2005-10-05 12:57:24

by Con Kolivas

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Subject: [PATCH] vm - swap prefetch v14

Here is the latest version of the swap prefetching patch. This code is now
considered quite stable.

Changes:
-The longstanding bug which created swapcache pages that were pinned to ram
and could only be removed by doing a swapoff was tracked down and fixed.
-Rate of free ram allocation is watched as an indirect and cheap method of
determining if any significantly sized file reads are in progress.
-I/O priority support was added.
-The tunable to determine the amount of data retrieved per prefetch was added
/proc/sys/vm/swap_prefetch
is used to decide how many groups of 128kb to prefetch per 1 second interval
and is set to 2 by default. It can be disabled by setting it to 0

Incrementals and latest version available here:
http://ck.kolivas.org/patches/swap-prefetch/
(this is the same as the version in 2.6.13-ck7)

Cheers,
Con


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2005-10-05 18:02:10

by Ingo Oeser

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Subject: Re: [PATCH] vm - swap prefetch v14

Hi Con,

your patch still contains a serious BUG :-)

On Wednesday 05 October 2005 14:57, Con Kolivas wrote:
> -The tunable to determine the amount of data retrieved per prefetch was added
> /proc/sys/vm/swap_prefetch
> is used to decide how many groups of 128kb to prefetch per 1 second interval
> and is set to 2 by default. It can be disabled by setting it to 0

swap_prefetch is not documented at Documentation/sysctl/vm.txt

This simple text would suffice I think. Maybe comment about disabling it
for laptop usage.


Regards

Ingo Oeser


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2005-10-06 13:39:36

by Con Kolivas

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Subject: Re: [PATCH] vm - swap prefetch v14

On Thu, 6 Oct 2005 04:01 am, Ingo Oeser wrote:
> Hi Con,
>
> your patch still contains a serious BUG :-)
>
> On Wednesday 05 October 2005 14:57, Con Kolivas wrote:
> > -The tunable to determine the amount of data retrieved per prefetch was
> > added /proc/sys/vm/swap_prefetch
> > is used to decide how many groups of 128kb to prefetch per 1 second
> > interval and is set to 2 by default. It can be disabled by setting it to
> > 0
>
> swap_prefetch is not documented at Documentation/sysctl/vm.txt
>
> This simple text would suffice I think. Maybe comment about disabling it
> for laptop usage.

Thanks for the suggestion. I'll add the Documentation entry and you reminded
me to do something specific with laptop mode which I have for v15 I'm about
to announce.

Cheers,
Con