From: Dan Williams <dan.j.williams@intel.com>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, Gleb Natapov <gleb@kernel.org>,
mtosatti@redhat.com, KVM list <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Stefan Hajnoczi <stefanha@redhat.com>,
Yumei Huang <yuhuang@redhat.com>, Linux MM <linux-mm@kvack.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: DAX mapping detection (was: Re: [PATCH] Fix region lost in /proc/self/smaps)
Date: Fri, 9 Sep 2016 08:40:29 -0700 [thread overview]
Message-ID: <CAPcyv4ibiZG3SkW0TZywn8Qovo3hpxBqs4wCfw1DFEbbE=1-Mg@mail.gmail.com> (raw)
In-Reply-To: <5d5ef209-e005-12c6-9b34-1fdd21e1e6e2@linux.intel.com>
On Fri, Sep 9, 2016 at 1:55 AM, Xiao Guangrong
<guangrong.xiao@linux.intel.com> wrote:
[..]
>>
>> Whether a persistent memory mapping requires an msync/fsync is a
>> filesystem specific question. This mincore proposal is separate from
>> that. Consider device-DAX for volatile memory or mincore() called on
>> an anonymous memory range. In those cases persistence and filesystem
>> metadata are not in the picture, but it would still be useful for
>> userspace to know "is there page cache backing this mapping?" or "what
>> is the TLB geometry of this mapping?".
>
>
> I got a question about msync/fsync which is beyond the topic of this thread
> :)
>
> Whether msync/fsync can make data persistent depends on ADR feature on
> memory
> controller, if it exists everything works well, otherwise, we need to have
> another
> interface that is why 'Flush hint table' in ACPI comes in. 'Flush hint
> table' is
> particularly useful for nvdimm virtualization if we use normal memory to
> emulate
> nvdimm with data persistent characteristic (the data will be flushed to a
> persistent storage, e.g, disk).
>
> Does current PMEM programming model fully supports 'Flush hint table'? Is
> userspace allowed to use these addresses?
If you publish flush hint addresses in the virtual NFIT the guest VM
will write to them whenever a REQ_FLUSH or REQ_FUA request is sent to
the virtual /dev/pmemX device. Yes, seems straightforward to take a
VM exit on those events and flush simulated pmem to persistent
storage.
next prev parent reply other threads:[~2016-09-09 15:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-08 4:32 DAX mapping detection (was: Re: [PATCH] Fix region lost in /proc/self/smaps) Dan Williams
2016-09-08 22:56 ` Ross Zwisler
2016-09-08 23:04 ` Dan Williams
2016-09-09 8:55 ` Xiao Guangrong
2016-09-09 15:40 ` Dan Williams [this message]
2016-09-12 6:00 ` Xiao Guangrong
2016-09-12 3:44 ` Rudoff, Andy
2016-09-12 6:31 ` Xiao Guangrong
2016-09-12 1:40 ` Dave Chinner
2016-09-15 5:55 ` Darrick J. Wong
2016-09-15 6:25 ` Dave Chinner
2016-09-12 5:27 ` Christoph Hellwig
2016-09-12 7:25 ` Oliver O'Halloran
2016-09-12 7:51 ` Christoph Hellwig
2016-09-12 8:05 ` Nicholas Piggin
2016-09-12 15:01 ` Christoph Hellwig
2016-09-13 1:31 ` Nicholas Piggin
2016-09-13 4:06 ` Dan Williams
2016-09-13 5:40 ` Nicholas Piggin
2016-09-12 21:34 ` Dave Chinner
2016-09-13 1:53 ` Nicholas Piggin
2016-09-13 7:17 ` Christoph Hellwig
2016-09-13 9:06 ` Nicholas Piggin
2016-09-14 7:39 ` Dave Chinner
2016-09-14 10:19 ` Nicholas Piggin
2016-09-15 2:31 ` Dave Chinner
2016-09-15 3:49 ` Nicholas Piggin
2016-09-15 10:32 ` Dave Chinner
2016-09-15 11:42 ` Nicholas Piggin
2016-09-15 22:33 ` Dave Chinner
2016-09-16 5:54 ` Nicholas Piggin
2016-12-19 21:11 ` Ross Zwisler
2016-12-20 1:09 ` Darrick J. Wong
2016-12-20 1:18 ` Dan Williams
2016-12-21 0:40 ` Darrick J. Wong
2016-12-21 16:53 ` Dan Williams
2016-12-21 21:24 ` Dave Chinner
2016-12-21 21:33 ` Dan Williams
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