Re: [Xen-devel] [PATCH v7 03/14] x86: detect and initialize Intel CAT feature

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 19.05.15 at 10:42, <JBeulich@xxxxxxxx> wrote:
>>>> On 19.05.15 at 09:40, <chao.p.peng@xxxxxxxxxxxxxxx> wrote:
>> On Mon, May 18, 2015 at 02:33:51PM +0100, Jan Beulich wrote:
>>> >>> On 08.05.15 at 10:56, <chao.p.peng@xxxxxxxxxxxxxxx> wrote:
>>> > --- a/xen/arch/x86/psr.c
>>> > +++ b/xen/arch/x86/psr.c
>>> > @@ -19,14 +19,26 @@
>>> >  #include <asm/psr.h>
>>> >  
>>> >  #define PSR_CMT        (1<<0)
>>> > +#define PSR_CAT        (1<<1)
>>> > +
>>> > +struct psr_cat_socket_info {
>>> > +    unsigned int cbm_len;
>>> > +    unsigned int cos_max;
>>> > +};
>>> >  
>>> >  struct psr_assoc {
>>> >      uint64_t val;
>>> >  };
>>> >  
>>> >  struct psr_cmt *__read_mostly psr_cmt;
>>> > +
>>> > +static unsigned long *__read_mostly cat_socket_init_bitmap;
>>> > +static unsigned long *__read_mostly cat_socket_enable_bitmap;
>>> 
>>> Didn't we agree to fold these two into one? Apart from that the
>>> _bitmap name tag doesn't seem very useful...
>> 
>> Looks like this?
>> 
>> static unsigned long *__read_mostly cat_socket_init,
>>                      *__read_mostly cat_socket_enable;
> 
> Yes, except that you will want to drop one (or make clear why you
> need both).
> 
>>> >  static int cpu_callback(
>>> >      struct notifier_block *nfb, unsigned long action, void *hcpu)
>>> >  {
>>> >      if ( action == CPU_STARTING )
>>> >          psr_cpu_init();
>>> > +    else if ( action == CPU_DYING )
>>> > +        psr_cpu_fini();
>>> 
>>> Are these the right notifiers for doing things involving memory
>>> allocation / freeing?
>> 
>> psr_cpu_fini() does not really have memory allocation/freeing but
>> psr_cpu_init() does have.
> 
> Hmm, wait - where did I see this allocation? Looking again, I don't see
> it now. But if there was one, then surely it would be wrong for _fini
> to not free it.

Ah, it's actually patch 4 where an allocation gets added. So
adjustments seem to be needed there.

Jan


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