Re: [Xen-devel] [PATCH v5 3/6] x86 / pv: do not treat PGC_extra pages as RAM

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: 10 March 2020 15:13
> To: paul@xxxxxxx
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx; 'Paul Durrant' <pdurrant@xxxxxxxxxx>; 
> 'Andrew Cooper'
> <andrew.cooper3@xxxxxxxxxx>; 'Wei Liu' <wl@xxxxxxx>; 'Roger Pau Monné' 
> <roger.pau@xxxxxxxxxx>
> Subject: Re: [PATCH v5 3/6] x86 / pv: do not treat PGC_extra pages as RAM
> 
> On 10.03.2020 16:05, Paul Durrant wrote:
> >> -----Original Message-----
> >> From: Jan Beulich <jbeulich@xxxxxxxx>
> >> Sent: 10 March 2020 14:59
> >>
> >> In reply to patch 6 I did suggest to
> >> have a separate list, but without taking these pages off
> >> d->page_list,
> >
> > How would that work without adding an extra page_list_entry into struct 
> > page_info?
> 
> As said there, it'd be a singly linked list using a __pdx_t
> field just like there already is with "next_shadow", i.e.
> you'd add another union member "next_extra" or some such. Of
> course the list shouldn't grow too long, or else insertion
> and removal may become a bottleneck. Not sure how well this
> would fit Arm, though; maybe they wouldn't need this, but
> that depends on whether the list would be used for purposes
> beyond dumping.
> 

That seems more obscure and bug-prone than an extra list head in struct domain. 
I'd really prefer to stick with that even if it does make things a little more 
ugly until xenpage_list goes away.

  Paul


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel