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path: root/drivers/oprofile/nmi_timer_int.c
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2016-12-02oprofile/nmi timer: Convert to hotplug state machineSebastian Andrzej Siewior
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: oprofile-list@lists.sf.net Cc: Robert Richter <rric@kernel.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161126231350.10321-6-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-03-20oprofile, nmi-timer: Fix CPU hotplug callback registrationSrivatsa S. Bhat
Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the nmi-timer code in oprofile by using this latter form of callback registration. Cc: Robert Richter <rric@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2011-11-04oprofile, x86: Reimplement nmi timer mode using perf eventRobert Richter
The legacy x86 nmi watchdog code was removed with the implementation of the perf based nmi watchdog. This broke Oprofile's nmi timer mode. To run nmi timer mode we relied on a continuous ticking nmi source which the nmi watchdog provided. The nmi tick was no longer available and current watchdog can not be used anymore since it runs with very long periods in the range of seconds. This patch reimplements the nmi timer mode using a perf counter nmi source. V2: * removing pr_info() * fix undefined reference to `__udivdi3' for 32 bit build * fix section mismatch of .cpuinit.data:nmi_timer_cpu_nb * removed nmi timer setup in arch/x86 * implemented function stubs for op_nmi_init/exit() * made code more readable in oprofile_init() V3: * fix architectural initialization in oprofile_init() * fix CONFIG_OPROFILE_NMI_TIMER dependencies Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Robert Richter <robert.richter@amd.com>