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2014-12-12linux/interrupt.h: remove the definition of unused tasklet_hi_enableQuentin Lambert1-6/+0
Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-01genirq: Simplify wakeup mechanismThomas Gleixner1-5/+0
Currently we suspend wakeup interrupts by lazy disabling them and check later whether the interrupt has fired, but that's not sufficient for suspend to idle as there is no way to check that once we transitioned into the CPU idle state. So we change the mechanism in the following way: 1) Leave the wakeup interrupts enabled across suspend 2) Add a check to irq_may_run() which is called at the beginning of each flow handler whether the interrupt is an armed wakeup source. This check is basically free as it just extends the existing check for IRQD_IRQ_INPROGRESS. So no new conditional in the hot path. If the IRQD_WAKEUP_ARMED flag is set, then the interrupt is disabled, marked as pending/suspended and the pm core is notified about the wakeup event. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ rjw: syscore.c and put irq_pm_check_wakeup() into pm.c ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-04Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into nextLinus Torvalds1-20/+26
Pull core irq updates from Thomas Gleixner: "The irq department delivers: - Another tree wide update to get rid of the horrible create_irq interface along with its even more horrible variants. That also gets rid of the last leftovers of the initial sparse irq hackery. arch/driver specific changes have been either acked or ignored. - A fix for the spurious interrupt detection logic with threaded interrupts. - A new ARM SoC interrupt controller - The usual pile of fixes and improvements all over the place" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) Documentation: brcmstb-l2: Add Broadcom STB Level-2 interrupt controller binding irqchip: brcmstb-l2: Add Broadcom Set Top Box Level-2 interrupt controller genirq: Improve documentation to match current implementation ARM: iop13xx: fix msi support with sparse IRQ genirq: Provide !SMP stub for irq_set_affinity_notifier() irqchip: armada-370-xp: Move the devicetree binding documentation irqchip: gic: Use mask field in GICC_IAR genirq: Remove dynamic_irq mess ia64: Use irq_init_desc genirq: Replace dynamic_irq_init/cleanup genirq: Remove irq_reserve_irq[s] genirq: Replace reserve_irqs in core code s390: Avoid call to irq_reserve_irqs() s390: Remove pointless arch_show_interrupts() s390: pci: Check return value of alloc_irq_desc() proper sh: intc: Remove pointless irq_reserve_irqs() invocation x86, irq: Remove pointless irq_reserve_irqs() call genirq: Make create/destroy_irq() ia64 private tile: Use SPARSE_IRQ tile: pci: Use irq_alloc/free_hwirq() ...
2014-06-03Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into nextLinus Torvalds1-4/+4
Pull core locking updates from Ingo Molnar: "The main changes in this cycle were: - reduced/streamlined smp_mb__*() interface that allows more usecases and makes the existing ones less buggy, especially in rarer architectures - add rwsem implementation comments - bump up lockdep limits" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) rwsem: Add comments to explain the meaning of the rwsem's count field lockdep: Increase static allocations arch: Mass conversion of smp_mb__*() arch,doc: Convert smp_mb__*() arch,xtensa: Convert smp_mb__*() arch,x86: Convert smp_mb__*() arch,tile: Convert smp_mb__*() arch,sparc: Convert smp_mb__*() arch,sh: Convert smp_mb__*() arch,score: Convert smp_mb__*() arch,s390: Convert smp_mb__*() arch,powerpc: Convert smp_mb__*() arch,parisc: Convert smp_mb__*() arch,openrisc: Convert smp_mb__*() arch,mn10300: Convert smp_mb__*() arch,mips: Convert smp_mb__*() arch,metag: Convert smp_mb__*() arch,m68k: Convert smp_mb__*() arch,m32r: Convert smp_mb__*() arch,ia64: Convert smp_mb__*() ...
2014-05-21Merge branch 'irq/for-net' into irq/coreThomas Gleixner1-20/+26
Reason: Import the change which might be pulled in from net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-21genirq: Provide !SMP stub for irq_set_affinity_notifier()Eyal Perry1-20/+26
Instead of requiring each consumer of the IRQ affinity notifier to have themselves be explicitly dependent on CONFIG_SMP, make the definition of struct irq_affinity_notify to exist independently of that config option and introduce a stub for irq_set_affinity_notifier() under non SMP configuration. Fixes: 2eacc23 ("net/mlx4_core: Enforce irq affinity changes immediatly") Signed-off-by: Eyal Perry <eyalpe@mellanox.com> Signed-off-by: Amir Vadai <amirv@mellanox.com> Cc: Ben Hutchings <bhutchings@solarflare.com> Cc: Yevgeny Petrilin <yevgenyp@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Cc: David S. Miller <davem@davemloft.net> Link: http://lkml.kernel.org/r/1400597820-30685-1-git-send-email-amirv@mellanox.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-07genirq: Provide irq_force_affinity fallback for non-SMPArnd Bergmann1-0/+5
Patch 01f8fa4f01d "genirq: Allow forcing cpu affinity of interrupts" added an irq_force_affinity() function, and 30ccf03b4a6 "clocksource: Exynos_mct: Use irq_force_affinity() in cpu bringup" subsequently uses it. However, the driver can be used with CONFIG_SMP disabled, but the function declaration is only available for CONFIG_SMP, leading to this build error: drivers/clocksource/exynos_mct.c:431:3: error: implicit declaration of function 'irq_force_affinity' [-Werror=implicit-function-declaration] irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); This patch introduces a dummy helper function for the non-SMP case that always returns success, to get rid of the build error. Since the patches causing the problem are marked for stable backports, this one should be as well. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/5619084.0zmrrIUZLV@wuerfel Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-04-28linux/interrupt.h: fix new kernel-doc warningsRandy Dunlap1-2/+2
Fix new kernel-doc warnings in <linux/interrupt.h>: Warning(include/linux/interrupt.h:219): No description found for parameter 'cpumask' Warning(include/linux/interrupt.h:219): Excess function parameter 'mask' description in 'irq_set_affinity' Warning(include/linux/interrupt.h:236): No description found for parameter 'cpumask' Warning(include/linux/interrupt.h:236): Excess function parameter 'mask' description in 'irq_force_affinity' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: http://lkml.kernel.org/r/535DD2FD.7030804@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-04-18arch: Mass conversion of smp_mb__*()Peter Zijlstra1-4/+4
Mostly scripted conversion of the smp_mb__* barriers. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arch@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-17genirq: Allow forcing cpu affinity of interruptsThomas Gleixner1-1/+34
The current implementation of irq_set_affinity() refuses rightfully to route an interrupt to an offline cpu. But there is a special case, where this is actually desired. Some of the ARM SoCs have per cpu timers which require setting the affinity during cpu startup where the cpu is not yet in the online mask. If we can't do that, then the local timer interrupt for the about to become online cpu is routed to some random online cpu. The developers of the affected machines tried to work around that issue, but that results in a massive mess in that timer code. We have a yet unused argument in the set_affinity callbacks of the irq chips, which I added back then for a similar reason. It was never required so it got not used. But I'm happy that I never removed it. That allows us to implement a sane handling of the above scenario. So the affected SoC drivers can add the required force handling to their interrupt chip, switch the timer code to irq_force_affinity() and things just work. This does not affect any existing user of irq_set_affinity(). Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Reported-and-tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Tomasz Figa <t.figa@samsung.com>, Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-19genirq: Provide irq_wake_thread()Thomas Gleixner1-0/+1
In course of the sdhci/sdio discussion with Russell about killing the sdio kthread hackery we discovered the need to be able to wake an interrupt thread from software. The rationale for this is, that sdio hardware can lack proper interrupt support for certain features. So the driver needs to poll the status registers, but at the same time it needs to be woken up by an hardware interrupt. To be able to get rid of the home brewn kthread construct of sdio we need a way to wake an irq thread independent of an actual hardware interrupt. Provide an irq_wake_thread() function which wakes up the thread which is associated to a given dev_id. This allows sdio to invoke the irq thread from the hardware irq handler via the IRQ_WAKE_THREAD return value and provides a possibility to wake it via a timer for the polling scenarios. That allows to simplify the sdio logic significantly. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Chris Ball <chris@printf.net> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140215003823.772565780@linutronix.de
2014-02-09genirq: Add devm_request_any_context_irq()Stephen Boyd1-0/+5
Some drivers use request_any_context_irq() but there isn't a devm_* function for it. Add one so that these drivers don't need to explicitly free the irq on driver detach. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: linux-arm-kernel@lists.infradead.org Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Link: http://lkml.kernel.org/r/1388709460-19222-3-git-send-email-sboyd@codeaurora.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-01-27softirq: use const char * const for softirq_to_name, whitespace neateningJoe Perches1-1/+1
Reduce data size a little. Reduce checkpatch noise. $ size kernel/softirq.o* text data bss dec hex filename 11554 6013 4008 21575 5447 kernel/softirq.o.new 11474 6093 4008 21575 5447 kernel/softirq.o.old Signed-off-by: Joe Perches <joe@perches.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15revert "softirq: Add support for triggering softirq work on softirqs"Christoph Hellwig1-22/+0
This commit was incomplete in that code to remove items from the per-cpu lists was missing and never acquired a user in the 5 years it has been in the tree. We're going to implement what it seems to try to archive in a simpler way, and this code is in the way of doing so. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-10-01irq: Consolidate do_softirq() arch overriden implementationsFrederic Weisbecker1-0/+11
All arch overriden implementations of do_softirq() share the following common code: disable irqs (to avoid races with the pending check), check if there are softirqs pending, then execute __do_softirq() on a specific stack. Consolidate the common parts such that archs only worry about the stack switch. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@au1.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Andrew Morton <akpm@linux-foundation.org>
2013-09-13Remove GENERIC_HARDIRQ config optionMartin Schwidefsky1-72/+3
After the last architecture switched to generic hard irqs the config options HAVE_GENERIC_HARDIRQS & GENERIC_HARDIRQS and the related code for !CONFIG_GENERIC_HARDIRQS can be removed. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-01-11lib: cpu_rmap: avoid flushing all workqueuesDavid Decotigny1-5/+0
In some cases, free_irq_cpu_rmap() is called while holding a lock (eg rtnl). This can lead to deadlocks, because it invokes flush_scheduled_work() which ends up waiting for whole system workqueue to flush, but some pending works might try to acquire the lock we are already holding. This commit uses reference-counting to replace irq_run_affinity_notifiers(). It also removes irq_run_affinity_notifiers() altogether. [akpm@linux-foundation.org: eliminate free_cpu_rmap, rename cpu_rmap_reclaim() to cpu_rmap_release(), propagate kref_put() retval from cpu_rmap_put()] Signed-off-by: David Decotigny <decot@googlers.com> Reviewed-by: Ben Hutchings <bhutchings@solarflare.com> Acked-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Or Gerlitz <ogerlitz@mellanox.com> Acked-by: Amir Vadai <amirv@mellanox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-23time: RCU permitted to stop idle entry via softirqPaul E. McKenney1-0/+2
The can_stop_idle_tick() function complains if a softirq vector is raised too late in the idle-entry process, presumably in order to prevent dangling softirq invocations from being delayed across the full idle period, which might be indefinitely long -- and if softirq was asserted any later than the call to this function, such a delay might well happen. However, RCU needs to be able to use softirq to stop idle entry in order to be able to drain RCU callbacks from the current CPU, which in turn enables faster entry into dyntick-idle mode, which in turn reduces power consumption. Because RCU takes this action at a well-defined point in the idle-entry path, it is safe for RCU to take this approach. This commit therefore silences the error message that is sometimes produced when the going-idle CPU suddenly finds that it has an RCU_SOFTIRQ to process. The error message will continue to be issued for other softirq vectors. Reported-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-19random: final removal of IRQF_SAMPLE_RANDOMTheodore Ts'o1-2/+0
The IRQF_SAMPLE_RANDOM flag is finally gone from the kernel tree, only three years late. :-) Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-05-23genirq: reimplement exit_irq_thread() hook via task_work_add()Oleg Nesterov1-4/+0
exit_irq_thread() and task->irq_thread are needed to handle the unexpected (and unlikely) exit of irq-thread. We can use task_work instead and make this all private to kernel/irq/manage.c, cleanup plus micro-optimization. 1. rename exit_irq_thread() to irq_thread_dtor(), make it static, and move it up before irq_thread(). 2. change irq_thread() to do task_work_add(irq_thread_dtor) at the start and task_work_cancel() before return. tracehook_notify_resume() can never play with kthreads, only do_exit()->exit_task_work() can call the callback and this is what we want. 3. remove task_struct->irq_thread and the special hook in do_exit(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Gordeev <agordeev@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Smith <dsmith@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-04-19genirq: Streamline irq_actionThomas Gleixner1-4/+4
There is no need to have flags as unsigned long. Make it unsigned int and put it together with irq so it does not waste space on 64 bit. Make irq unsigned int while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-28Remove all #inclusions of asm/system.hDavid Howells1-1/+0
Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com>
2012-02-03tracing/softirq: Move __raise_softirq_irqoff() out of headerSteven Rostedt1-6/+1
The __raise_softirq_irqoff() contains a tracepoint. As tracepoints in headers can cause issues, and not to mention, bloats the kernel when they are in a static inline, it is best to move the function that contains the tracepoint out of the header and into softirq.c. Link: http://lkml.kernel.org/r/20120118120711.GB14863@elte.hu Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-10-17genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlierIan Campbell1-0/+3
This adds a mechanism to resume selected IRQs during syscore_resume instead of dpm_resume_noirq. Under Xen we need to resume IRQs associated with IPIs early enough that the resched IPI is unmasked and we can therefore schedule ourselves out of the stop_machine where the suspend/resume takes place. This issue was introduced by 676dc3cf5bc3 "xen: Use IRQF_FORCE_RESUME". Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk Cc: stable@kernel.org (at least to 2.6.32.y) Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-10-03genirq: percpu: allow interrupt type to be set at enable timeMarc Zyngier1-1/+1
As request_percpu_irq() doesn't allow for a percpu interrupt to have its type configured (it is generally impossible to configure it on all CPUs at once), add a 'type' argument to enable_percpu_irq(). This allows some low-level, board specific init code to be switched to a generic API. [ tglx: Added WARN_ON argument ] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Abhijeet Dharmapurikar <adharmap@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-10-03genirq: Add support for per-cpu dev_id interruptsMarc Zyngier1-11/+27
The ARM GIC interrupt controller offers per CPU interrupts (PPIs), which are usually used to connect local timers to each core. Each CPU has its own private interface to the GIC, and only sees the PPIs that are directly connect to it. While these timers are separate devices and have a separate interrupt line to a core, they all use the same IRQ number. For these devices, request_irq() is not the right API as it assumes that an IRQ number is visible by a number of CPUs (through the affinity setting), but makes it very awkward to express that an IRQ number can be handled by all CPUs, and yet be a different interrupt line on each CPU, requiring a different dev_id cookie to be passed back to the handler. The *_percpu_irq() functions is designed to overcome these limitations, by providing a per-cpu dev_id vector: int request_percpu_irq(unsigned int irq, irq_handler_t handler, const char *devname, void __percpu *percpu_dev_id); void free_percpu_irq(unsigned int, void __percpu *); int setup_percpu_irq(unsigned int irq, struct irqaction *new); void remove_percpu_irq(unsigned int irq, struct irqaction *act); void enable_percpu_irq(unsigned int irq); void disable_percpu_irq(unsigned int irq); The API has a number of limitations: - no interrupt sharing - no threading - common handler across all the CPUs Once the interrupt is requested using setup_percpu_irq() or request_percpu_irq(), it must be enabled by each core that wishes its local interrupt to be delivered. Based on an initial patch by Thomas Gleixner. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1316793788-14500-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-07-26atomic: use <linux/atomic.h>Arun Sharma1-1/+1
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-14rcu: Use softirq to address performance regressionShaohua Li1-0/+1
Commit a26ac2455ffcf3(rcu: move TREE_RCU from softirq to kthread) introduced performance regression. In an AIM7 test, this commit degraded performance by about 40%. The commit runs rcu callbacks in a kthread instead of softirq. We observed high rate of context switch which is caused by this. Out test system has 64 CPUs and HZ is 1000, so we saw more than 64k context switch per second which is caused by RCU's per-CPU kthread. A trace showed that most of the time the RCU per-CPU kthread doesn't actually handle any callbacks, but instead just does a very small amount of work handling grace periods. This means that RCU's per-CPU kthreads are making the scheduler do quite a bit of work in order to allow a very small amount of RCU-related processing to be done. Alex Shi's analysis determined that this slowdown is due to lock contention within the scheduler. Unfortunately, as Peter Zijlstra points out, the scheduler's real-time semantics require global action, which means that this contention is inherent in real-time scheduling. (Yes, perhaps someone will come up with a workaround -- otherwise, -rt is not going to do well on large SMP systems -- but this patch will work around this issue in the meantime. And "the meantime" might well be forever.) This patch therefore re-introduces softirq processing to RCU, but only for core RCU work. RCU callbacks are still executed in kthread context, so that only a small amount of RCU work runs in softirq context in the common case. This should minimize ksoftirqd execution, allowing us to skip boosting of ksoftirqd for CONFIG_RCU_BOOST=y kernels. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Tested-by: "Alex,Shi" <alex.shi@intel.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-05-05rcu: move TREE_RCU from softirq to kthreadPaul E. McKenney1-1/+0
If RCU priority boosting is to be meaningful, callback invocation must be boosted in addition to preempted RCU readers. Otherwise, in presence of CPU real-time threads, the grace period ends, but the callbacks don't get invoked. If the callbacks don't get invoked, the associated memory doesn't get freed, so the system is still subject to OOM. But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit moves the callback invocations to a kthread, which can be boosted easily. Also add comments and properly synchronized all accesses to rcu_cpu_kthread_task, as suggested by Lai Jiangshan. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-03-31Fix common misspellingsLucas De Marchi1-2/+2
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-30genirq: Remove now obsolete set_irq_wake()Thomas Gleixner1-8/+0
Missed that one in the big compat remval patch Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-15Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-19/+56
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (116 commits) x86: Enable forced interrupt threading support x86: Mark low level interrupts IRQF_NO_THREAD x86: Use generic show_interrupts x86: ioapic: Avoid redundant lookup of irq_cfg x86: ioapic: Use new move_irq functions x86: Use the proper accessors in fixup_irqs() x86: ioapic: Use irq_data->state x86: ioapic: Simplify irq chip and handler setup x86: Cleanup the genirq name space genirq: Add chip flag to force mask on suspend genirq: Add desc->irq_data accessor genirq: Add comments to Kconfig switches genirq: Fixup fasteoi handler for oneshot mode genirq: Provide forced interrupt threading sched: Switch wait_task_inactive to schedule_hrtimeout() genirq: Add IRQF_NO_THREAD genirq: Allow shared oneshot interrupts genirq: Prepare the handling of shared oneshot interrupts genirq: Make warning in handle_percpu_event useful x86: ioapic: Move trigger defines to io_apic.h ... Fix up trivial(?) conflicts in arch/x86/pci/xen.c due to genirq name space changes clashing with the Xen cleanups. The set_irq_msi() had moved to xen_bind_pirq_msi_to_irq().
2011-03-15Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-0/+7
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits) sched: Resched proper CPU on yield_to() sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks sched: Clean up the IRQ_TIME_ACCOUNTING code sched: Add #ifdef around irq time accounting functions sched, autogroup: Stop claiming ownership of the root task group sched, autogroup: Stop going ahead if autogroup is disabled sched, autogroup, sysctl: Use proc_dointvec_minmax() instead sched: Fix the group_imb logic sched: Clean up some f_b_g() comments sched: Clean up remnants of sd_idle sched: Wholesale removal of sd_idle logic sched: Add yield_to(task, preempt) functionality sched: Use a buddy to implement yield_task_fair() sched: Limit the scope of clear_buddies sched: Check the right ->nr_running in yield_task_fair() sched: Avoid expensive initial update_cfs_load(), on UP too sched: Fix switch_from_fair() sched: Simplify the idle scheduling class softirqs: Account ksoftirqd time as cpustat softirq ...
2011-02-26genirq: Provide forced interrupt threadingThomas Gleixner1-0/+7
Add a commandline parameter "threadirqs" which forces all interrupts except those marked IRQF_NO_THREAD to run threaded. That's mostly a debug option to allow retrieving better debug data from crashing interrupt handlers. If "threadirqs" is not enabled on the kernel command line, then there is no impact in the interrupt hotpath. Architecture code needs to select CONFIG_IRQ_FORCED_THREADING after marking the interrupts which cant be threaded IRQF_NO_THREAD. All interrupts which have IRQF_TIMER set are implict marked IRQF_NO_THREAD. Also all PER_CPU interrupts are excluded. Forced threading hard interrupts also forces all soft interrupt handling into thread context. When enabled it might slow down things a bit, but for debugging problems in interrupt code it's a reasonable penalty as it does not immediately crash and burn the machine when an interrupt handler is buggy. Some test results on a Core2Duo machine: Cache cold run of: # time git grep irq_desc non-threaded threaded real 1m18.741s 1m19.061s user 0m1.874s 0m1.757s sys 0m5.843s 0m5.427s # iperf -c server non-threaded [ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec threaded [ 3] 0.0-10.0 sec 1.09 GBytes 939 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec [ 3] 0.0-10.0 sec 1.09 GBytes 937 Mbits/sec Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.772668648@linutronix.de>
2011-02-25genirq: Add IRQF_NO_THREADThomas Gleixner1-1/+3
Some low level interrupts cannot be threaded even when we force thread all interrupt handlers. Add a flag to annotate such interrupts. Add all timer interrupts to this category by default. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.578893460@linutronix.de>
2011-02-25genirq: Prepare the handling of shared oneshot interruptsThomas Gleixner1-0/+2
For level type interrupts we need to track how many threads are on flight to avoid useless interrupt storms when not all thread handlers have finished yet. Keep track of the woken threads and only unmask when there are no more threads in flight. Yes, I'm lazy and using a bitfield. But not only because I'm lazy, the main reason is that it's way simpler than using a refcount. A refcount based solution would need to keep track of various things like crashing the irq thread, spurious interrupts coming in, disables/enables, free_irq() and some more. The bitfield keeps the tracking simple and makes things just work. It's also nicely confined to the thread code pathes and does not require additional checks all over the place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20110223234956.388095876@linutronix.de>
2011-02-19genirq: Implement generic irq_show_interrupts()Thomas Gleixner1-0/+1
All archs implement show_interrupts() in more or less the same way. That's tons of duplicated code with different bugs with no value. Implement a generic version and deprecate show_interrupts() Unfortunately we need some ifdeffery for !GENERIC_HARDIRQ archs. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-02-19genirq: Move irq thread flags to coreThomas Gleixner1-14/+0
Soleley used in core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-02-19genirq: Namespace cleanupThomas Gleixner1-3/+11
The irq namespace has become quite convoluted. My bad. Clean it up and deprecate the old functions. All new functions follow the scheme: irq number based: irq_set/get/xxx/_xxx(unsigned int irq, ...) irq_data based: irq_data_set/get/xxx/_xxx(struct irq_data *d, ....) irq_desc based: irq_desc_get_xxx(struct irq_desc *desc) Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-02-08Merge branch 'irq/for-xen' into irq/coreThomas Gleixner1-1/+2
irq/for-xen contains new functionality to avoid Xen private irq hackery. That branch has a single irq commit and is pulled by Xen to base their new features on. Merge it into irq/core as other patches modify the same code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-02-08genirq: Add IRQF_FORCE_RESUMEThomas Gleixner1-1/+2
Xen needs to reenable interrupts which are marked IRQF_NO_SUSPEND in the resume path. Add a flag to force the reenabling in the resume code. Tested-and-acked-by: Ian Campbell <Ian.Campbell@eu.citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-26softirqs: Free up pf flag PF_KSOFTIRQDVenkatesh Pallipadi1-0/+7
Cleanup patch, freeing up PF_KSOFTIRQD and use per_cpu ksoftirqd pointer instead, as suggested by Eric Dumazet. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-2-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-22genirq: Add IRQ affinity notifiersBen Hutchings1-1/+32
When initiating I/O on a multiqueue and multi-IRQ device, we may want to select a queue for which the response will be handled on the same or a nearby CPU. This requires a reverse-map of IRQ affinity. Add a notification mechanism to support this. This is based closely on work by Thomas Gleixner <tglx@linutronix.de>. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Cc: linux-net-drivers@solarflare.com Cc: Tom Herbert <therbert@google.com> Cc: David Miller <davem@davemloft.net> LKML-Reference: <1295470904.11126.84.camel@bwh-desktop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-11-10irq: Better struct irqaction layoutEric Dumazet1-3/+3
We currently use kmalloc-96 slab for struct irqaction allocations on 64bit arches. This is unfortunate because of possible false sharing and two cache lines accesses. Move 'name' and 'dir' fields at the end of the structure, and force a suitable alignement. Hot path fields now use one cache line on x86_64. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Reviewed-by: Andi Kleen <andi@firstfloor.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1288865628.2659.69.camel@edumazet-laptop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-10-27Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-1/+1
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (50 commits) perf python scripting: Add futex-contention script perf python scripting: Fixup cut'n'paste error in sctop script perf scripting: Shut up 'perf record' final status perf record: Remove newline character from perror() argument perf python scripting: Support fedora 11 (audit 1.7.17) perf python scripting: Improve the syscalls-by-pid script perf python scripting: print the syscall name on sctop perf python scripting: Improve the syscalls-counts script perf python scripting: Improve the failed-syscalls-by-pid script kprobes: Remove redundant text_mutex lock in optimize x86/oprofile: Fix uninitialized variable use in debug printk tracing: Fix 'faild' -> 'failed' typo perf probe: Fix format specified for Dwarf_Off parameter perf trace: Fix detection of script extension perf trace: Use $PERF_EXEC_PATH in canned report scripts perf tools: Document event modifiers perf tools: Remove direct slang.h include perf_events: Fix for transaction recovery in group_sched_in() perf_events: Revert: Fix transaction recovery in group_sched_in() perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations ...
2010-10-23Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/urgentIngo Molnar1-1/+1
2010-10-23Merge branches 'softirq-for-linus', 'x86-debug-for-linus', 'x86-numa-for-linus', 'x86-quirks-for-linus', 'x86-setup-for-linus', 'x86-uv-for-linus' and 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-1/+0
* 'softirq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softirqs: Make wakeup_softirqd static * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, asm: Restore parentheses around one pushl_cfi argument x86, asm: Fix ancient-GAS workaround x86, asm: Fix CFI macro invocations to deal with shortcomings in gas * 'x86-numa-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, numa: Assign CPUs to nodes in round-robin manner on fake NUMA * 'x86-quirks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: HPET force enable for CX700 / VIA Epia LT * 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, setup: Use string copy operation to optimze copy in kernel compression * 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, UV: Use allocated buffer in tlb_uv.c:tunables_read() * 'x86-vm86-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, vm86: Fix preemption bug for int1 debug and int3 breakpoint handlers.
2010-10-21Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-3/+0
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (96 commits) apic, x86: Use BIOS settings for IBS and MCE threshold interrupt LVT offsets apic, x86: Check if EILVT APIC registers are available (AMD only) x86: ioapic: Call free_irte only if interrupt remapping enabled arm: Use ARCH_IRQ_INIT_FLAGS genirq, ARM: Fix boot on ARM platforms genirq: Fix CONFIG_GENIRQ_NO_DEPRECATED=y build x86: Switch sparse_irq allocations to GFP_KERNEL genirq: Switch sparse_irq allocator to GFP_KERNEL genirq: Make sparse_lock a mutex x86: lguest: Use new irq allocator genirq: Remove the now unused sparse irq leftovers genirq: Sanitize dynamic irq handling genirq: Remove arch_init_chip_data() x86: xen: Sanitise sparse_irq handling x86: Use sane enumeration x86: uv: Clean up the direct access to irq_desc x86: Make io_apic.c local functions static genirq: Remove irq_2_iommu x86: Speed up the irq_remapped check in hot pathes intr_remap: Simplify the code further ... Fix up trivial conflicts in arch/x86/Kconfig
2010-10-21tracing: Cleanup the convoluted softirq tracepointsThomas Gleixner1-1/+1
With the addition of trace_softirq_raise() the softirq tracepoint got even more convoluted. Why the tracepoints take two pointers to assign an integer is beyond my comprehension. But adding an extra case which treats the first pointer as an unsigned long when the second pointer is NULL including the back and forth type casting is just horrible. Convert the softirq tracepoints to take a single unsigned int argument for the softirq vector number and fix the call sites. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <alpine.LFD.2.00.1010191428560.6815@localhost6.localdomain6> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: mathieu.desnoyers@efficios.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org>
2010-10-12genirq: Remove arch_init_chip_data()Thomas Gleixner1-3/+0
This function should have not been there in the first place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@elte.hu>
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