1Warning:
2
3The xenpaging code is new and not fully debugged.
4Usage of xenpaging can crash Xen or cause severe data corruption in the
5guest memory and its filesystems!
6
7Description:
8
9xenpaging writes memory pages of a given guest to a file and moves the
10pages back to the pool of available memory.  Once the guests wants to
11access the paged-out memory, the page is read from disk and placed into
12memory.  This allows the sum of all running guests to use more memory
13than physically available on the host.
14
15Requirements:
16
17xenpaging relies on Intel EPT or AMD RVI, other hardware is not
18supported. Only HVM guests are supported.  The dom0 kernel needs
19paging-aware backend drivers to handle paged granttable entries.
20Currently only dom0 kernels based on classic Xen Linux support this
21functionality.
22
23Usage:
24
25Up to now xenpaging is not integrated into libxl/xend, so it has to be
26started manually for each guest.
27
28Once the guest is running, run xenpaging with the guest_id and the path
29to the pagefile:
30
31 /usr/lib/xen/bin/xenpaging -f /path/to/page_file -d dom_id &
32
33Once xenpaging runs it needs a memory target, which is the memory
34footprint of the guest. This value (in KiB) must be written manually to
35xenstore. The following example sets the target to 512MB:
36
37 xenstore-write /local/domain/<dom_id>/memory/target-tot_pages $((1024*512))
38
39Now xenpaging tries to page-out as many pages to keep the overall memory
40footprint of the guest at 512MB.
41
42Todo:
43- integrate xenpaging into libxl
44
45# vim: tw=72
46