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.
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WARNING: multiple messages have this Message-ID (diff)
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.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: David Hildenbrand <david@redhat.com>
Cc: virtio-dev@lists.oasis-open.org, linux-hyperv@vger.kernel.org,
Michal Hocko <mhocko@suse.com>, Baoquan He <bhe@redhat.com>,
linux-acpi@vger.kernel.org, Wei Yang <richard.weiyang@gmail.com>,
linux-s390@vger.kernel.org, linux-nvdimm@lists.01.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, linux-mm@kvack.org,
"Michael S . Tsirkin" <mst@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
xen-devel@lists.xenproject.org, Michal Hocko <mhocko@kernel.org>,
linuxppc-dev@lists.ozlabs.org
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.
next prev parent reply other threads:[~2020-04-30 22:24 UTC|newest]
Thread overview: 121+ 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 ` [virtio-dev] " David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` 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 ` [virtio-dev] " David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` [PATCH v2 2/3] mm/memory_hotplug: Introduce MHP_NO_FIRMWARE_MEMMAP David Hildenbrand
2020-04-30 10:29 ` [virtio-dev] " David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 15:38 ` Eric W. Biederman
2020-04-30 15:38 ` Eric W. Biederman
2020-04-30 15:38 ` Eric W. Biederman
2020-04-30 15:38 ` Eric W. Biederman
2020-04-30 15:52 ` David Hildenbrand
2020-04-30 15:52 ` [virtio-dev] " David Hildenbrand
2020-04-30 15:52 ` David Hildenbrand
2020-04-30 15:52 ` David Hildenbrand
2020-04-30 16:04 ` Dave Hansen
2020-04-30 16:04 ` Dave Hansen
2020-04-30 16:04 ` Dave Hansen
2020-04-30 16:33 ` Eric W. Biederman
2020-04-30 16:33 ` Eric W. Biederman
2020-04-30 16:33 ` Eric W. Biederman
2020-04-30 16:33 ` Eric W. Biederman
2020-04-30 16:49 ` David Hildenbrand
2020-04-30 16:49 ` [virtio-dev] " David Hildenbrand
2020-04-30 16:49 ` David Hildenbrand
2020-04-30 16:49 ` David Hildenbrand
2020-04-30 18:06 ` Eric W. Biederman
2020-04-30 18:06 ` Eric W. Biederman
2020-04-30 18:06 ` Eric W. Biederman
2020-04-30 18:06 ` Eric W. Biederman
2020-04-30 18:43 ` David Hildenbrand
2020-04-30 18:43 ` [virtio-dev] " David Hildenbrand
2020-04-30 18:43 ` David Hildenbrand
2020-04-30 18:43 ` David Hildenbrand
2020-04-30 18:58 ` Dan Williams
2020-04-30 18:58 ` Dan Williams
2020-04-30 18:58 ` Dan Williams
2020-04-30 18:58 ` Dan Williams
2020-04-30 22:24 ` Andrew Morton [this message]
2020-04-30 22:24 ` Andrew Morton
2020-04-30 22:24 ` Andrew Morton
2020-05-01 9:34 ` David Hildenbrand
2020-05-01 9:34 ` [virtio-dev] " David Hildenbrand
2020-05-01 9:34 ` David Hildenbrand
2020-05-01 9:34 ` David Hildenbrand
2020-05-01 16:56 ` Dan Williams
2020-05-01 16:56 ` Dan Williams
2020-05-01 16:56 ` Dan Williams
2020-05-01 16:56 ` Dan Williams
2020-05-01 17:21 ` David Hildenbrand
2020-05-01 17:21 ` [virtio-dev] " David Hildenbrand
2020-05-01 17:21 ` David Hildenbrand
2020-05-01 17:21 ` David Hildenbrand
2020-05-01 17:39 ` Dan Williams
2020-05-01 17:39 ` Dan Williams
2020-05-01 17:39 ` Dan Williams
2020-05-01 17:39 ` Dan Williams
2020-05-01 17:45 ` David Hildenbrand
2020-05-01 17:45 ` [virtio-dev] " David Hildenbrand
2020-05-01 17:45 ` David Hildenbrand
2020-05-01 17:45 ` David Hildenbrand
2020-05-01 17:51 ` David Hildenbrand
2020-05-01 17:51 ` [virtio-dev] " David Hildenbrand
2020-05-01 17:51 ` David Hildenbrand
2020-05-01 17:51 ` David Hildenbrand
2020-05-01 18:03 ` Dan Williams
2020-05-01 18:03 ` Dan Williams
2020-05-01 18:03 ` Dan Williams
2020-05-01 18:03 ` Dan Williams
2020-05-01 18:14 ` David Hildenbrand
2020-05-01 18:14 ` [virtio-dev] " David Hildenbrand
2020-05-01 18:14 ` David Hildenbrand
2020-05-01 18:14 ` David Hildenbrand
2020-05-01 18:43 ` Dan Williams
2020-05-01 18:43 ` Dan Williams
2020-05-01 18:43 ` Dan Williams
2020-05-01 18:43 ` Dan Williams
2020-05-01 19:17 ` David Hildenbrand
2020-05-01 19:17 ` [virtio-dev] " David Hildenbrand
2020-05-01 19:17 ` David Hildenbrand
2020-05-01 19:17 ` David Hildenbrand
2020-05-01 20:12 ` Dan Williams
2020-05-01 20:12 ` Dan Williams
2020-05-01 20:12 ` Dan Williams
2020-05-01 20:12 ` Dan Williams
2020-05-01 21:10 ` David Hildenbrand
2020-05-01 21:10 ` [virtio-dev] " David Hildenbrand
2020-05-01 21:10 ` David Hildenbrand
2020-05-01 21:10 ` David Hildenbrand
2020-05-01 21:52 ` Dan Williams
2020-05-01 21:52 ` Dan Williams
2020-05-01 21:52 ` Dan Williams
2020-05-01 21:52 ` Dan Williams
2020-05-02 9:26 ` David Hildenbrand
2020-05-02 9:26 ` [virtio-dev] " David Hildenbrand
2020-05-02 9:26 ` David Hildenbrand
2020-05-02 9:26 ` David Hildenbrand
2020-05-02 18:03 ` Dan Williams
2020-05-02 18:03 ` Dan Williams
2020-05-02 18:03 ` Dan Williams
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 10:29 ` [virtio-dev] " David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 10:29 ` David Hildenbrand
2020-04-30 11:23 ` Dave Hansen
2020-04-30 11:23 ` Dave Hansen
2020-04-30 11:23 ` Dave Hansen
2020-04-30 15:28 ` David Hildenbrand
2020-04-30 15:28 ` [virtio-dev] " David Hildenbrand
2020-04-30 15:28 ` David Hildenbrand
2020-04-30 15:28 ` David Hildenbrand
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