Re: [Xen-devel] ACPI fixmap overflow

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 11/15/2016 03:44 PM, Andrew Cooper wrote:
> On 15/11/2016 20:39, Boris Ostrovsky wrote:
>> On 11/15/2016 02:45 PM, Andrew Cooper wrote:
>>> On 15/11/16 19:34, Boris Ostrovsky wrote:
>>>> In addition to running out of e820 entries on that large machine that
>>>> Alex was referring to in [0] he is also running out of ACPI fixmap space
>>>> while parsing MADT (the box has *lots* of processors). The
>>>> quick-and-dirty solution is to increase NUM_FIXMAP_ACPI_PAGES but I
>>>> wonder whether we should move to dynamic memory allocation.
>>> Why do we use fixmap anyway?  It doesn't look too hard to reorder
>>> vm_init() slightly higher, and be able to use ioremap() for all APCI tables.
>> Hmm... Let me see how possible this is. Just moving it up won't work
>> since heap allocator is initialized after ACPI tables.
> We have plenty of usable PTEs already allocated at boot, mainly from the
> init pagetables.  Given a static __init vm_bitmap, a new boot-time-only
> vm range should be usable without any heap allocations at all.

Wouldn't that (using pre-allocated PTEs), in a way, be equivalent to
increasing fixmap size?

-boris

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