From: Andrew Morton <akpm@linux-foundation.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>, Peter Xu <peterx@redhat.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v3 0/2] s390/mm: shared zeropage + KVM fixes
Date: Thu, 11 Apr 2024 14:28:27 -0700 [thread overview]
Message-ID: <20240411142827.d5c3bc401c6536bb1315049a@linux-foundation.org> (raw)
In-Reply-To: <20240411161441.910170-1-david@redhat.com>
On Thu, 11 Apr 2024 18:14:39 +0200 David Hildenbrand <david@redhat.com> wrote:
> This series fixes one issue with uffd + shared zeropages on s390x and
> fixes that "ordinary" KVM guests can make use of shared zeropages again.
>
> ...
>
> Without the shared zeropage, during (2), the VM would suddenly consume
> 100 GiB on the migration source and destination. On the migration source,
> where we don't excpect memory overcommit, we could easilt end up crashing
> the VM during migration.
>
> Independent of that, memory handed back to the hypervisor using "free page
> reporting" would end up consuming actual memory after the migration on the
> destination, not getting freed up until reused+freed again.
>
Is a backport desirable?
If so, the [1/2] Fixes dates back to 2015 and the [2/2] Fixes is from
2017. Is it appropriate that the patches be backported so far back,
and into different kernel versions?
next prev parent reply other threads:[~2024-04-11 21:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-11 16:14 David Hildenbrand
2024-04-11 16:14 ` [PATCH v3 1/2] mm/userfaultfd: don't place zeropages when zeropages are disallowed David Hildenbrand
2024-04-11 16:14 ` [PATCH v3 2/2] s390/mm: re-enable the shared zeropage for !PV and !skeys KVM guests David Hildenbrand
2024-04-11 16:37 ` Alexander Gordeev
2024-04-11 21:09 ` David Hildenbrand
2024-04-15 11:49 ` Christian Borntraeger
2024-04-15 13:14 ` Alexander Gordeev
2024-04-15 18:24 ` Alexander Gordeev
2024-04-15 19:14 ` David Hildenbrand
2024-04-16 6:37 ` Alexander Gordeev
2024-04-16 7:05 ` David Hildenbrand
2024-04-16 12:02 ` Christian Borntraeger
2024-04-16 13:41 ` David Hildenbrand
2024-04-18 13:09 ` Christian Borntraeger
2024-04-11 21:28 ` Andrew Morton [this message]
2024-04-11 21:56 ` [PATCH v3 0/2] s390/mm: shared zeropage + KVM fixes David Hildenbrand
2024-04-12 13:25 ` Alexander Gordeev
2024-04-17 12:46 ` Alexander Gordeev
2024-04-17 12:47 ` David Hildenbrand
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