Re: [PATCH 3/3] compcache documentation

[Andrew Morton]

On Sat, 21 Mar 2009 18:01:40 +0530 Nitin Gupta <nitingupta910@xxxxxxxxx> wrote:

> Andrew Morton wrote:
> > On Fri, 20 Mar 2009 19:44:08 +0530 Nitin Gupta <ngupta@xxxxxxxxxx> wrote:
> > 
> >> ...
> >>
> >> +   backing_dev: This is block device to be used as backing store for compcache.
> >> +	It must be a valid swap partition. We move data to this device when we
> >> +	encounter incompressible page or memlimit is reached. TODO: we may also
> >> +	move some pages from compcache to this device in case system is really
> >> +	low on memory.
> >> +	This device is not directly visible to kernel as a swap device
> >> +	(/proc/swaps will only show /dev/ramzswap0 and not this device).
> >> +	Managing this backing device is the job of compcache module.
> > 
> > hrm, OK, it kinda/sorta/maybe might be a little bit like a "compressed
> > cache".  But if someone comes up with a real compressed cache (ie:
> > pagecache) then they'll want their name back.
> > 
> Rename is in progress: compcache->ramzswap :)
> 
> > Also, the kernel already has a widespread and well-established "backing
> > device" concept, in include/linux/backing-dev.h.  This new feature's
> > poaching of that identifier is a bit confusing.  It would be nice to do a
> > wholesale rename if possible.  secondary_dev?  nv_dev?
> > 
> 
> backing_swap?

Well that gets us back to my other question.  It's a block device driver,
yes?  It is in fact not tied to swap in any way, apart from swap being the
expected application?
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