From: Michael Ellerman <mpe@ellerman•id.au>
To: Nathan Fontenot <nfont@linux•vnet.ibm.com>,
linuxppc-dev@lists•ozlabs.org
Cc: Vitaly Kuznetsov <vkuznets@redhat•com>,
Andrew Morton <akpm@linux-foundation•org>
Subject: Re: [PATCH] powerpc/pseries: Auto online hotplugged memory
Date: Fri, 24 Jun 2016 15:35:47 +1000 [thread overview]
Message-ID: <1466746547.11831.2.camel@ellerman.id.au> (raw)
In-Reply-To: <5768A2EB.5030808@linux.vnet.ibm.com>
On Mon, 2016-06-20 at 21:14 -0500, Nathan Fontenot wrote:
> On 06/20/2016 07:57 PM, Michael Ellerman wrote:
> > On Mon, 2016-06-20 at 08:51 -0500, Nathan Fontenot wrote:
> >
> > > Auto online hotplugged memory
> > >
> > > A recent update (commit id 31bc3858ea3) to the core mm hotplug code
> > > introduced the memhp_auto_online variable to allow for automatically
> > > onlining memory that is added.
> > >
> > > This patch update the pseries memory hotplug code to enable this so that
> > > any memory DLPAR added to the system is automatically onlined. The code
> > > to add the memory block for memory added from add_memory() is removed as
> > > this is not needed, the memory_add code does this.
> >
> > Is this a bug fix, or just a cleanup?
>
> Hmmm.. some cleanup and some new feature. The removal of the memblock_add()
> call is a cleanup and the setting of the memhp_auto_online variable is
> taking advantage of a feature I was not previously aware of.
OK. Looking at usage of memhp_auto_online it's not clear to me that you're
supposed to be setting it in arch code.
eg. if I build my kernel with CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n, I will
expect it to not be onlined by default.
Similarly if I boot with memhp_default_state=offline on the kernel command line.
But this patch would then mean it is onlined by default. So that seems kind of
confusing for users.
I think instead we should be merging the bulk of this patch, but without the
forced assignment to memhp_auto_online?
cheers
next prev parent reply other threads:[~2016-06-24 5:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 13:51 [PATCH] powerpc/pseries: Auto online hotplugged memory Nathan Fontenot
2016-06-21 0:57 ` Michael Ellerman
2016-06-21 2:14 ` Nathan Fontenot
2016-06-24 5:35 ` Michael Ellerman [this message]
2016-06-27 14:41 ` Nathan Fontenot
2016-06-28 3:46 ` Michael Ellerman
2016-06-28 16:31 ` Nathan Fontenot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1466746547.11831.2.camel@ellerman.id.au \
--to=mpe@ellerman$(echo .)id.au \
--cc=akpm@linux-foundation$(echo .)org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=nfont@linux$(echo .)vnet.ibm.com \
--cc=vkuznets@redhat$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox