Re: [PATCH part5 0/7] Arrange hotpluggable memory as ZONE_MOVABLE.

[Yinghai Lu <yinghai@kernel.org>]

On Thu, Aug 15, 2013 at 12:06 PM, Toshi Kani <toshi.kani@hp.com> wrote:
> On Wed, 2013-08-14 at 09:22 +0800, Tang Chen wrote:
>> On 08/14/2013 06:33 AM, Yinghai Lu wrote:
>> ......
>> >
>> >>     relocate_initrd()
>> >
>> > size could be very big, like several hundreds mega bytes.
>> > should be anywhere, but will be freed after booting.
>> >
>> > ===>  so we should not limit it to near kernel range.
>> >
>> >>     acpi_initrd_override()
>> >
>> > should be 64 * 10 about 1M.
>> >
>> >>     reserve_crashkernel()
>> >
>> > could be under 4G, or above 4G.
>> > size could be 512M or 8G whatever.
>> >
>> > looks like
>> > should move down relocated_initrd and reserve_crashkernel.
>>
>> OK, will try to do this.
>>
>> Thank you for the explanation. :)
>
> So, we still need reordering, and put a new requirement that all earlier
> allocations must be small...
>
> I think the root of this issue is that ACPI init point is not early
> enough in the boot sequence.  If it were much earlier already, the whole
> thing would have been very simple.  We are now trying to workaround this
> issue in the mblock code (which itself is a fine idea), but this ACPI
> issue still remains and similar issues may come up again in future.
>
> For instance, ACPI SCPR/DBGP/DBG2 tables allow the OS to initialize
> serial console/debug ports at early boot time.  The earlier it can be
> initialized, the better this feature will be.  These tables are not
> currently used by Linux due to a licensing issue, but it could be
> addressed some time soon.  As platforms becoming more complex & legacy
> free, the needs of ACPI tables will increase.
>
> I think moving up the ACPI init point earlier is a good direction.

Good point.

If we put acpi_initrd_override in BRK, and can more acpi_boot_table_init()
much early.

Yinghai

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