Re: [Xen-devel] [PATCH v10 09/25] x86: refactor psr: L3 CAT: set value: implement framework.

[Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>]

On 17-04-13 05:31:41, Jan Beulich wrote:
> >>> On 13.04.17 at 13:11, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> > On 17-04-13 04:58:06, Jan Beulich wrote:
> >> >>> On 13.04.17 at 12:49, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> >> > How about a per socket array like this:
> >> > uint32_t domain_switch[1024];
> >> > 
> >> > Every bit represents a domain id. Then, we can handle this case as below:
> >> > 1. In 'psr_cpu_init()', clear the array to be 0. I think this place is 
> >> > enough to
> >> >    cover socket offline case. We do not need to clear it in 
> >> > 'free_socket_resources'.
> >> > 
> >> > 2. In 'psr_ctxt_switch_to()', test_and_set_bit(domain_id, domain_switch) 
> >> > to set
> >> >    the bit to 1 according to domain_id. If the old value is 0 and the 
> >> >    'psr_cos_ids[socket]' is not 0, restore 'psr_cos_ids[socket]' to be 0.
> >> > 
> >> > 3. In 'psr_set_val()', test_and_set_bit(domain_id, domain_switch) to set 
> >> > the bit
> >> >    to 1 too. Then, update 'psr_cos_ids[socket]' according to find/pick 
> >> > flow.
> >> > 
> >> > Then, we only use 4KB for one socket.
> >> 
> >> This looks to come closer to something I'd consider acceptable, but
> >> I may not understand your intentions in full yet: For one, there's
> >> nowhere you clear the bit (other than presumably during socket
> >> cleanup). 
> > 
> > Actually, clear the array in 'free_socket_resources' has same effect. I can
> > move clear action into it.
> 
> That wasn't my point - I was asking about clearing individual bits.
> Point being that if you only ever set bits in the map, you'll likely
> end up iterating through all active domains anyway.
> 
If entering 'free_socket_resources', that means no more actions to
the array on this socket except clearing it. Can I just memset this array
of the socekt to 0?

> Jan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel