Re: [patch 1/2] x86, fpu: split FPU state from task struct - v5

From: Alexey Dobriyan
Date: Tue Mar 11 2008 - 06:09:35 EST


On 3/11/08, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
>
> > > - extern void __bad_fxsave_alignment(void);
> > > -
> > > - if (offsetof(struct task_struct, thread.i387.fxsave) & 15)
> > > - __bad_fxsave_alignment();
> >
> > I think removal of such checks needs giving necessary alignment to
> > cache. Previously it worked because of __aligned((16)) and
> > L1_CACHE_SHIFT combo.
>
> it's still checked, just elsewhere:
>
> > + WARN_ON((unsigned long)dst->thread.xstate & 15);
>
> i'd not expect us to ever align worse than 16 bytes in the future

But sysfs tells me alignment of "xstate" is 8 now. Object size is 512 which
is masking it.
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