Red Hat ENTERPRISE LINUX 5.1 - LINUX ORACLE Tuning Manual page 18

Chapter 5. Memory Usage and Page Cache
Alternatively, you can use sysctl(8) to change it:
# sysctl -w vm.pagecache="1 15 30"
To make the change permanent, add the following line to the file /etc/sysctl.conf. This file is
used during the boot process.
# echo "vm.pagecache=1 15 30" >> /etc/sysctl.conf
With Red Hat Enterprise Linux 4 and 5, the pagecache is dynamically adjusted. You can adjust the
minimum free pages using the following command:
# echo 1024 > /proc/sys/vm/min_free_kbytes
To make the change permanent, add the following line to the file /etc/sysctl.conf:
# echo vm.min_free_kbytes=1024 >> /etc/sysctl.conf
The pagecache pages can be reclaimed by adjusting the swappiness percentage as described in
the next section.
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