From: Christoph Hellwig <hch@infradead.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Oliver O'Halloran <oohall@gmail.com>,
Yumei Huang <yuhuang@redhat.com>, Michal Hocko <mhocko@suse.com>,
Xiao Guangrong <guangrong.xiao@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
KVM list <kvm@vger.kernel.org>, Linux MM <linux-mm@kvack.org>,
Gleb Natapov <gleb@kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
mtosatti@redhat.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: DAX mapping detection (was: Re: [PATCH] Fix region lost in /proc/self/smaps)
Date: Mon, 12 Sep 2016 08:01:48 -0700 [thread overview]
Message-ID: <20160912150148.GA10039@infradead.org> (raw)
In-Reply-To: <20160912180507.533b3549@roar.ozlabs.ibm.com>
On Mon, Sep 12, 2016 at 06:05:07PM +1000, Nicholas Piggin wrote:
> It's not fundamentally broken, it just doesn't fit well existing
> filesystems.
Or the existing file system architecture for that matter. Which makes
it a fundamentally broken model.
> Dave's post of requirements is also wrong. A filesystem does not have
> to guarantee all that, it only has to guarantee that is the case for
> a given block after it has a mapping and page fault returns, other
> operations can be supported by invalidating mappings, etc.
Which doesn't really matter if your use case is manipulating
fully mapped files.
But back to the point: if you want to use a full blown Linux or Unix
filesystem you will always have to fsync (or variants of it like msync),
period.
If you want a volume manager on stereoids that hands out large chunks
of storage memory that can't ever be moved, truncated, shared, allocated
on demand, etc - implement it in your library on top of a device file.
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next prev parent reply other threads:[~2016-09-12 15:01 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
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 [this message]
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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