Messages in this thread | | | Date | Fri, 17 Jan 2003 00:56:32 -0500 (EST) | From | Zwane Mwaikambo <> | Subject | Re: [PATCH][2.5] smp_call_function_mask |
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On Thu, 16 Jan 2003, Andrew Morton wrote:
> Zwane Mwaikambo <zwane@holomorphy.com> wrote: > > > > This patch adds a smp_call_function which also accepts a cpu mask which is > > needed for targetting specific or groups of cpus. > > What is it needed for?
I need to interrupt a specific cpu to initiate a cpu offline process.
> > Index: linux-2.5.58-cpu_hotplug/arch/i386/kernel/smp.c > > ia32 only?
I'll try my best with the other archs. I can hack and rediff.
> > +int smp_call_function_mask (void (*func) (void *info), void *info, int nonatomic, > > + int wait, unsigned long mask) > > +/* > > + * [SUMMARY] Run a function on specific CPUs, save self. > > + * <func> The function to run. This must be fast and non-blocking. > > + * <info> An arbitrary pointer to pass to the function. > > + * <nonatomic> currently unused. > > + * <wait> If true, wait (atomically) until function has completed on other CPUs. > > + * <mask> The bitmask of CPUs to call the function > > + * [RETURNS] 0 on success, else a negative status code. Does not return until > > + * remote CPUs are nearly ready to execute <<func>> or are or have executed. > > + * > > + * You must not call this function with disabled interrupts or from a > > + * hardware interrupt handler or from a bottom half handler. > > + */ > > Please don't invent new coding styles. The comment block goes outside the > function. Nice comment block though.
No credit to me, ripped from smp_call_function, i'll switch to docbook version.
> > +{ > > + struct call_data_struct data; > > + int num_cpus = hweight32(mask); > > + > > + if (num_cpus == 0) > > + return -EINVAL; > > + > > + if ((1UL << smp_processor_id()) & mask) > > + return -EINVAL; > > Preempt safety?
Good point, i think a get_cpu and put_cpu_no_resched should suffice.
Zwane -- function.linuxpower.ca
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