lkml.org 
[lkml]   [2013]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Bug fix PATCH 2/2] acpi, movablemem_map: Make whatever nodes the kernel resides in un-hotpluggable.
On 02/20/2013 05:00:56 AM, Tang Chen wrote:
> There could be several memory ranges in the node in which the kernel
> resides.
> When using movablemem_map=acpi, we may skip one range that have
> memory reserved
> by memblock. But if it is too small, then the kernel will fail to
> boot. So, make
> the whole node which the kernel resides in un-hotpluggable. Then the
> kernel has
> enough memory to use.
>
> Reported-by: H Peter Anvin <hpa@zytor.com>
> Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>

Docs part Acked-by: Rob Landley <rob@landley.net> (with minor
non-blocking snark).

> @@ -1673,6 +1675,10 @@ bytes respectively. Such letter suffixes can
> also be entirely omitted.
> satisfied. So the administrator should be
> careful that
> the amount of movablemem_map areas are not too
> large.
> Otherwise kernel won't have enough memory to
> start.
> + NOTE: We don't stop users specifying the node
> the
> + kernel resides in as hotpluggable so that
> this
> + option can be used as a workaround of
> firmware
> + bugs.

I usually see workaround "for", not "of". And your whitespace is
inconsistent on that last line.

And I'm now kind of curious what such a workaround would accomplish,
but I'm suspect it's obvious to people who wind up needing it.

> MTD_Partition= [MTD]
> Format: <name>,<region-number>,<size>,<offset>
> diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
> index b8028b2..79836d0 100644
> --- a/arch/x86/mm/srat.c
> +++ b/arch/x86/mm/srat.c
> @@ -166,6 +166,9 @@ handle_movablemem(int node, u64 start, u64 end,
> u32 hotpluggable)
> * for other purposes, such as for kernel image. We cannot
> prevent
> * kernel from using these memory, so we need to exclude these
> memory
> * even if it is hotpluggable.
> + * Furthermore, to ensure the kernel has enough memory to boot,
> we make
> + * all the memory on the node which the kernel resides in
> + * un-hotpluggable.
> */

Can you hot-unplug half a node? (Do you have a choice with the
granularity here?)

Rob


\
 
 \ /
  Last update: 2013-02-23 23:01    [W:0.084 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site