5c2aed6225
-allow stop_mahcine_run() to call a function on all cpus. Calling stop_machine_run() with a 'ALL_CPUS' invokes this new behavior. stop_machine_run() proceeds as normal until the calling cpu has invoked 'fn'. Then, we tell all the other cpus to call 'fn'. Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> CC: Adrian Bunk <bunk@stusta.de> CC: Andi Kleen <andi@firstfloor.org> CC: Alexey Dobriyan <adobriyan@gmail.com> CC: Christoph Hellwig <hch@infradead.org> CC: mingo@elte.hu CC: akpm@osdl.org
58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
#ifndef _LINUX_STOP_MACHINE
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#define _LINUX_STOP_MACHINE
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/* "Bogolock": stop the entire machine, disable interrupts. This is a
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very heavy lock, which is equivalent to grabbing every spinlock
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(and more). So the "read" side to such a lock is anything which
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diables preeempt. */
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#include <linux/cpu.h>
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#include <asm/system.h>
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#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
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#define ALL_CPUS ~0U
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/**
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* stop_machine_run: freeze the machine on all CPUs and run this function
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* @fn: the function to run
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* @data: the data ptr for the @fn()
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* @cpu: if @cpu == n, run @fn() on cpu n
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* if @cpu == NR_CPUS, run @fn() on any cpu
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* if @cpu == ALL_CPUS, run @fn() first on the calling cpu, and then
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* concurrently on all the other cpus
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*
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* Description: This causes a thread to be scheduled on every other cpu,
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* each of which disables interrupts, and finally interrupts are disabled
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* on the current CPU. The result is that noone is holding a spinlock
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* or inside any other preempt-disabled region when @fn() runs.
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*
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* This can be thought of as a very heavy write lock, equivalent to
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* grabbing every spinlock in the kernel. */
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int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
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/**
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* __stop_machine_run: freeze the machine on all CPUs and run this function
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* @fn: the function to run
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* @data: the data ptr for the @fn
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* @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
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*
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* Description: This is a special version of the above, which returns the
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* thread which has run @fn(): kthread_stop will return the return value
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* of @fn(). Used by hotplug cpu.
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*/
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struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
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unsigned int cpu);
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#else
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static inline int stop_machine_run(int (*fn)(void *), void *data,
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unsigned int cpu)
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{
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int ret;
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local_irq_disable();
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ret = fn(data);
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local_irq_enable();
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return ret;
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}
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#endif /* CONFIG_SMP */
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#endif /* _LINUX_STOP_MACHINE */
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