lkml.org 
[lkml]   [2018]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap
On Wed, Sep 26, 2018 at 11:25:37AM -0700, Alexander Duyck wrote:
> With that said I am open to suggestions if you still feel like I need to
> follow this up with some additional work. I just want to avoid introducing
> any regressions in regards to functionality or performance.

Hi Alexander,

the problem I see is that devm/hmm is using some of the memory-hotplug
features, but their paths are becoming more and more diverged with changes
like this, and that is sometimes a problem when we need to change
something in the generic memory-hotplug code.

E.g: I am trying to fix two issues in the memory-hotplug where we can
access steal pages if we hot-remove memory before online it.
That was not so difficult to fix, but I really struggled with the exceptions
that HMM/devm represent in this regard, for instance, regarding the resources.

The RFCv2 can be found here [1] https://patchwork.kernel.org/patch/10569083/
And the initial discussion with Jerome Glisse can be found here [2].

So it would be great to stick to the memory-hotplug path as much as possible,
otherwise when a problem arises, we need to think how we can workaround
HMM/devm.

[1] https://patchwork.kernel.org/patch/10569083/
[2] https://patchwork.kernel.org/patch/10558725/

--
Oscar Salvador
SUSE L3

\
 
 \ /
  Last update: 2018-09-27 14:33    [W:0.150 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site