Re: [RFC 4/8] Make clear description of putback_lru_page

From: KOSAKI Motohiro
Date: Sun May 01 2011 - 09:13:45 EST


> On Thu, Apr 28, 2011 at 08:20:32AM +0900, Minchan Kim wrote:
> > On Wed, Apr 27, 2011 at 5:11 PM, KAMEZAWA Hiroyuki
> > <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > > On Wed, 27 Apr 2011 01:25:21 +0900
> > > Minchan Kim <minchan.kim@xxxxxxxxx> wrote:
> > >
> > >> Commonly, putback_lru_page is used with isolated_lru_page.
> > >> The isolated_lru_page picks the page in middle of LRU and
> > >> putback_lru_page insert the lru in head of LRU.
> > >> It means it could make LRU churning so we have to be very careful.
> > >> Let's clear description of putback_lru_page.
> > >>
> > >> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> > >> Cc: Mel Gorman <mgorman@xxxxxxx>
> > >> Cc: Rik van Riel <riel@xxxxxxxxxx>
> > >> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> > >> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> > >
> > > seems good...
> > > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > >
> > > But is there consensus which side of LRU is tail? head?
> >
> > I don't know. I used to think it's head.
> > If other guys raise a concern as well, let's talk about it. :)
> > Thanks
>
> I suppose we add new pages to the head of the LRU and reclaim old
> pages from the tail.
>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

So, It would be better if isolate_lru_page() also have "LRU tail blah blah blah"
comments.

anyway,
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>



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