Re: [BUG?] numa required on x86_64?

From: Randy Dunlap
Date: Fri Jun 24 2011 - 18:23:44 EST


On Sat, 25 Jun 2011 00:00:58 +0200 Ian Kumlien wrote:

> Hi all,
>
> Just found this when wanting to play with development kernels again.
> Since there is no -gitXX snapshots anymore, I cloned the git =)...
>
> But, it failed to build properly with my config:
>
> mm/page_cgroup.c line 308: node_start_pfn and node_end_pfn is only
> defined under NUMA on x86_64.
>
> The commit that changed the use of this was introduced recently while
> the mmzone_64.h hasn't been changed since april.

You should have cc-ed the commit Author (I did so).

> commit 37573e8c718277103f61f03741bdc5606d31b07e
> Author: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Date: Wed Jun 15 15:08:42 2011 -0700
>
> memcg: fix init_page_cgroup nid with sparsemem
>
> Commit 21a3c9646873 ("memcg: allocate memory cgroup structures in local
> nodes") makes page_cgroup allocation as NUMA aware. But that caused a
> problem https://bugzilla.kernel.org/show_bug.cgi?id=36192.
>
> The problem was getting a NID from invalid struct pages, which was not
> initialized because it was out-of-node, out of [node_start_pfn,
> node_end_pfn)
>
> Now, with sparsemem, page_cgroup_init scans pfn from 0 to max_pfn. But
> this may scan a pfn which is not on any node and can access memmap which
> is not initialized.
>
> This makes page_cgroup_init() for SPARSEMEM node aware and remove a code
> to get nid from page->flags. (Then, we'll use valid NID always.)
>
> [akpm@xxxxxxxxxxxxxxxxxxxx: try to fix up comments]
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

A patch for this has been posted at least 2 times.
It's here: http://marc.info/?l=linux-mm&m=130827204306775&w=2

Andrew, please merge this (^that^) patch.

---
~Randy
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