Messages in this thread | | | Date | Mon, 12 Sep 2016 18:05:07 +1000 | From | Nicholas Piggin <> | Subject | Re: DAX mapping detection (was: Re: [PATCH] Fix region lost in /proc/self/smaps) |
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On Mon, 12 Sep 2016 00:51:28 -0700 Christoph Hellwig <hch@infradead.org> wrote:
> On Mon, Sep 12, 2016 at 05:25:15PM +1000, Oliver O'Halloran wrote: > > What are the problems here? Is this a matter of existing filesystems > > being unable/unwilling to support this or is it just fundamentally > > broken? > > It's a fundamentally broken model. See Dave's post that actually was > sent slightly earlier then mine for the list of required items, which > is fairly unrealistic. You could probably try to architect a file > system for it, but I doubt it would gain much traction.
It's not fundamentally broken, it just doesn't fit well existing filesystems.
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.
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