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* cpu: introduce clear_tasks_mm_cpumask() helperAnton Vorontsov2012-05-311-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many architectures clear tasks' mm_cpumask like this: read_lock(&tasklist_lock); for_each_process(p) { if (p->mm) cpumask_clear_cpu(cpu, mm_cpumask(p->mm)); } read_unlock(&tasklist_lock); Depending on the context, the code above may have several problems, such as: 1. Working with task->mm w/o getting mm or grabing the task lock is dangerous as ->mm might disappear (exit_mm() assigns NULL under task_lock(), so tasklist lock is not enough). 2. Checking for process->mm is not enough because process' main thread may exit or detach its mm via use_mm(), but other threads may still have a valid mm. This patch implements a small helper function that does things correctly, i.e.: 1. We take the task's lock while whe handle its mm (we can't use get_task_mm()/mmput() pair as mmput() might sleep); 2. To catch exited main thread case, we use find_lock_task_mm(), which walks up all threads and returns an appropriate task (with task lock held). Also, Per Peter Zijlstra's idea, now we don't grab tasklist_lock in the new helper, instead we take the rcu read lock. We can do this because the function is called after the cpu is taken down and marked offline, so no new tasks will get this cpu set in their mm mask. Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Cc: Richard Weinberger <richard@nod.at> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: Remove stale power aware scheduling remnants and dysfunctional knobsPeter Zijlstra2012-05-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's been broken forever (i.e. it's not scheduling in a power aware fashion), as reported by Suresh and others sending patches, and nobody cares enough to fix it properly ... so remove it to make space free for something better. There's various problems with the code as it stands today, first and foremost the user interface which is bound to topology levels and has multiple values per level. This results in a state explosion which the administrator or distro needs to master and almost nobody does. Furthermore large configuration state spaces aren't good, it means the thing doesn't just work right because it's either under so many impossibe to meet constraints, or even if there's an achievable state workloads have to be aware of it precisely and can never meet it for dynamic workloads. So pushing this kind of decision to user-space was a bad idea even with a single knob - it's exponentially worse with knobs on every node of the topology. There is a proposal to replace the user interface with a single 3 state knob: sched_balance_policy := { performance, power, auto } where 'auto' would be the preferred default which looks at things like Battery/AC mode and possible cpufreq state or whatever the hw exposes to show us power use expectations - but there's been no progress on it in the past many months. Aside from that, the actual implementation of the various knobs is known to be broken. There have been sporadic attempts at fixing things but these always stop short of reaching a mergable state. Therefore this wholesale removal with the hopes of spurring people who care to come forward once again and work on a coherent replacement. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1326104915.2442.53.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'device-for-3.4' of ↵Linus Torvalds2012-03-241-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull <linux/device.h> avoidance patches from Paul Gortmaker: "Nearly every subsystem has some kind of header with a proto like: void foo(struct device *dev); and yet there is no reason for most of these guys to care about the sub fields within the device struct. This allows us to significantly reduce the scope of headers including headers. For this instance, a reduction of about 40% is achieved by replacing the include with the simple fact that the device is some kind of a struct. Unlike the much larger module.h cleanup, this one is simply two commits. One to fix the implicit <linux/device.h> users, and then one to delete the device.h includes from the linux/include/ dir wherever possible." * tag 'device-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: device.h: audit and cleanup users in main include dir device.h: cleanup users outside of linux/include (C files)
| * device.h: audit and cleanup users in main include dirPaul Gortmaker2012-03-161-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The <linux/device.h> header includes a lot of stuff, and it in turn gets a lot of use just for the basic "struct device" which appears so often. Clean up the users as follows: 1) For those headers only needing "struct device" as a pointer in fcn args, replace the include with exactly that. 2) For headers not really using anything from device.h, simply delete the include altogether. 3) For headers relying on getting device.h implicitly before being included themselves, now explicitly include device.h 4) For files in which doing #1 or #2 uncovers an implicit dependency on some other header, fix by explicitly adding the required header(s). Any C files that were implicitly relying on device.h to be present have already been dealt with in advance. Total removals from #1 and #2: 51. Total additions coming from #3: 9. Total other implicit dependencies from #4: 7. As of 3.3-rc1, there were 110, so a net removal of 42 gives about a 38% reduction in device.h presence in include/* Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* | CPU: Introduce ARCH_HAS_CPU_AUTOPROBE and X86 partsThomas Renninger2012-01-261-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | This patch is based on Andi Kleen's work: Implement autoprobing/loading of modules serving CPU specific features (x86cpu autoloading). And Kay Siever's work to get rid of sysdev cpu structures and making use of struct device instead. Before, the cpuid driver had to be loaded to get the x86cpu autoloading feature. With this patch autoloading works through the /sys/devices/system/cpu object Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Dave Jones <davej@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Huang Ying <ying.huang@intel.com> Cc: Len Brown <lenb@kernel.org> Acked-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Merge branch 'driver-core-next' of ↵Linus Torvalds2012-01-071-9/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core * 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits) arm: fix up some samsung merge sysdev conversion problems firmware: Fix an oops on reading fw_priv->fw in sysfs loading file Drivers:hv: Fix a bug in vmbus_driver_unregister() driver core: remove __must_check from device_create_file debugfs: add missing #ifdef HAS_IOMEM arm: time.h: remove device.h #include driver-core: remove sysdev.h usage. clockevents: remove sysdev.h arm: convert sysdev_class to a regular subsystem arm: leds: convert sysdev_class to a regular subsystem kobject: remove kset_find_obj_hinted() m86k: gpio - convert sysdev_class to a regular subsystem mips: txx9_sram - convert sysdev_class to a regular subsystem mips: 7segled - convert sysdev_class to a regular subsystem sh: dma - convert sysdev_class to a regular subsystem sh: intc - convert sysdev_class to a regular subsystem power: suspend - convert sysdev_class to a regular subsystem power: qe_ic - convert sysdev_class to a regular subsystem power: cmm - convert sysdev_class to a regular subsystem s390: time - convert sysdev_class to a regular subsystem ... Fix up conflicts with 'struct sysdev' removal from various platform drivers that got changed: - arch/arm/mach-exynos/cpu.c - arch/arm/mach-exynos/irq-eint.c - arch/arm/mach-s3c64xx/common.c - arch/arm/mach-s3c64xx/cpu.c - arch/arm/mach-s5p64x0/cpu.c - arch/arm/mach-s5pv210/common.c - arch/arm/plat-samsung/include/plat/cpu.h - arch/powerpc/kernel/sysfs.c and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
| * cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystemKay Sievers2011-12-211-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem and converts the devices to regular devices. The sysdev drivers are implemented as subsystem interfaces now. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Userspace relies on events and generic sysfs subsystem infrastructure from sysdev devices, which are made available with this conversion. Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@amd64.org> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Len Brown <lenb@kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | driver-core/cpu: Expose hotpluggability to the rest of the kernelJosh Triplett2011-12-111-0/+1
|/ | | | | | | | | | | | | | | | | | When architectures register CPUs, they indicate whether the CPU allows hotplugging; notably, x86 and ARM don't allow hotplugging CPU 0. Userspace can easily query the hotpluggability of a CPU via sysfs; however, the kernel has no convenient way of accessing that property in an architecture-independent way. While the kernel can simply try it and see, some code needs to distinguish between "hotplug failed" and "hotplug has no hope of working on this CPU"; for example, rcutorture's CPU hotplug tests want to avoid drowning out real hotplug failures with expected failures. Expose this property via a new cpu_is_hotpluggable function, so that the rest of the kernel can access it in an architecture-independent way. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* PM / Sleep: Remove unused symbol 'suspend_cpu_hotplug'Srivatsa S. Bhat2011-11-041-4/+0
| | | | | | | | | | Remove the suspend_cpu_hotplug declaration, which doesn't correspond to an existing variable. [rjw: Added the changelog.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* notifiers: cpu: move cpu notifiers into cpu.hAmerigo Wang2011-07-251-0/+33
| | | | | | | | | | | | | | | | | | | | | | | | We presently define all kinds of notifiers in notifier.h. This is not necessary at all, since different subsystems use different notifiers, they are almost non-related with each other. This can also save much build time. Suppose I add a new netdevice event, really I don't have to recompile all the source, just network related. Without this patch, all the source will be recompiled. I move the notify events near to their subsystem notifier registers, so that they can be found more easily. This patch: It is not necessary to share the same notifier.h. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* driver core: prune docs about device_interfaceBrandon Philips2010-11-101-5/+0
| | | | | | | | drivers/base/intf.c was removed before the beginning of (git) time but its Documentation stuck around. Remove it. Signed-off-by: Brandon Philips <brandon@ifup.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* workqueue: reimplement CPU hotplugging support using trusteeTejun Heo2010-06-291-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | Reimplement CPU hotplugging support using trustee thread. On CPU down, a trustee thread is created and each step of CPU down is executed by the trustee and workqueue_cpu_callback() simply drives and waits for trustee state transitions. CPU down operation no longer waits for works to be drained but trustee sticks around till all pending works have been completed. If CPU is brought back up while works are still draining, workqueue_cpu_callback() tells trustee to step down and tell workers to rebind to the cpu. As it's difficult to tell whether cwqs are empty if it's freezing or frozen, trustee doesn't consider draining to be complete while a gcwq is freezing or frozen (tracked by new GCWQ_FREEZING flag). Also, workers which get unbound from their cpu are marked with WORKER_ROGUE. Trustee based implementation doesn't bring any new feature at this point but it will be used to manage worker pool when dynamic shared worker pool is implemented. Signed-off-by: Tejun Heo <tj@kernel.org>
* sched: adjust when cpu_active and cpuset configurations are updated during ↵Tejun Heo2010-06-081-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpu on/offlining Currently, when a cpu goes down, cpu_active is cleared before CPU_DOWN_PREPARE starts and cpuset configuration is updated from a default priority cpu notifier. When a cpu is coming up, it's set before CPU_ONLINE but cpuset configuration again is updated from the same cpu notifier. For cpu notifiers, this presents an inconsistent state. Threads which a CPU_DOWN_PREPARE notifier expects to be bound to the CPU can be migrated to other cpus because the cpu is no more inactive. Fix it by updating cpu_active in the highest priority cpu notifier and cpuset configuration in the second highest when a cpu is coming up. Down path is updated similarly. This guarantees that all other cpu notifiers see consistent cpu_active and cpuset configuration. cpuset_track_online_cpus() notifier is converted to cpuset_update_active_cpus() which just updates the configuration and now called from cpuset_cpu_[in]active() notifiers registered from sched_init_smp(). If cpuset is disabled, cpuset_update_active_cpus() degenerates into partition_sched_domains() making separate notifier for !CONFIG_CPUSETS unnecessary. This problem is triggered by cmwq. During CPU_DOWN_PREPARE, hotplug callback creates a kthread and kthread_bind()s it to the target cpu, and the thread is expected to run on that cpu. * Ingo's test discovered __cpuinit/exit markups were incorrect. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Menage <menage@google.com>
* sched: define and use CPU_PRI_* enums for cpu notifier prioritiesTejun Heo2010-06-081-0/+9
| | | | | | | | | | | | Instead of hardcoding priority 10 and 20 in sched and perf, collect them into CPU_PRI_* enums. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
* powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs ↵Gautham R Shenoy2009-12-091-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | deallocate Currently the cpu-allocation/deallocation process comprises of two steps: - Set the indicators and to update the device tree with DLPAR node information. - Online/offline the allocated/deallocated CPU. This is achieved by writing to the sysfs tunables "probe" during allocation and "release" during deallocation. At the sametime, the userspace can independently online/offline the CPUs of the system using the sysfs tunable "online". It is quite possible that when a userspace tool offlines a CPU for the purpose of deallocation and is in the process of updating the device tree, some other userspace tool could bring the CPU back online by writing to the "online" sysfs tunable thereby causing the deallocate process to fail. The solution to this is to serialize writes to the "probe/release" sysfs tunable with the writes to the "online" sysfs tunable. This patch employs a mutex to provide this serialization, which is a no-op on all architectures except PPC_PSERIES Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* sysfs/cpu: Add probe/release filesNathan Fontenot2009-12-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | Version 3 of this patch is updated with documentation added to Documentation/ABI. There are no changes to any of the C code from v2 of the patch. In order to support kernel DLPAR of CPU resources we need to provide an interface to add (probe) and remove (release) the resource from the system. This patch Creates new generic probe and release sysfs files to facilitate cpu probe/release. The probe/release interface provides for allowing each arch to supply their own routines for implementing the backend of adding and removing cpus to/from the system. This also creates the powerpc specific stubs to handle the arch callouts from writes to the sysfs files. The creation and use of these files is regulated by the CONFIG_ARCH_CPU_PROBE_RELEASE option so that only architectures that need the capability will have the files created. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* cpu hotplug: Introduce cpu_notifier() to handle !HOTPLUG_CPU casePaul E. McKenney2009-08-151-5/+12
| | | | | | | | | | | | | | | | | | | | | | | This patch introduces a new cpu_notifier() API that is similar to hotcpu_notifier(), but which also notifies of CPUs coming online during boot in the !HOTPLUG_CPU case. Reported-by: Ingo Molnar <mingo@elte.hu> Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Tested-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: benh@kernel.crashing.org LKML-Reference: <12503552312611-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* mm/init: cpu_hotplug_init() must be initialized before SLABLinus Torvalds2009-06-221-5/+0
| | | | | | | | | | | | | | | | | | SLAB uses get/put_online_cpus() which use a mutex which is itself only initialized when cpu_hotplug_init() is called. Currently we hang suring boot in SLAB due to doing that too late. Reported by James Bottomley and Sachin Sant (and possibly others). Debugged by Benjamin Herrenschmidt. This just removes the dynamic initialization of the data structures, and replaces it with a static one, avoiding this dependency entirely, and removing one unnecessary special initcall. Tested-by: Sachin Sant <sachinp@in.ibm.com> Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpu hotplug: remove unused cpuhotplug_mutex_lock()Lai Jiangshan2009-04-021-16/+0
| | | | | | | | | | | cpuhotplug_mutex_lock() is not used, remove it. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/cpu.c: create a CPU_STARTING cpu_chain notifierManfred Spraul2008-09-081-0/+1
| | | | | | | | | | | | | | | | | Right now, there is no notifier that is called on a new cpu, before the new cpu begins processing interrupts/softirqs. Various kernel function would need that notification, e.g. kvm works around by calling smp_call_function_single(), rcu polls cpu_online_map. The patch adds a CPU_STARTING notification. It also adds a helper function that sends the message to all cpu_chain handlers. Tested on x86-64. All other archs are untested. Especially on sparc, I'm not sure if I got it right. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* workqueues: make get_online_cpus() useable for work->func()Oleg Nesterov2008-07-251-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | workqueue_cpu_callback(CPU_DEAD) flushes cwq->thread under cpu_maps_update_begin(). This means that the multithreaded workqueues can't use get_online_cpus() due to the possible deadlock, very bad and very old problem. Introduce the new state, CPU_POST_DEAD, which is called after cpu_hotplug_done() but before cpu_maps_update_done(). Change workqueue_cpu_callback() to use CPU_POST_DEAD instead of CPU_DEAD. This means that create/destroy functions can't rely on get_online_cpus() any longer and should take cpu_add_remove_lock instead. [akpm@linux-foundation.org: fix CONFIG_SMP=n] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpu: fix section mismatch warnings in hotcpu_registerSam Ravnborg2008-04-291-1/+1
| | | | | | | | | | | | | | | | | | | | Fix following warnings: WARNING: vmlinux.o(.data+0x5020): Section mismatch in reference from the variable cpu_vsyscall_notifier_nb.12876 to the function .cpuinit.text:cpu_vsyscall_notifier() WARNING: vmlinux.o(.data+0x9ce0): Section mismatch in reference from the variable profile_cpu_callback_nb.17654 to the function .devinit.text:profile_cpu_callback() WARNING: vmlinux.o(.data+0xd380): Section mismatch in reference from the variable workqueue_cpu_callback_nb.15004 to the function .devinit.text:workqueue_cpu_callback() WARNING: vmlinux.o(.data+0x11d00): Section mismatch in reference from the variable relay_hotcpu_callback_nb.19626 to the function .cpuinit.text:relay_hotcpu_callback() WARNING: vmlinux.o(.data+0x12970): Section mismatch in reference from the variable cpu_callback_nb.24694 to the function .devinit.text:cpu_callback() WARNING: vmlinux.o(.data+0x3fee0): Section mismatch in reference from the variable percpu_counter_hotcpu_callback_nb.10903 to the function .cpuinit.text:percpu_counter_hotcpu_callback() WARNING: vmlinux.o(.data+0x74ce0): Section mismatch in reference from the variable topology_cpu_callback_nb.12506 to the function .cpuinit.text:topology_cpu_callback() Functions used as argument are by definition only used in HOTPLUG_CPU situations so thay are annotated __cpuinit. Annotate the static variable used by hotcpu_register with __cpuinitdata to match this definition. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include: Remove unnecessary inclusions of asm/semaphore.hMatthew Wilcox2008-04-181-1/+0
| | | | | | | | | None of these files use any of the functionality promised by asm/semaphore.h. It's possible that they (or some user of them) rely on it dragging in some unrelated header file, but I can't build all these files, so we'll have to fix any build failures as they come up. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
* cpu-hotplug: fix build on !CONFIG_SMPIngo Molnar2008-01-251-1/+7
| | | | | | fix build on !CONFIG_SMP. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()Gautham R Shenoy2008-01-251-4/+4
| | | | | | | | | | | | | | | | | Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use get_online_cpus and put_online_cpus instead as it highlights the refcount semantics in these operations. The new API guarantees protection against the cpu-hotplug operation, but it doesn't guarantee serialized access to any of the local data structures. Hence the changes needs to be reviewed. In case of pseries_add_processor/pseries_remove_processor, use cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the cpu_present_map there. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpu-hotplug: refcount based cpu hotplugGautham R Shenoy2008-01-251-0/+3
| | | | | | | | | | | | | | | | This patch implements a Refcount + Waitqueue based model for cpu-hotplug. Now, a thread which wants to prevent cpu-hotplug, will bump up a global refcount and the thread which wants to perform a cpu-hotplug operation will block till the global refcount goes to zero. The readers, if any, during an ongoing cpu-hotplug operation are blocked until the cpu-hotplug operation is over. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Paul Jackson <pj@sgi.com> [For !CONFIG_HOTPLUG_CPU ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* CPU hotplug: fix cpu_is_offline() on !CONFIG_HOTPLUG_CPUIngo Molnar2008-01-061-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | make randconfig bootup testing found that the cpufreq code crashes on bootup, if the powernow-k8 driver is enabled and if maxcpus=1 passed on the boot line to a !CONFIG_HOTPLUG_CPU kernel. First lockdep found out that there's an inconsistent unlock sequence: ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- swapper/1 is trying to release lock (&per_cpu(cpu_policy_rwsem, cpu)) at: [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 but there are no more locks to release! Call Trace: [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 [<ffffffff80251c29>] print_unlock_inbalance_bug+0x104/0x12c [<ffffffff80252f3a>] mark_held_locks+0x56/0x94 [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42 [<ffffffff807008b6>] cpufreq_add_dev+0x2a8/0x5c4 ... then shortly afterwards the cpufreq code crashed on an assert: ------------[ cut here ]------------ kernel BUG at drivers/cpufreq/cpufreq.c:1068! invalid opcode: 0000 [1] SMP [...] Call Trace: [<ffffffff805145d6>] sysdev_driver_unregister+0x5b/0x91 [<ffffffff806ff520>] cpufreq_register_driver+0x15d/0x1a2 [<ffffffff80cc0596>] powernowk8_init+0x86/0x94 [...] ---[ end trace 1e9219be2b4431de ]--- the bug was caused by maxcpus=1 bootup, which brought up the secondary core as !cpu_online() but !cpu_is_offline() either, which on on !CONFIG_HOTPLUG_CPU is always 0 (include/linux/cpu.h): /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */ static inline int cpu_is_offline(int cpu) { return 0; } but the cpufreq code uses cpu_online() and cpu_is_offline() in a mixed way - the low-level drivers use cpu_online(), while the cpufreq core uses cpu_is_offline(). This opened up the possibility to add the non-initialized sysdev device of the secondary core: cpufreq-core: trying to register driver powernow-k8 cpufreq-core: adding CPU 0 powernow-k8: BIOS error - no PSB or ACPI _PSS objects cpufreq-core: initialization failed cpufreq-core: adding CPU 1 cpufreq-core: initialization failed which then blew up. The fix is to make cpu_is_offline() always the negation of cpu_online(). With that fix applied the kernel boots up fine without crashing: Calling initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94() powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ processors (1 cpu cores) (version 2.20.00) powernow-k8: BIOS error - no PSB or ACPI _PSS objects initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94() returned -19. initcall 0xffffffff80cc0510 ran for 19 msecs: powernowk8_init+0x0/0x94() Calling initcall 0xffffffff80cc328f: init_lapic_nmi_sysfs+0x0/0x39() We could fix this by making CPU enumeration aware of max_cpus, but that would be more fragile IMO, and the cpu_online(cpu) != cpu_is_offline(cpu) possibility was quite confusing and a continuous source of bugs too. Most distributions have kernels with CPU hotplug enabled, so this bug remained hidden for a long time. Bug forensics: The broken cpu_is_offline() API variant was introduced via: commit a59d2e4e6977e7b94e003c96a41f07e96cddc340 Author: Rusty Russell <rusty@rustcorp.com.au> Date: Mon Mar 8 06:06:03 2004 -0800 [PATCH] minor cleanups for hotplug CPUs ( this predates linux-2.6.git, this commit is available from Thomas's historic git tree. ) Then 1.5 years later the cpufreq code made use of it: commit c32b6b8e524d2c337767d312814484d9289550cf Author: Ashok Raj <ashok.raj@intel.com> Date: Sun Oct 30 14:59:54 2005 -0800 [PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers + if (cpu_is_offline(cpu)) + return 0; which is a correct use of the subtly broken new API. v2.6.15 then shipped with this bug included. then it took two more years for random-kernel qa to hit it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Redefine {un}register_hotcpu_notifier() !HOTPLUG_CPU stubsSatyam Sharma2007-10-181-2/+3
| | | | | | | | | | | | | | | | | The return of the present "do {} while" based stub definition of register_hotcpu_notifier() cannot be checked. This makes the stub asymmetric w.r.t. the real HOTPLUG_CPU=y implementation that is int-returning. So let us redefine this to be consistent with the full version. Also do the same for unregister_hotcpu_notifier(). We cannot define these as static inline functions due to an existing GCC bug (#33172). So define as macros that return appropriately instead (int '0' for the register_hotcpu_notifier case and void for unregister_hotcpu_notifier). Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATIONRafael J. Wysocki2007-08-311-3/+3
| | | | | | | | | | | | Dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION introduced by commit 296699de6bdc717189a331ab6bbe90e05c94db06 "Introduce CONFIG_SUSPEND for suspend-to-Ram and standby" are incorrect, as they don't cover the facts that (1) not all architectures support suspend and (2) SMP hibernation is only possible on X86 and PPC64 (if CONFIG_PPC64_SWSUSP is set). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: make global code staticAdrian Bunk2007-08-121-2/+0
| | | | | | | | | | | | This patch makes the following needlessly global code static: - arch_reinit_sched_domains() - struct attr_sched_mc_power_savings - struct attr_sched_smt_power_savings Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* remove unused lock_cpu_hotplug_interruptible definitionNathan Lynch2007-07-161-1/+0
| | | | | | | | | | aa95387774039096c11803c04011f1aa42d85758 removed the implementation of lock_cpu_hotplug_interruptible and all users of it. This stub definition for !CONFIG_HOTPLUG_CPU was left over -- kill it now. Signed-off-by: Nathan Lynch <ntl@pobox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* <linux/sysdev.h> needs to include <linux/module.h>Ralf Baechle2007-05-081-0/+3
| | | | | | | | | | | sysdev.h uses THIS_MODULE so should include <linux/module.h>. [akpm@linux-foundation.org: couple of fixes] Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@suse.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Fix microcode-related suspend problemRafael J. Wysocki2007-04-021-0/+4
| | | | | | | | | | | | | | | | | | | | Fix the regression resulting from the recent change of suspend code ordering that causes systems based on Intel x86 CPUs using the microcode driver to hang during the resume. The problem occurs since the microcode driver uses request_firmware() in its CPU hotplug notifier, which is called after tasks has been frozen and hangs. It can be fixed by telling the microcode driver to use the microcode stored in memory during the resume instead of trying to load it from disk. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Adrian Bunk <bunk@stusta.de> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Pavel Machek <pavel@ucw.cz> Cc: Maxim <maximlevitsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if ↵Avi Kivity2007-02-121-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | !CONFIG_HOTPLUG_CPU The following patchset allows a host with running virtual machines to be suspended and, on at least a subset of the machines tested, resumed. Note that this is orthogonal to suspending and resuming an individual guest to a file. A side effect of implementing suspend/resume is that cpu hotplug is now supported. This should please the owners of big iron. This patch: KVM wants the cpu hotplug notifications, both for cpu hotplug itself, but more commonly for host suspend/resume. In order to avoid extensive #ifdefs, provide stubs when CONFIG_CPU_HOTPLUG is not defined. In all, we have four cases: - UP: register and unregister stubbed out - SMP+hotplug: full register and unregister - SMP, no hotplug, core: register as __init, unregister stubbed (cpus are brought up during core initialization) - SMP, no hotplug, module: register and unregister stubbed out (cpus cannot be brought up during module lifetime) Signed-off-by: Avi Kivity <avi@qumranet.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6Linus Torvalds2006-12-071-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (156 commits) [PATCH] x86-64: Export smp_call_function_single [PATCH] i386: Clean up smp_tune_scheduling() [PATCH] unwinder: move .eh_frame to RODATA [PATCH] unwinder: fully support linker generated .eh_frame_hdr section [PATCH] x86-64: don't use set_irq_regs() [PATCH] x86-64: check vector in setup_ioapic_dest to verify if need setup_IO_APIC_irq [PATCH] x86-64: Make ix86 default to HIGHMEM4G instead of NOHIGHMEM [PATCH] i386: replace kmalloc+memset with kzalloc [PATCH] x86-64: remove remaining pc98 code [PATCH] x86-64: remove unused variable [PATCH] x86-64: Fix constraints in atomic_add_return() [PATCH] x86-64: fix asm constraints in i386 atomic_add_return [PATCH] x86-64: Correct documentation for bzImage protocol v2.05 [PATCH] x86-64: replace kmalloc+memset with kzalloc in MTRR code [PATCH] x86-64: Fix numaq build error [PATCH] x86-64: include/asm-x86_64/cpufeature.h isn't a userspace header [PATCH] unwinder: Add debugging output to the Dwarf2 unwinder [PATCH] x86-64: Clarify error message in GART code [PATCH] x86-64: Fix interrupt race in idle callback (3rd try) [PATCH] x86-64: Remove unwind stack pointer alignment forcing again ... Fixed conflict in include/linux/uaccess.h manually Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| * [PATCH] i386: change the 'no_control' field to 'hotpluggable' in the struct cpuSiddha, Suresh B2006-12-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | Change the 'no_control' field in the cpu struct to a more positive and better term 'hotpluggable'. And change(/cleanup) the logic accordingly. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: "Li, Shaohua" <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
* | [PATCH] Handle per-subsystem mutexes for CONFIG_HOTPLUG_CPU not setGautham R Shenoy2006-12-071-2/+21
| | | | | | | | | | | | | | | | | | | | | | | | Provide a common interface for all the subsystems to lock and unlock their per-subsystem hotcpu mutexes. When CONFIG_HOTPLUG_CPU is not set, these operations would be no-ops. [akpm@osdl.org: macros -> inlines] Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] hotplug CPU: clean up hotcpu_notifier() useIngo Molnar2006-12-071-3/+3
|/ | | | | | | | | | | | | | | | | | There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn, prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus generating compiler warnings of unused symbols, hence forcing people to add #ifdefs. the compiler can skip truly unused functions just fine: text data bss dec hex filename 1624412 728710 3674856 6027978 5bfaca vmlinux.before 1624412 728710 3674856 6027978 5bfaca vmlinux.after [akpm@osdl.org: topology.c fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [POWERPC] sysfs: add support for adding/removing spu sysfs attributesChristian Krafft2006-10-251-0/+8
| | | | | | | | | | | | This patch adds two functions to create and remove sysfs attributes and attribute_group to all cpus. That allows to register sysfs attributes in a subdirectory like: /sys/devices/system/cpu/cpuX/group_name/what_ever This will be used by cbe_thermal to group all attributes dealing with thermal support in one directory. Signed-of-by: Christian Krafft <krafft@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
* [PATCH] Disable CPU hotplug during suspendRafael J. Wysocki2006-09-261-0/+8
| | | | | | | | | | | | | | | | | | | The current suspend code has to be run on one CPU, so we use the CPU hotplug to take the non-boot CPUs offline on SMP machines. However, we should also make sure that these CPUs will not be enabled by someone else after we have disabled them. The functions disable_nonboot_cpus() and enable_nonboot_cpus() are moved to kernel/cpu.c, because they now refer to some stuff in there that should better be static. Also it's better if disable_nonboot_cpus() returns an error instead of panicking if something goes wrong, and enable_nonboot_cpus() has no reason to panic(), because the CPUs may have been enabled by the userland before it tries to take them online. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* cpu hotplug: simplify and hopefully fix lockingLinus Torvalds2006-07-231-6/+0
| | | | | | | | | | | | | | | | | The CPU hotplug locking was quite messy, with a recursive lock to handle the fact that both the actual up/down sequence wanted to protect itself from being re-entered, but the callbacks that it called also tended to want to protect themselves from CPU events. This splits the lock into two (one to serialize the whole hotplug sequence, the other to protect against the CPU present bitmaps changing). The latter still allows recursive usage because some subsystems (ondemand policy for cpufreq at least) had already gotten too used to the lax locking, but the locking mistakes are hopefully now less fundamental, and we now warn about recursive lock usage when we see it, in the hope that it can be fixed. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hotcpu_notifier-fixesAndrew Morton2006-07-011-3/+3
| | | | | | | | | Always use do {} while (0). Failing to do so can cause subtle compile failures or bugs. Cc: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: add hotplug versions of cpu_notifierChandra Seetharaman2006-06-271-0/+4
| | | | | | | | | | | Define new macros register_hotcpu_notifier() and unregister_hotcpu_notifier() that redefines register_cpu_notifier() and unregister_cpu_notifier() for use only when HOTPLUG_CPU is defined. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: make [un]register_cpu_notifier init time onlyChandra Seetharaman2006-06-271-0/+6
| | | | | | | | | | | | | | | | CPUs come online only at init time (unless CONFIG_HOTPLUG_CPU is defined). So, cpu_notifier functionality need to be available only at init time. This patch makes register_cpu_notifier() available only at init time, unless CONFIG_HOTPLUG_CPU is defined. This patch exports register_cpu_notifier() and unregister_cpu_notifier() only if CONFIG_HOTPLUG_CPU is defined. Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Cc: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] node hotplug: register cpu: remove node structKAMEZAWA Hiroyuki2006-06-271-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With Goto-san's patch, we can add new pgdat/node at runtime. I'm now considering node-hot-add with cpu + memory on ACPI. I found acpi container, which describes node, could evaluate cpu before memory. This means cpu-hot-add occurs before memory hot add. In most part, cpu-hot-add doesn't depend on node hot add. But register_cpu(), which creates symbolic link from node to cpu, requires that node should be onlined before register_cpu(). When a node is onlined, its pgdat should be there. This patch-set holds off creating symbolic link from node to cpu until node is onlined. This removes node arguments from register_cpu(). Now, register_cpu() requires 'struct node' as its argument. But the array of struct node is now unified in driver/base/node.c now (By Goto's node hotplug patch). We can get struct node in generic way. So, this argument is not necessary now. This patch also guarantees add cpu under node only when node is onlined. It is necessary for node-hot-add vs. cpu-hot-add patch following this. Moreover, register_cpu calculates cpu->node_id by cpu_to_node() without regard to its 'struct node *root' argument. This patch removes it. Also modify callers of register_cpu()/unregister_cpu, whose args are changed by register-cpu-remove-node-struct patch. [Brice.Goglin@ens-lyon.org: fix it] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Check if cpu can be onlined before calling smp_prepare_cpu()Ashok Raj2006-03-251-1/+0
| | | | | | | | | | | | | | | | | | - Moved check for online cpu out of smp_prepare_cpu() - Moved default declaration of smp_prepare_cpu() to kernel/cpu.c - Removed lock_cpu_hotplug() from smp_prepare_cpu() to around it, since its called from cpu_up() as well now. - Removed clearing from cpu_present_map during cpu_offline as it breaks using cpu_up() directly during a subsequent online operation. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: "Li, Shaohua" <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] get_cpu_sysdev() signedness fixAndrew Morton2006-03-201-1/+1
| | | | | | | Doing (int < NR_CPUS) doesn't dtrt if it's negative.. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [PATCH] clean up lock_cpu_hotplug() in cpufreqAshok Raj2005-11-281-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are some callers in cpufreq hotplug notify path that the lowest function calls lock_cpu_hotplug(). The lock is already held during cpu_up() and cpu_down() calls when the notify calls are broadcast to registered clients. Ideally if possible, we could disable_preempt() at the highest caller and make sure we dont sleep in the path down in cpufreq->driver_target() calls but the calls are so intertwined and cumbersome to cleanup. Hence we consistently use lock_cpu_hotplug() and unlock_cpu_hotplug() in all places. - Removed export of cpucontrol semaphore and made it static. - removed explicit uses of up/down with lock_cpu_hotplug() so we can keep track of the the callers in same thread context and just keep refcounts without calling a down() that causes a deadlock. - Removed current_in_hotplug() uses - Removed PF_HOTPLUG_CPU in sched.h introduced for the current_in_hotplug() temporary workaround. Tested with insmod of cpufreq_stat.ko, and logical online/offline to make sure we dont have any hang situations. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: Zwane Mwaikambo <zwane@linuxpower.ca> Cc: Shaohua Li <shaohua.li@intel.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpu hotplug: fix locking in cpufreq driversAshok Raj2005-11-091-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | When calling target drivers to set frequency, we take cpucontrol lock. When we modified the code to accomodate CPU hotplug, there was an attempt to take a double lock of cpucontrol leading to a deadlock. Since the current thread context is already holding the cpucontrol lock, we dont need to make another attempt to acquire it. Now we leave a trace in current->flags indicating current thread already is under cpucontrol lock held, so we dont attempt to do this another time. Thanks to Andrew Morton for the beating:-) From: Brice Goglin <Brice.Goglin@ens-lyon.org> Build fix (akpm: this patch is still unpleasant. Ashok continues to look for a cleaner solution, doesn't he? ;)) Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] introduce get_cpu_sysdev() to retrieve a sysfs entry for a cpu.Ashok Raj2005-10-301-0/+1
| | | | | | | | | | | | | | | | | | | | | Some modules creating sysfs entries under /sys/devices/system/cpu/cpuX/ need to know the parent sysfs entry to make devices under them. This will just return the sysfs entry for a given cpu. sysfs entries showing under each cpu sysfs can be easily created if such entries can be created by registering a sysfs driver for cpuclass. The issue is when the entry is created the CPU may not be online, hence we would need to defer the creation until the online notification comes. Current users: cache entries for Intel CPU's and cpufreq subsystem. Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Zwane Mwaikambo <zwane@holomorphy.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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