Re: [PATCH v2 1/3] deactivate invalidated pages

From: KOSAKI Motohiro
Date: Sun Nov 28 2010 - 21:14:03 EST


> > I don't like this change because fadvise(DONT_NEED) is rarely used
> > function and this PG_reclaim trick doesn't improve so much. In the
> > other hand, It increase VM state mess.
> >
>
> Can we please stop appealing to this argument? The reason that
> fadvise(DONT_NEED) is currently rarely employed is that the interface as
> implemented now is extremely kludgey to use.
>
> Are you proposing that this particular implementation is not worth the
> mess (as opposed to putting the pages at the head of the inactive list
> as done earlier) or would you rather that we simply leave DONT_NEED in
> its current state? Even if today's gains aren't as great as we would
> like them to be, we should still make an effort to make fadvise()
> usable, if for no other reason than to encourage use in user-space so
> that applications can benefit when we finally do figure out how to
> properly account for the user's hints.

Hi

I'm not againt DONT_NEED feature. I only said PG_reclaim trick is not
so effective. Every feature has their own pros/cons. I think the cons
is too big. Also, nobody have mesured PG_reclaim performance gain. Did you?



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/