From: Minchan Kim <minchan.kim@gmail.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>, Con Kolivas <kernel@kolivas.org>,
linux-mm@kvack.org
Subject: Re: [patch] mm: adjust kswapd nice level for high priority page allocators
Date: Wed, 3 Mar 2010 15:25:00 +0900 [thread overview]
Message-ID: <28c262361003022225k420a5e23y2eeee2c4dfdbccc3@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1003021610530.14687@chino.kir.corp.google.com>
On Wed, Mar 3, 2010 at 9:14 AM, David Rientjes <rientjes@google.com> wrote:
> On Tue, 2 Mar 2010, Minchan Kim wrote:
>
>> > Why do you reset nice value which set by set_kswapd_nice?
>>
>> My point is that you reset nice value(which is boosted at wakeup_kswapd) to 0
>> before calling balance_pgdat. It means kswapd could be rescheduled by nice 0
>> before really reclaim happens by balance_pgdat.
>
> wakeup_kswapd() wakes up kswapd at the finish_wait() point so that it has
> the nice value set by set_kswapd_nice() when it calls balance_pgdat(),
> loops, and then sets it back to the default nice level of 0.
I can't understand your point.
Now kswapd is working following as.
for (; ;) {
prepare_to_wait();
if ( ... ) {
...
...
schedule() < --- wakeup point
...
set_user_nice(tsk, 0); <-- You reset nice value to zero.
order = pgdata->kswapd_max_order;
}
finish_wait();
balance_pgdat(); << before entering balance_pgdat, the nice vaule
will be invalidated.
}
As above code, wakeup_kswapd() wakes up kswapd at not finish_wait but
next line of schedule(). So I think nice vaule promoted by
wakeup_kswapd would be invalidated.
--
Kind regards,
Minchan Kim
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prev parent reply other threads:[~2010-03-03 6:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-01 10:14 [patch] mm: adjust kswapd nice level for high priority page allocators David Rientjes
2010-03-01 13:52 ` Mel Gorman
2010-03-01 17:56 ` David Rientjes
2010-03-01 18:04 ` Mel Gorman
2010-03-08 23:23 ` David Rientjes
2010-03-02 23:48 ` Andrew Morton
2010-03-01 16:02 ` Minchan Kim
2010-03-02 4:29 ` Minchan Kim
2010-03-03 0:14 ` David Rientjes
2010-03-03 6:25 ` Minchan Kim [this message]
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