Re: [virtio-dev] [PATCH] content: document balloon memory statistics

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Wed, Feb 21, 2018 at 12:11:35AM +0100, Tomáš Golembiovský wrote:
> On Tue, 20 Feb 2018 17:15:44 +0000
> Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> > On Mon, Feb 19, 2018 at 02:10:29PM +0100, Tomáš Golembiovský wrote:
> > > +\item[VIRTIO_BALLOON_S_CACHES (7)] The amount of memory currently used for
> > > +  caching files and other data from disk (in bytes).
> > >  \end{description}  
> > 
> > This one is somewhat vague.  I'm not sure if it means guest page cache
> > specifically or something more general.
> > 
> > On the other hand, the numbers tend to be OS specific...
> 
> We should come up with a definition that is as definite as possible
> while leaving room for all systems to substitute a value that is
> natively available. So if anyone has a better formulation then please
> advise. The original intent was not to create a Linux specific field.
> 
> On Linux the value corresponds to Buffers + Cached + SwapCached memory
> stats. Correct me if I'm wrong but that should be all clean pages that
> have a counterpart on disk and can be quickly reclaimed and used for
> something else (without additional IO).

Thanks for clarifying.  Based on what you posted, how about:

"The amount of memory, in bytes, that can be quickly reclaimed without
additional I/O.  Typically these pages are used for caching files from
disk."

?

> On Windows this roughly corresponds to the standby list. Or maybe
> standby list plus something else. I suppose there may be some
> alternative on BSD too.
> 
>     Tomas
> 
> 
> -- 
> Tomáš Golembiovský <tgolembi@redhat.com>

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