From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Baoquan He <bhe@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org,
Yumei Huang <yuhuang@redhat.com>,
Igor Mammedov <imammedo@redhat.com>,
Eduardo Habkost <ehabkost@redhat.com>,
Milan Zamazal <mzamazal@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Haiyang Zhang <haiyangz@microsoft.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Michal Hocko <mhocko@kernel.org>, Michal Hocko <mhocko@suse.com>,
Oscar Salvador <osalvador@suse.de>,
Paul Mackerras <paulus@samba.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Wei Yang <richard.weiyang@gmail.com>
Subject: Re: [PATCH v2 0/8] mm/memory_hotplug: allow to specify a default online_type
Date: Wed, 18 Mar 2020 16:00:15 +0100 [thread overview]
Message-ID: <874kul3dz4.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20200318144119.GD30899@MiWiFi-R3L-srv>
Baoquan He <bhe@redhat.com> writes:
> Is there a reason hyperV need boot with small memory, then enlarge it
> with huge memory? Since it's a real case in hyperV, I guess there must
> be reason, I am just curious.
>
It doesn't really *need* to but this can be utilized in e.g. 'hot
standby' schemes I believe. Also, it may be enough if the administrator
is just trying to e.g. double the size of RAM but the VM is already
under memory pressure. I wouldn't say that these cases are common but
afair bugs like 'I tried adding more memory to my VM and it just OOMed'
were reported in the past.
--
Vitaly
WARNING: multiple messages have this Message-ID (diff)
From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Baoquan He <bhe@redhat.com>
Cc: Yumei Huang <yuhuang@redhat.com>,
linux-hyperv@vger.kernel.org, Michal Hocko <mhocko@suse.com>,
David Hildenbrand <david@redhat.com>,
Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, Paul Mackerras <paulus@samba.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Eduardo Habkost <ehabkost@redhat.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Wei Yang <richard.weiyang@gmail.com>,
Oscar Salvador <osalvador@suse.de>,
Milan Zamazal <mzamazal@redhat.com>,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Igor Mammedov <imammedo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 0/8] mm/memory_hotplug: allow to specify a default online_type
Date: Wed, 18 Mar 2020 16:00:15 +0100 [thread overview]
Message-ID: <874kul3dz4.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20200318144119.GD30899@MiWiFi-R3L-srv>
Baoquan He <bhe@redhat.com> writes:
> Is there a reason hyperV need boot with small memory, then enlarge it
> with huge memory? Since it's a real case in hyperV, I guess there must
> be reason, I am just curious.
>
It doesn't really *need* to but this can be utilized in e.g. 'hot
standby' schemes I believe. Also, it may be enough if the administrator
is just trying to e.g. double the size of RAM but the VM is already
under memory pressure. I wouldn't say that these cases are common but
afair bugs like 'I tried adding more memory to my VM and it just OOMed'
were reported in the past.
--
Vitaly
next prev parent reply other threads:[~2020-03-18 15:00 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-17 10:49 [PATCH v2 0/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:49 ` [PATCH v2 1/8] drivers/base/memory: rename MMOP_ONLINE_KEEP to MMOP_ONLINE David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:49 ` [PATCH v2 2/8] drivers/base/memory: map MMOP_OFFLINE to 0 David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:49 ` [PATCH v2 3/8] drivers/base/memory: store mapping between MMOP_* and string in an array David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:49 ` [PATCH v2 4/8] powernv/memtrace: always online added memory blocks David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:58 ` Michal Hocko
2020-03-17 10:58 ` Michal Hocko
2020-03-17 22:04 ` Wei Yang
2020-03-17 22:04 ` Wei Yang
2020-03-19 9:49 ` Michael Ellerman
2020-03-19 9:49 ` Michael Ellerman
2020-03-17 10:49 ` [PATCH v2 5/8] hv_balloon: don't check for memhp_auto_online manually David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 16:29 ` Vitaly Kuznetsov
2020-03-17 16:29 ` Vitaly Kuznetsov
2020-03-17 16:33 ` David Hildenbrand
2020-03-17 16:33 ` David Hildenbrand
2020-03-17 18:46 ` David Hildenbrand
2020-03-17 18:46 ` David Hildenbrand
2020-03-17 10:49 ` [PATCH v2 6/8] mm/memory_hotplug: unexport memhp_auto_online David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 10:59 ` Michal Hocko
2020-03-17 10:59 ` Michal Hocko
2020-03-17 22:24 ` Wei Yang
2020-03-17 22:24 ` Wei Yang
2020-03-17 10:49 ` [PATCH v2 7/8] mm/memory_hotplug: convert memhp_auto_online to store an online_type David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 11:00 ` Michal Hocko
2020-03-17 11:00 ` Michal Hocko
2020-03-17 10:49 ` [PATCH v2 8/8] mm/memory_hotplug: allow to specify a default online_type David Hildenbrand
2020-03-17 10:49 ` David Hildenbrand
2020-03-17 11:01 ` Michal Hocko
2020-03-17 11:01 ` Michal Hocko
2020-03-17 11:05 ` David Hildenbrand
2020-03-17 11:05 ` David Hildenbrand
2020-03-17 11:08 ` David Hildenbrand
2020-03-17 11:08 ` David Hildenbrand
2020-03-18 13:05 ` [PATCH v2 0/8] " Baoquan He
2020-03-18 13:05 ` Baoquan He
2020-03-18 13:50 ` David Hildenbrand
2020-03-18 13:50 ` David Hildenbrand
2020-03-18 14:50 ` Baoquan He
2020-03-18 14:50 ` Baoquan He
2020-03-18 13:54 ` Michal Hocko
2020-03-18 13:54 ` Michal Hocko
2020-03-18 14:41 ` Baoquan He
2020-03-18 14:41 ` Baoquan He
2020-03-18 13:58 ` Vitaly Kuznetsov
2020-03-18 13:58 ` Vitaly Kuznetsov
2020-03-18 14:41 ` Baoquan He
2020-03-18 14:41 ` Baoquan He
2020-03-18 15:00 ` Vitaly Kuznetsov [this message]
2020-03-18 15:00 ` Vitaly Kuznetsov
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