Peter Zijlstra Cc: Acked-by: Ingo Molnar Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Factor out #ifdefs from kernel/spinlock.c to LOCK_CONTENDED_FLAGS

2009-04-03T02:05:10Z

SGI has observed that on large systems, interrupts are not serviced for a long period of time when waiting for a rwlock. The following patch series re-enables irqs while waiting for the lock, resembling the code which is already there for spinlocks. I only made the ia64 version, because the patch adds some overhead to the fast path. I assume there is currently no demand to have this for other architectures, because the systems are not so large. Of course, the possibility to implement raw_{read|write}_lock_flags for any architecture is still there. This patch: The new macro LOCK_CONTENDED_FLAGS expands to the correct implementation depending on the config options, so that IRQ's are re-enabled when possible, but they remain disabled if CONFIG_LOCKDEP is set. Signed-off-by: Petr Tesarik Signed-off-by: Robin Holt Cc: Cc: Ingo Molnar Cc: Peter Zijlstra Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lockdep: spin_lock_nest_lock(), checkpatch fixes

2008-08-13T11:56:51Z

fix: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable #46: FILE: kernel/spinlock.c:326: +EXPORT_SYMBOL(_spin_lock_nest_lock); total: 0 errors, 1 warnings, 26 lines checked Signed-off-by: Andrew Morton Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar

lockdep: spin_lock_nest_lock()

2008-08-11T07:30:24Z

Expose the new lock protection lock. This can be used to annotate places where we take multiple locks of the same class and avoid deadlocks by always taking another (top-level) lock first. NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar

ftrace: lockdep notrace annotations

2008-05-23T18:39:40Z

Add notrace annotations to lockdep to keep ftrace from causing recursive problems with lock tracing and debugging. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

spinlock: lockbreak cleanup

2008-01-30T12:31:20Z

The break_lock data structure and code for spinlocks is quite nasty. Not only does it double the size of a spinlock but it changes locking to a potentially less optimal trylock. Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a __raw_spin_is_contended that uses the lock data itself to determine whether there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is not set. Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to decouple it from the spinlock implementation, and make it typesafe (rwlocks do not have any need_lockbreak sites -- why do they even get bloated up with that break_lock then?). Signed-off-by: Nick Piggin Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex

2007-07-19T17:04:49Z

Call the new lockstat tracking functions from the various lock primitives. Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Acked-by: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lockdep: sanitise CONFIG_PROVE_LOCKING

2007-07-19T17:04:49Z

Ensure that all of the lock dependency tracking code is under CONFIG_PROVE_LOCKING. This allows us to use the held lock tracking code for other purposes. Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Acked-by: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] lockdep: spin_lock_irqsave_nested()

2006-11-25T21:28:34Z

Introduce spin_lock_irqsave_nested(); implementation from: http://lkml.org/lkml/2006/6/1/122 Patch from: http://lkml.org/lkml/2006/9/13/258 [akpm@osdl.org: two compile fixes] Signed-off-by: Arjan van de Ven Signed-off-by: Jiri Kosina Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Directed yield: cpu_relax variants for spinlocks and rw-locks

2006-10-01T07:39:21Z

On systems running with virtual cpus there is optimization potential in regard to spinlocks and rw-locks. If the virtual cpu that has taken a lock is known to a cpu that wants to acquire the same lock it is beneficial to yield the timeslice of the virtual cpu in favour of the cpu that has the lock (directed yield). With CONFIG_PREEMPT="n" this can be implemented by the architecture without common code changes. Powerpc already does this. With CONFIG_PREEMPT="y" the lock loops are coded with _raw_spin_trylock, _raw_read_trylock and _raw_write_trylock in kernel/spinlock.c. If the lock could not be taken cpu_relax is called. A directed yield is not possible because cpu_relax doesn't know anything about the lock. To be able to yield the lock in favour of the current lock holder variants of cpu_relax for spinlocks and rw-locks are needed. The new _raw_spin_relax, _raw_read_relax and _raw_write_relax primitives differ from cpu_relax insofar that they have an argument: a pointer to the lock structure. Signed-off-by: Martin Schwidefsky Cc: Ingo Molnar Cc: Paul Mackerras Cc: Haavard Skinnemoen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds