RE: [PATCH v5 2/3] x86, mpx: hook #BR exception handler to allocate bound tables

[Ren, Qiaowei]

> -----Original Message-----
> From: H. Peter Anvin [mailto:hpa@xxxxxxxxx]
> Sent: Tuesday, February 25, 2014 1:52 AM
> To: Hansen, Dave; Ren, Qiaowei; Thomas Gleixner; Ingo Molnar
> Cc: x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 2/3] x86, mpx: hook #BR exception handler to allocate
> bound tables
> 
> On 02/24/2014 09:27 AM, Dave Hansen wrote:
> >
> > Can you talk a little bit about what the design is here?  Why does the
> > kernel have to do the allocation of the virtual address space?  Does
> > it really need to MAP_POPULATE?  bt_size looks like 4MB, and that's an
> > awful lot of memory to eat up at once.  Shouldn't we just let the
> > kernel demand-fault this like everything else?
> >
> 
> MAP_POPULATE definitely seems like the wrong thing.
> 
Oh. This option should be removed.

Thanks,
Qiaowei
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