Subject: Re: file creation decreases memory !
To: None <nmahajan@hss.hns.com>
From: Jason Thorpe <thorpej@wasabisystems.com>
List: tech-embed
Date: 03/02/2004 13:08:09
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On Mar 1, 2004, at 10:10 PM, nmahajan@hss.hns.com wrote:

> This goes on even if we issue sync command (wasnt it supposed to write 
> back
> these dirty pages back to disk ?)
> io_flush kernel thread has also been seen running but doesnt changes 
> these
> top output. ..
> the file in question being  say 38 MB .. and command is " cp file1 
> file 2"
>
> Can some body explain why it is happening ..

Even of the file pages are clean, they remain as cached file pages.  
This is normal behavior.  If something else needs to use that memory, 
the file page will be reclaimed for another use.

You can tune the VM system's thresholds for various types of memory 
pages.  man sysctl(8) for more information.

         -- Jason R. Thorpe <thorpej@wasabisystems.com>


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