Re: [patch -mm4] i386: __init should be __cpuinit

From: Pavel Machek
Date: Thu Feb 02 2006 - 16:33:35 EST


Hi!

> > When CONFIG_HOTPLUG_CPU on i386 there are places where __init[data] is
> > referenced from normal code.
> >
> > On startup:
> > arch/i386/kernel/cpu/amd.c::amd_init_cpu():
> > cpu_devs[X86_VENDOR_AMD] = &amd_cpu_dev;
> > amd_cpu_dev is declared __initdata and is freed
> >
> > On CPU hotplug:
> > arch/i386/kernel/cpu/common.c::get_cpu_vendor():
> > for (i = 0; i < X86_VENDOR_NUM; i++) {
> > if (cpu_devs[i]) {
> > if (!strcmp(v,cpu_devs[i]->c_ident[0]) ||
> >
> > To fix this, change every instance of __init that seems suspicious
> > into __cpuinit. When !CONFIG_HOTPLUG_CPU there is no change in .text
> > or .data size. When enabled, .text += 3248 bytes; .data += 2148 bytes.
> >
> > This should be safe in every case; the only drawback is the extra code and
> > data when CPU hotplug is enabled.
>
> Especially as for the bulk of them, those CPUs aren't hotplug capable.
> (I seriously doubt we'll ever see a hotplugable cyrix for eg, which
> takes up the bulk of your diff).
>
> How about leaving it __init on non-hotplug systems, and somehow removing
> those from cpu_devs, so get_cpu_vendor() just skips them ?
> NULL'ing those entries should be just a few bytes, instead of adding 5KB.

We use cpu hotplug system for swsusp; but unless someone makes
cyrix/SMP machine and tries to suspend it, we are ok.

Pavel
--
Thanks, Sharp!
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