From: Oscar Salvador <osalvador@suse.de>
To: Michal Hocko <mhocko@suse.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
akpm@linux-foundation.org, David Hildenbrand <david@redhat.com>,
rafael@kernel.org, nathanl@linux.ibm.com, cheloha@linux.ibm.com,
stable@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: don't rely on system state to detect hot-plug operations
Date: Thu, 10 Sep 2020 15:39:00 +0200 [thread overview]
Message-ID: <20200910133854.GA8713@linux> (raw)
In-Reply-To: <20200910124847.GH28354@dhcp22.suse.cz>
On Thu, Sep 10, 2020 at 02:48:47PM +0200, Michal Hocko wrote:
> > Is there any actual usecase for a configuration like this? What is the
> > point to statically define additional memory like this when the same can
> > be achieved on the same command line?
Well, for qemu I am not sure, but if David is right, it seems you can face
the same if you reboot a vm with hotplugged memory.
Moreover, it seems that the problem we spotted with [1], it was a VM running on
Promox (KVM).
The Hypervisor probably said at boot time "Ey, I do have these ACPI devices, care
to enable them now"?
As always, there are all sorts of configurations/scenarios out there in the wild.
> Forgot to ask one more thing. Who is going to online that memory when
> userspace is not running yet?
Depends, if you have CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE set or you specify
memhp_default_online_type=[online,online_*], memory will get onlined right
after hot-adding stage:
/* online pages if requested */
if (memhp_default_online_type != MMOP_OFFLINE)
walk_memory_blocks(start, size, NULL, online_memory_block);
If not, systemd-udev will do the magic once the system is up.
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2020-09-10 13:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5cbd92e1-c00a-4253-0119-c872bfa0f2bc@redhat.com>
2020-09-08 17:08 ` [PATCH] mm: don't rely on system state to detect hot-plug operations Laurent Dufour
2020-09-08 17:31 ` Greg Kroah-Hartman
2020-09-08 17:40 ` David Hildenbrand
2020-09-09 8:26 ` Laurent Dufour
2020-09-09 8:31 ` David Hildenbrand
2020-09-09 9:35 ` Laurent Dufour
2020-09-09 6:56 ` Laurent Dufour
2020-09-09 7:40 ` Michal Hocko
2020-09-09 7:48 ` Laurent Dufour
2020-09-09 9:09 ` Michal Hocko
2020-09-09 9:21 ` Laurent Dufour
2020-09-09 9:24 ` David Hildenbrand
2020-09-09 9:32 ` Laurent Dufour
2020-09-09 12:30 ` Greg Kroah-Hartman
2020-09-09 12:32 ` David Hildenbrand
2020-09-09 12:36 ` Greg Kroah-Hartman
2020-09-09 12:45 ` Michal Hocko
2020-09-09 10:59 ` Michal Hocko
2020-09-09 16:07 ` Laurent Dufour
2020-09-10 7:23 ` Michal Hocko
2020-09-10 7:51 ` Laurent Dufour
2020-09-10 11:12 ` Michal Hocko
2020-09-10 11:35 ` Laurent Dufour
2020-09-10 12:00 ` David Hildenbrand
2020-09-10 12:36 ` Laurent Dufour
2020-09-10 12:38 ` David Hildenbrand
2020-09-10 12:01 ` Michal Hocko
2020-09-10 12:03 ` Oscar Salvador
2020-09-10 12:32 ` Laurent Dufour
2020-09-10 12:47 ` Michal Hocko
2020-09-10 12:48 ` Michal Hocko
2020-09-10 13:39 ` Oscar Salvador [this message]
2020-09-10 13:51 ` Michal Hocko
2020-09-10 14:40 ` Michal Hocko
2020-09-10 12:49 ` David Hildenbrand
2020-09-10 13:54 ` Michal Hocko
2020-09-10 13:57 ` David Hildenbrand
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=20200910133854.GA8713@linux \
--to=osalvador@suse.de \
--cc=akpm@linux-foundation.org \
--cc=cheloha@linux.ibm.com \
--cc=david@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=ldufour@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=nathanl@linux.ibm.com \
--cc=rafael@kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.