Re: [PATCH -mm] vmscan: protect a fraction of file backed mapped pages from reclaim

KOSAKI Motohiro
2009-05-14T23:28:19Z

> On Wed, 13 May 2009, KOSAKI Motohiro wrote:
>
> > > All these expiration modifications do not take into account that a desktop
> > > may sit idle for hours while some other things run in the background (like
> > > backups at night or updatedb and other maintenance things). This still
> > > means that the desktop will be usuable in the morning.
> >
> > Have you seen this phenomenom?
> > I always use linux desktop for development. but I haven't seen it.
> > perhaps I have no luck. I really want to know reproduce way.
> >
> > Please let me know reproduce way.
>
> Run a backup (or rsync) over a few hundred GB.

-ENOTREPRODUCED

umm.
May I ask detail operation?

> > > The percentage of file backed pages protected is set via
> > > /proc/sys/vm/file_mapped_ratio. This defaults to 20%.
> >
> > Why do you think typical mapped ratio is less than 20% on desktop machine?
>
> Observation of the typical mapped size of Firefox under KDE.

My point is, desktop people have very various mapped ratio.
Do you oppose this?

> > key point is access-once vs access-many.
>
> Nothing against it if it works.
>