Re: RFC: Easy-Reclaimable LRU list

[Kamezawa Hiroyuki]

(2012/06/22 15:57), Minchan Kim wrote:
> Hi John,
>
> On 06/22/2012 04:21 AM, John Stultz wrote:
>
> > On 06/18/2012 10:49 PM, Minchan Kim wrote:
> > > Hi everybody!
> > >
> > > Recently, there are some efforts to handle system memory pressure.
> > >
> > > 1) low memory notification - [1]
> > > 2) fallocate(VOLATILE) - [2]
> > > 3) fadvise(NOREUSE) - [3]
> > >
> > > For them, I would like to add new LRU list, aka "Ereclaimable" which
> > > is opposite of "unevictable".
> > > Reclaimable LRU list includes _easy_ reclaimable pages.
> > > For example, easy reclaimable pages are following as.
> > >
> > > 1. invalidated but remained LRU list.
> > > 2. pageout pages for reclaim(PG_reclaim pages)
> > > 3. fadvise(NOREUSE)
> > > 4. fallocate(VOLATILE)
> > >
> > > Their pages shouldn't stir normal LRU list and compaction might not
> > > migrate them, even.
> > > Reclaimer can reclaim Ereclaimable pages before normal lru list and
> > > will avoid unnecessary
> > > swapout in anon pages in easy-reclaimable LRU list.
> >
> > I was hoping there would be further comment on this by more core VM
> > devs, but so far things have been quiet (is everyone on vacation?).
>
>
> At least, there are no dissent comment until now.
> Let be a positive. :)

I think this is interesting approach. Major concern is how to guarantee EReclaimable
pages are really EReclaimable...Do you have any idea ? madviced pages are really
EReclaimable ?

A (very) small concern is will you use one more page-flags for this ? ;)

Thanks,
-Kame





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