5.6. KSM

Kernel shared memory (KSM) enables the kernel to examine two or more already running programs and compare their memory. If any pages are identical, KSM merges multiple identical memory pages to a single page. This page is then marked as copy on write (COW), and can be shared among system processes. The ksm service starts and stops the KSM thread, and the ksmtuned service controls and tunes the ksm service. For information on KSM and its tuning, see the KSM chapter of the Red Hat Enterprise Linux 6 Virtualization Administration Guide.