From: Dave Hansen <dave.hansen@intel.com>
To: 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>,
Paolo Bonzini <pbonzini@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH 2/4] mm: introduce new VM_NOZEROPAGE flag
Date: Sat, 18 Oct 2014 09:28:17 -0700 [thread overview]
Message-ID: <54429521.80402@intel.com> (raw)
In-Reply-To: <20141018164928.2341415f@BR9TG4T3.de.ibm.com>
On 10/18/2014 07:49 AM, Dominik Dingel wrote:
> On Fri, 17 Oct 2014 15:04:21 -0700
> Dave Hansen <dave.hansen@intel.com> wrote:
>> Is there ever a time where the VMAs under an mm have mixed VM_NOZEROPAGE
>> status? Reading the patches, it _looks_ like it might be an all or
>> nothing thing.
>
> 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.
>> Full disclosure: I've got an x86-specific feature I want to steal a flag
>> for. Maybe we should just define another VM_ARCH bit.
>>
>
> So you think of something like:
>
> #if defined(CONFIG_S390)
> # define VM_NOZEROPAGE VM_ARCH_1
> #endif
>
> #ifndef VM_NOZEROPAGE
> # define VM_NOZEROPAGE VM_NONE
> #endif
>
> right?
Yeah, something like that.
next prev parent reply other threads:[~2014-10-18 16:28 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 [this message]
2014-10-20 18:14 ` Paolo Bonzini
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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