Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 18 Dec 2008 15:13:12 -0500
From:      FreeBSD <freebsd@optiksecurite.com>
To:        freebsd-questions@freebsd.org
Subject:   Re: Simple swap question
Message-ID:  <494AAED8.2020809@optiksecurite.com>
In-Reply-To: <20081218171135.GF5150@torus.slightlystrange.org>
References:  <494A693A.5050204@optiksecurite.com> <200812181028.18306.kirk@strauser.com> <20081218163632.GE5150@torus.slightlystrange.org> <494A820E.2030907@optiksecurite.com> <20081218171135.GF5150@torus.slightlystrange.org>

next in thread | previous in thread | raw e-mail | index | archive | help
Daniel Bye a écrit :
> On Thu, Dec 18, 2008 at 12:02:06PM -0500, FreeBSD wrote:
>> Daniel Bye a ?crit :
>>> On Thu, Dec 18, 2008 at 10:28:18AM -0600, Kirk Strauser wrote:
>>>> On Thursday 18 December 2008 09:16:10 FreeBSD wrote:
>>>>> Hi everyone,
>>>>>
>>>>> I have a FreeBSD 7.0-Release server that started to swap after an error
>>>>> in a shell script (process spawning competition ;-) ). I killed the
>>>>> shell and the RAM is now OK. The problem is that the swap is still used.
>>>>> How can I "reset" the swap?
>>>> You don't.  The system will handle it for you, I promise.  :-)
>>> And very well, too.
>>>
>>> You can prompt it to move pages back into RAM if you start using a swapped-
>>> out process again - say, for example, a quiescent word processor had been
>>> swapped out, you could get it back by raising it and starting to type.
>>>
>>> But as Kirk said, there really is no need. It's one of the kernel's many
>>> jobs, and I'm inclined to leave it get on with it!
>>>
>>> Dan
>>>
>> Thanks for your answer. I'm asking here because it's been several days 
>> and there is still used swap for data that should never be used anymore. 
>> If the kernel wants to keep it, why not move it to RAM now that there is 
>> some free?
> 
> Because it has swapped out an entire process, which hasn't subsequently
> been woken up again. It's you that says the data are never going to be
> needed again - the kernel doesn't know that, so keeps the pages there in
> swap until you either reawaken the process, or kill it, at which point
> the swap space they occupied will be freed up.
> 
> You can see which processes are swapped out in top - the process name is
> in parentheses. If it is irking you sufficiently, you can kill the
> processes and reclaim your swap ;-)
> 
> Dan
> 

I can't see any process within parentheses in top... I also looked at 
the -f option of ps but the process that caused the swapping are not listed.

Thanks for helping me clarify this.

Martin



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?494AAED8.2020809>