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From: Pavel Machek <pavel@ucw.cz>
To: Con Kolivas <kernel@kolivas.org>
Cc: "Martin J. Bligh" <mbligh@aracnet.com>,
	linux kernel mailing list <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] Autoregulate vm swappiness cleanup
Date: Tue, 28 Oct 2003 12:04:45 +0100	[thread overview]
Message-ID: <20031028110443.GA1792@elf.ucw.cz> (raw)
In-Reply-To: <200310251658.23070.kernel@kolivas.org>

Hi!

> > > It seems that you don't need si_swapinfo here, do you? i.freeram,
> > > i.bufferram, and i.totalram all come from meminfo, as far as I can
> > > see? Maybe I'm missing a bit ...
> >
> > Well I did do it a while ago and it seems I got carried away adding and
> > subtracting info indeed. :-) Here's a simpler patch that does the same
> > thing.
> 
> The off-list enthusiasm has been rather strong so here is a patch done the 
> right way (tm). There is no need for the check of totalram being zero (the 
> original version of this patch modified the swappiness every tick which was 
> wasteful and had a divide by zero on init). Adjusting vm_swappiness only when 
> there is pressure to swap means totalram shouldn't be ever be zero. The 
> sysctl is made read only since writing to it would be ignored now.

I believe swappiness == 100 was "I want max throughput, I don't care
about latency going through roof", while swappiness == 0 was "I don't
want you to swap too much, behave reasonably".

As you don't know if user cares about latency or not, I don't see how
you can autotune this.

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]

  parent reply	other threads:[~2003-10-28 11:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-10-23 13:37 [PATCH] Autoregulate vm swappiness 2.6.0-test8 Con Kolivas
2003-10-23 14:42 ` Martin J. Bligh
2003-10-23 15:03   ` Con Kolivas
2003-10-25  6:58     ` [PATCH] Autoregulate vm swappiness cleanup Con Kolivas
2003-10-26 11:22       ` Nick Piggin
2003-10-26 10:36         ` Con Kolivas
2003-10-26 11:42           ` Nick Piggin
2003-10-28 11:04       ` Pavel Machek [this message]
2003-10-28 12:40         ` Con Kolivas
  -- strict thread matches above, loose matches on Subject: below --
2003-10-28 13:34 Boszormenyi Zoltan
2003-10-28 14:39 ` Richard B. Johnson
2003-10-28 15:39   ` Valdis.Kletnieks
2003-10-28 15:54     ` Richard B. Johnson
2003-10-28 16:37       ` Valdis.Kletnieks
2003-10-28 16:51         ` Måns Rullgård
2003-10-28 17:33           ` Valdis.Kletnieks

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