Messages in this thread | | | Date | Wed, 18 Jan 2012 06:42:50 -0800 | From | Greg KH <> | Subject | Re: [PATCH] mce: fix warning messages about static struct mce_device |
| |
On Wed, Jan 18, 2012 at 10:31:38AM +0100, Ingo Molnar wrote: > > * Greg KH <gregkh@suse.de> wrote: > > > On Tue, Jan 17, 2012 at 09:38:43AM +0100, Ingo Molnar wrote: > > > > > > * Greg KH <gregkh@suse.de> wrote: > > > > > > > diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h > > > > index f35ce43..6aefb14 100644 > > > > --- a/arch/x86/include/asm/mce.h > > > > +++ b/arch/x86/include/asm/mce.h > > > > @@ -151,7 +151,7 @@ static inline void enable_p5_mce(void) {} > > > > > > > > void mce_setup(struct mce *m); > > > > void mce_log(struct mce *m); > > > > -DECLARE_PER_CPU(struct device, mce_device); > > > > +extern struct device *mce_device[CONFIG_NR_CPUS]; > > > > > > Minor nit, i don't think we have any other such [CONFIG_NR_CPUS] > > > pattern in the kernel. > > > > > > This should be something like: > > > > > > DECLARE_PER_CPU(struct device *, mce_device); > > > > That is what we used to have, but with just a static struct > > device. [...] > > Which was fine in itself for a per CPU data structure - wouldnt > the warning be fixed by memset()-ing before registering the > device or such, if device registry absolutely needs a pre-zeroed > buffer?
It was already fixed that way, but the problem is that you can not have statically allocated 'struct device' objects in the system. That's what my add-on patch fixed, also resolving the syslog messages saying there was no release function for the device as well.
> I still think there must be some bug/assumption lurking in the > device layer - do you require all device allocations to be one > via zalloc()? Seems like a weird and unrobust requirement.
Yes, that's always been the requirement.
> I don't object to the quick fix that gets rid of the warnings, > but that quick fix came at the price of leaving the real bug > unfixed and at the price of introducing a new ugliness ;-)
Nope, all of the bugs are now fixed :)
> > [...] We really don't need this to be in the per-cpu area, a > > flat array should be just fine, why can't we use the > > CONFIG_NR_CPUS value? Should we use something else? > > By that argument we don't really need PER_CPU() areas to begin > with, a flat [CONFIG_NR_CPUS] array is just fine, right?
I never said that, only for this type of variable.
> Amongst other things we use PER_CPU to have an array of just 2 > elements on a dual core system, even if it boots a > CONFIG_NR_CPUS=512 distro kernel. That saves RAM, and with > higher CONFIG_NR_CPUS values it adds up quickly. > > > > Or the pointer should be attached to the CPU info structure. > > > > Ok, I have no objection to that, do you want me to make a > > patch doing that, now that this is already in Linus's tree? > > Would be nice if you could do that or some other equivalent > solution, i'd really not like to see the [CONFIG_NR_CPUS] > pattern to spread in the kernel, we spent a lot of time getting > rid of such uses ;-)
Ok, I'll work on resolving this.
thanks,
greg k-h
| |