lkml.org 
[lkml]   [2007]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 06/26] Xen-paravirt_ops: paravirt_ops: allocate a fixmap slot
Jeremy Fitzhardinge wrote:
> Ingo Molnar wrote:
>
>> why not vmalloc it on the guest side? fixmaps are bad for this purpose
>> for a general paravirt implementation, it limits the size of the shared
>> info page, etc.
>>
>
> Yes. vmalloc would have the annoying side-effect of actually allocating
> some pages which would be shadowed by the remapping, but I guess
> get_vm_area would do the job. I'll give it a go.

Hm, this is a bit awkward. We need to map the shared info page fairly
early - say, around paging_init - but we're still on the bootmem
allocator at that point, so get_vm_area isn't usable yet. Using a
fixmap keeps things simple. It seems to me that having a single fixmap
available is useful for this kind of simple/early mapping, and if
someone needs to map something larger, then they can put it off until
get_vm_area() is available...

J
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-28 01:53    [W:0.089 / U:1.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site