Re: Inactive memory keep growing and how to release it?

[Simon Jeons]

On 03/14/2013 06:14 PM, Michal Hocko wrote:
> On Mon 04-03-13 17:52:22, Lenky Gao wrote:
> > Hi,
> >
> > When i just run a test on Centos 6.2 as follows:
> >
> > #!/bin/bash
> >
> > while true
> > do
> >
> > 	file="/tmp/filetest"
> >
> > 	echo $file
> >
> > 	dd if=/dev/zero of=${file} bs=512 count=204800 &> /dev/null
> >
> > 	sleep 5
> > done
> >
> > the inactive memory keep growing:
> >
> > #cat /proc/meminfo | grep Inactive\(fi
> > Inactive(file):   420144 kB
> > ...
> > #cat /proc/meminfo | grep Inactive\(fi
> > Inactive(file):   911912 kB
> > ...
> > #cat /proc/meminfo | grep Inactive\(fi
> > Inactive(file):  1547484 kB
> > ...
> >
> > and i cannot reclaim it:
> How did you try to reclaim the memory? How much memory is still free?
> Are you above watermaks (/proc/zoneinfo will tell you more)
>
> > # cat /proc/meminfo | grep Inactive\(fi
> > Inactive(file):  1557684 kB
> > # echo 3 > /proc/sys/vm/drop_caches
> > # cat /proc/meminfo | grep Inactive\(fi
> > Inactive(file):  1520832 kB
> >
> > I have tested on other version kernel, such as 2.6.30 and .6.11, the
> > problom also exists.
> >
> > When in the final situation, i cannot kmalloc a larger contiguous
> > memory, especially in interrupt context.
> This could be related to the memory fragmentation and your kernel seem
> to be too large to have memory compaction which helps a lot in that
> area.
>
> > Can you give some tips to avoid this?
> One way would be to increase /proc/sys/vm/min_free_kbytes which will
> enlarge watermaks so the reclaim starts sooner.
>   
> > PS:
> > # uname -a
> > Linux localhost.localdomain 2.6.32-220.el6.x86_64 #1 SMP Tue Dec 6
> > 19:48:22 GMT 2011 x86_64 x86_64 x86_64 GNU/Linux
> This is really an old kernel and also a distribution one which might
> contain a lot of patches on top of the core kernel. I would suggest to
> contact Redhat or try to reproduce the issue with the vanilla and

What's the meaning of vanilla?

> up-to-date kernel and report here.

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