user/sven/linux.git/kernel/softirq.c, branch v4.2.4

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-02-09T23:24:03Z

Pull core locking updates from Ingo Molnar: "The main changes are: - mutex, completions and rtmutex micro-optimizations - lock debugging fix - various cleanups in the MCS and the futex code" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/rtmutex: Optimize setting task running after being blocked locking/rwsem: Use task->state helpers sched/completion: Add lock-free checking of the blocking case sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state locking/mutex: Explicitly mark task as running after wakeup futex: Fix argument handling in futex_lock_pi() calls doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants locking/Documentation: Update code path softirq/preempt: Add missing current->preempt_disable_ip update locking/osq: No need for load/acquire when acquire-polling locking/mcs: Better differentiate between MCS variants locking/mutex: Introduce ww_mutex_set_context_slowpath() locking/mutex: Move MCS related comments to proper location locking/mutex: Checking the stamp is WW only

ksoftirqd: Use new cond_resched_rcu_qs() function

2015-01-14T21:20:26Z

Simplify run_ksoftirqd() by using the new cond_resched_rcu_qs() function that conditionally reschedules, but unconditionally supplies an RCU quiescent state. This commit is separate from the previous commit by Calvin Owens because Calvin's approach can be backported, while this commit cannot be. The reason that this commit cannot be backported is that cond_resched_rcu_qs() does not always provide the needed quiescent state in earlier kernels. Signed-off-by: Paul E. McKenney

ksoftirqd: Enable IRQs and call cond_resched() before poking RCU

2015-01-14T21:18:58Z

While debugging an issue with excessive softirq usage, I encountered the following note in commit 3e339b5dae24a706 ("softirq: Use hotplug thread infrastructure"): [ paulmck: Call rcu_note_context_switch() with interrupts enabled. ] ...but despite this note, the patch still calls RCU with IRQs disabled. This seemingly innocuous change caused a significant regression in softirq CPU usage on the sending side of a large TCP transfer (~1 GB/s): when introducing 0.01% packet loss, the softirq usage would jump to around 25%, spiking as high as 50%. Before the change, the usage would never exceed 5%. Moving the call to rcu_note_context_switch() after the cond_sched() call, as it was originally before the hotplug patch, completely eliminated this problem. Signed-off-by: Calvin Owens Cc: stable@vger.kernel.org Signed-off-by: Paul E. McKenney

softirq/preempt: Add missing current->preempt_disable_ip update

2015-01-14T14:16:21Z

While debugging some "sleeping function called from invalid context" bug I realized that the debugging message "Preemption disabled at:" pointed to an incorrect function. In particular if the last function/action that disabled preemption was spin_lock_bh() then current->preempt_disable_ip won't be updated. The reason for this is that __local_bh_disable_ip() will increase preempt_count manually instead of calling preempt_count_add(), which would handle the update correctly. It look like the manual handling was done to work around some lockdep issue. So add the missing update of current->preempt_disable_ip to __local_bh_disable_ip() as well. Signed-off-by: Heiko Carstens Signed-off-by: Peter Zijlstra (Intel) Cc: Paul E. McKenney Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20150107090441.GC4365@osiris Signed-off-by: Ingo Molnar

rcu: Remove "cpu" argument to rcu_note_context_switch()

2014-11-04T03:20:34Z

The "cpu" argument to rcu_note_context_switch() is always the current CPU, so drop it. This in turn allows the "cpu" argument to rcu_preempt_note_context_switch() to be removed, which allows the sole use of "cpu" in both functions to be replaced with a this_cpu_ptr(). Again, the anticipated cross-CPU uses of these functions has been replaced by NO_HZ_FULL. Signed-off-by: Paul E. McKenney Reviewed-by: Pranith Kumar

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15T05:48:18Z

Pull percpu consistent-ops changes from Tejun Heo: "Way back, before the current percpu allocator was implemented, static and dynamic percpu memory areas were allocated and handled separately and had their own accessors. The distinction has been gone for many years now; however, the now duplicate two sets of accessors remained with the pointer based ones - this_cpu_*() - evolving various other operations over time. During the process, we also accumulated other inconsistent operations. This pull request contains Christoph's patches to clean up the duplicate accessor situation. __get_cpu_var() uses are replaced with with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr(). Unfortunately, the former sometimes is tricky thanks to C being a bit messy with the distinction between lvalues and pointers, which led to a rather ugly solution for cpumask_var_t involving the introduction of this_cpu_cpumask_var_ptr(). This converts most of the uses but not all. Christoph will follow up with the remaining conversions in this merge window and hopefully remove the obsolete accessors" * 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits) irqchip: Properly fetch the per cpu offset percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write. percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t Revert "powerpc: Replace __get_cpu_var uses" percpu: Remove __this_cpu_ptr clocksource: Replace __this_cpu_ptr with raw_cpu_ptr sparc: Replace __get_cpu_var uses avr32: Replace __get_cpu_var with __this_cpu_write blackfin: Replace __get_cpu_var uses tile: Use this_cpu_ptr() for hardware counters tile: Replace __get_cpu_var uses powerpc: Replace __get_cpu_var uses alpha: Replace __get_cpu_var ia64: Replace __get_cpu_var uses s390: cio driver &__get_cpu_var replacements s390: Replace __get_cpu_var uses mips: Replace __get_cpu_var uses MIPS: Replace __get_cpu_var uses in FPU emulator. arm: Replace __this_cpu_ptr with raw_cpu_ptr ...

rcu: Per-CPU operation cleanups to rcu_*_qs() functions

2014-09-07T23:27:35Z

The rcu_bh_qs(), rcu_preempt_qs(), and rcu_sched_qs() functions use old-style per-CPU variable access and write to ->passed_quiesce even if it is already set. This commit therefore updates to use the new-style per-CPU variable access functions and avoids the spurious writes. This commit also eliminates the "cpu" argument to these functions because they are always invoked on the indicated CPU. Reported-by: Peter Zijlstra Signed-off-by: Paul E. McKenney

time: Replace __get_cpu_var uses

2014-08-26T17:45:44Z

Convert uses of __get_cpu_var for creating a address from a percpu offset to this_cpu_ptr. The two cases where get_cpu_var is used to actually access a percpu variable are changed to use this_cpu_read/raw_cpu_read. Reviewed-by: Thomas Gleixner Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

2014-05-22T09:36:10Z

Pull RCU updates from Paul E. McKenney: " 1. Update RCU documentation. These were posted to LKML at https://lkml.org/lkml/2014/4/28/634. 2. Miscellaneous fixes. These were posted to LKML at https://lkml.org/lkml/2014/4/28/645. 3. Torture-test changes. These were posted to LKML at https://lkml.org/lkml/2014/4/28/667. 4. Variable-name renaming cleanup, sent separately due to conflicts. This was posted to LKML at https://lkml.org/lkml/2014/5/13/854. 5. Patch to suppress RCU stall warnings while sysrq requests are being processed. This patch is the RCU portions of the patch that Rik posted to LKML at https://lkml.org/lkml/2014/4/29/457. The reason for pushing this patch ahead instead of waiting until 3.17 is that the NMI-based stack traces are messing up sysrq output, and in some cases also messing up the system as well." Signed-off-by: Ingo Molnar

asmlinkage: Add explicit __visible to drivers/, lib/, kernel/*

2014-05-05T23:07:46Z

As requested by Linus add explicit __visible to the asmlinkage users. This marks functions visible to assembler. Tree sweep for rest of tree. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1398984278-29319-4-git-send-email-andi@firstfloor.org Signed-off-by: H. Peter Anvin