Re: [RFC] Remove unswappable anonymous pages off the LRU

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Thu, 15 Feb 2007 17:13:55 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Thu, 15 Feb 2007 13:05:47 -0800 (PST)
> Christoph Lameter <clameter@sgi.com> wrote:
> 
> > If we do not have any swap or we have run out of swap then anonymous pages
> > can no longer be removed from memory. In that case we simply treat them
> > like mlocked pages. For a kernel compiled CONFIG_SWAP off this means
> > that all anonymous pages are marked mlocked when they are allocated.
> 
> It's nice and simple, but I think I'd prefer to wait for the existing mlock
> changes to crash a bit less before we do this.
> 
> Is it true that PageMlocked() pages are never on the LRU?  If so, perhaps
> we could overload the lru.next/prev on these pages to flag an mlocked page.
> 
> #define PageMlocked(page)	(page->lru.next == some_address_which_isnt_used_for_anwything_else)
> 

I think mlocked pages are not reclaimable but movable.
So some structure should link them to a list...


-Kame



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