Messages in this thread | | | Date | Mon, 16 Mar 2009 09:48:02 +0100 | From | Ingo Molnar <> | Subject | Re: [PULL] x86 cpumask work |
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* Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Sunday 15 March 2009 16:30:44 Ingo Molnar wrote: > > > > > } else if (check_c1e_idle(c)) { > > > printk(KERN_INFO "using C1E aware idle routine\n"); > > > - alloc_cpumask_var(&c1e_mask, GFP_KERNEL); > > > - cpumask_clear(c1e_mask); > > > + /* c1e_mask can only be NULL during boot of first cpu. */ > > > + if (c1e_mask == NULL) { > > > + alloc_cpumask_var(&c1e_mask, GFP_KERNEL); > > > > Sigh, there are two bugs here: > > > > 1) what if the GFP_KERNEL allocation fails? > > As the comments says, it can only be NULL during boot of the first CPU. > > start_kernel -> check_bugs -> identify_boot_cpu -> identify_cpu > -> select_idle_routine. > > Did you want me to panic if it fails?
Ah, ok. But i think it's very unobvious to embedd a "once per bootup" dynamic allocation like that. Please put it into a separate init routine instead. That way select_idle() [which runs during every CPU hotplug event] wont have this allocation.
Ingo
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