Re: [PATCH] memory hotplug: Correct page reservation checking

From: Nathan Fontenot
Date: Tue Oct 04 2011 - 10:19:30 EST

On 10/03/2011 07:50 PM, Andrew Morton wrote:
> On Mon, 26 Sep 2011 10:22:33 -0500
> Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote:
>> The check to ensure that pages of recently added memory sections are correctly
>> marked as reserved before trying to online the memory is broken. The request
>> to online the memory fails with the following:
>> kernel: section number XXX page number 256 not reserved, was it already online?
>> This updates the page reservation checking to check the pages of each memory
>> section of the memory block being onlined individually.
> Why was this only noticed now? Is there something unusual about the
> way in which you're using it, or has nobody ever used this code, or...?

As far as I know it is only the powerpc/pseries code that uses the feature that
allows memory blocks in sysfs to span multiple memory sections. We do this
because on pseries memory add/remove is done on a per LMB basis and we can have
machine where an LMB spans multiple memory sections.

This was just noticed due to a lack of testing between the 2.6.38/39 kernels where
this feature originally went in and the current mainline kernel.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at