linux-hyperv.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: David Hildenbrand <david@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	virtio-dev@lists.oasis-open.org,
	virtualization@lists.linux-foundation.org,
	linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-hyperv@vger.kernel.org,
	linux-s390@vger.kernel.org, xen-devel@lists.xenproject.org,
	Michal Hocko <mhocko@kernel.org>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Michal Hocko <mhocko@suse.com>,
	Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
	Wei Yang <richard.weiyang@gmail.com>, Baoquan He <bhe@redhat.com>
Subject: Re: [PATCH v2 2/3] mm/memory_hotplug: Introduce MHP_NO_FIRMWARE_MEMMAP
Date: Thu, 30 Apr 2020 15:24:03 -0700	[thread overview]
Message-ID: <20200430152403.e0d6da5eb1cad06411ac6d46@linux-foundation.org> (raw)
In-Reply-To: <b28c9e02-8cf2-33ae-646b-fe50a185738e@redhat.com>

On Thu, 30 Apr 2020 20:43:39 +0200 David Hildenbrand <david@redhat.com> wrote:

> > 
> > Why does the firmware map support hotplug entries?
> 
> I assume:
> 
> The firmware memmap was added primarily for x86-64 kexec (and still, is
> mostly used on x86-64 only IIRC). There, we had ACPI hotplug. When DIMMs
> get hotplugged on real HW, they get added to e820. Same applies to
> memory added via HyperV balloon (unless memory is unplugged via
> ballooning and you reboot ... the the e820 is changed as well). I assume
> we wanted to be able to reflect that, to make kexec look like a real reboot.
> 
> This worked for a while. Then came dax/kmem. Now comes virtio-mem.
> 
> 
> But I assume only Andrew can enlighten us.
> 
> @Andrew, any guidance here? Should we really add all memory to the
> firmware memmap, even if this contradicts with the existing
> documentation? (especially, if the actual firmware memmap will *not*
> contain that memory after a reboot)

For some reason that patch is misattributed - it was authored by
Shaohui Zheng <shaohui.zheng@intel.com>, who hasn't been heard from in
a decade.  I looked through the email discussion from that time and I'm
not seeing anything useful.  But I wasn't able to locate Dave Hansen's
review comments.



  parent reply	other threads:[~2020-04-30 22:24 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 10:29 [PATCH v2 0/3] mm/memory_hotplug: Allow to not create firmware memmap entries David Hildenbrand
2020-04-30 10:29 ` [PATCH v2 1/3] mm/memory_hotplug: Prepare passing flags to add_memory() and friends David Hildenbrand
2020-04-30 10:29 ` [PATCH v2 2/3] mm/memory_hotplug: Introduce MHP_NO_FIRMWARE_MEMMAP David Hildenbrand
2020-04-30 15:38   ` Eric W. Biederman
2020-04-30 15:52     ` David Hildenbrand
2020-04-30 16:04       ` Dave Hansen
2020-04-30 16:33       ` Eric W. Biederman
2020-04-30 16:49         ` David Hildenbrand
2020-04-30 18:06           ` Eric W. Biederman
2020-04-30 18:43             ` David Hildenbrand
2020-04-30 18:58               ` Dan Williams
2020-04-30 22:24               ` Andrew Morton [this message]
2020-05-01  9:34                 ` David Hildenbrand
2020-05-01 16:56                   ` Dan Williams
2020-05-01 17:21                     ` David Hildenbrand
2020-05-01 17:39                       ` Dan Williams
2020-05-01 17:45                         ` David Hildenbrand
2020-05-01 17:51                           ` David Hildenbrand
2020-05-01 18:03                             ` Dan Williams
2020-05-01 18:14                               ` David Hildenbrand
2020-05-01 18:43                                 ` Dan Williams
2020-05-01 19:17                                   ` David Hildenbrand
2020-05-01 20:12                                     ` Dan Williams
2020-05-01 21:10                                       ` David Hildenbrand
2020-05-01 21:52                                         ` Dan Williams
2020-05-02  9:26                                           ` David Hildenbrand
2020-05-02 18:03                                             ` Dan Williams
2020-04-30 10:29 ` [PATCH v2 3/3] device-dax: Add system ram (add_memory()) with MHP_NO_FIRMWARE_MEMMAP David Hildenbrand
2020-04-30 11:23   ` Dave Hansen
2020-04-30 15:28     ` 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=20200430152403.e0d6da5eb1cad06411ac6d46@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=bhe@redhat.com \
    --cc=david@redhat.com \
    --cc=ebiederm@xmission.com \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-hyperv@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mhocko@kernel.org \
    --cc=mhocko@suse.com \
    --cc=mst@redhat.com \
    --cc=pankaj.gupta.linux@gmail.com \
    --cc=richard.weiyang@gmail.com \
    --cc=virtio-dev@lists.oasis-open.org \
    --cc=virtualization@lists.linux-foundation.org \
    --cc=xen-devel@lists.xenproject.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).