Am 06.06.2015 um 05:06 schrieb Dennis Jacobfeuerborn:
That's true but it also means that if you lock that page so it cannot be
swapped out then this page is not available for the page cache so you
incur the i/o hit either way and it's probably going to be worse because
the system has no longer an option to optimize the memory management.
I wouldn't worry about it until there's actually permanent swap activity
going on and then you have to decide if you want to add more ram to the
system or maybe find a way to tell e.g. Bacula to use direct i/o and not
pollute the page cache.
For application that do not allow to specify this a wrapper could be
used such as this one:
http://arighi.blogspot.de/2007/04/how-to-bypass-buffer-cache-in-linux.html
Actually I found better links:
https://code.google.com/p/pagecache-mangagement/
http://lwn.net/Articles/224653/
"It is to address the "waah, backups fill my memory with pagecache" and
the "waah, updatedb swapped everything out" and the "waah, copying a DVD
gobbled all my memory" problems."
Dennis, thanks for the links. I hope to get around using these tools.
But it's good to have them in my "arsenal" ;)
Cheers, Shorty
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