From: Paolo Bonzini <pbonzini@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>,
Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Mel Gorman <mgorman@suse.de>,
Michal Hocko <mhocko@suse.cz>, Rik van Riel <riel@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Bob Liu <lliubbo@gmail.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>,
Gleb Natapov <gleb@kernel.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@kernel.org>,
Jianyu Zhan <nasa4836@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Konstantin Weitz <konstantin.weitz@gmail.com>,
kvm@vger.kernel.org, linux390@de.ibm.com,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH 2/4] mm: introduce new VM_NOZEROPAGE flag
Date: Mon, 20 Oct 2014 20:14:53 +0200 [thread overview]
Message-ID: <5445511D.1090603@redhat.com> (raw)
In-Reply-To: <54429521.80402@intel.com>
On 10/18/2014 06:28 PM, Dave Hansen wrote:
> > Currently it is an all or nothing thing, but for a future change we might want to just
> > tag the guest memory instead of the complete user address space.
>
> I think it's a bad idea to reserve a flag for potential future use. If
> you_need_ it in the future, let's have the discussion then. For now, I
> think it should probably just be stored in the mm somewhere.
I agree with Dave (I thought I disagreed, but I changed my mind while
writing down my thoughts). Just define mm_forbids_zeropage in
arch/s390/include/asm, and make it return mm->context.use_skey---with a
comment explaining how this is only for processes that use KVM, and then
only for guests that use storage keys.
Paolo (who was just taught what storage keys really are)
next prev parent reply other threads:[~2014-10-20 18:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-17 14:09 [PATCH 0/4] mm: new flag to forbid zero page mappings for a vma Dominik Dingel
2014-10-17 14:09 ` [PATCH 1/4] s390/mm: recfactor global pgste updates Dominik Dingel
2014-10-17 14:09 ` [PATCH 2/4] mm: introduce new VM_NOZEROPAGE flag Dominik Dingel
2014-10-17 22:04 ` Dave Hansen
2014-10-18 14:49 ` Dominik Dingel
2014-10-18 16:28 ` Dave Hansen
2014-10-20 18:14 ` Paolo Bonzini [this message]
2014-10-21 6:11 ` Martin Schwidefsky
2014-10-21 8:11 ` Paolo Bonzini
2014-10-21 11:20 ` Dominik Dingel
2014-10-17 14:09 ` [PATCH 3/4] s390/mm: prevent and break zero page mappings in case of storage keys Dominik Dingel
2014-10-17 14:09 ` [PATCH 4/4] s390/mm: disable KSM for storage key enabled pages Dominik Dingel
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