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Olaf Hering
28f25b0d33
Signed-off-by: Olaf Hering <olaf@aepfle.de> Committed-by: Keir Fraser <keir@xen.org>
46 lines
1.5 KiB
Plaintext
46 lines
1.5 KiB
Plaintext
Warning:
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The xenpaging code is new and not fully debugged.
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Usage of xenpaging can crash Xen or cause severe data corruption in the
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guest memory and its filesystems!
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Description:
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xenpaging writes memory pages of a given guest to a file and moves the
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pages back to the pool of available memory. Once the guests wants to
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access the paged-out memory, the page is read from disk and placed into
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memory. This allows the sum of all running guests to use more memory
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than physically available on the host.
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Requirements:
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xenpaging relies on Intel EPT or AMD RVI, other hardware is not
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supported. Only HVM guests are supported. The dom0 kernel needs
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paging-aware backend drivers to handle paged granttable entries.
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Currently only dom0 kernels based on classic Xen Linux support this
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functionality.
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Usage:
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Up to now xenpaging is not integrated into libxl/xend, so it has to be
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started manually for each guest.
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Once the guest is running, run xenpaging with the guest_id and the path
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to the pagefile:
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/usr/lib/xen/bin/xenpaging -f /path/to/page_file -d dom_id &
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Once xenpaging runs it needs a memory target, which is the memory
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footprint of the guest. This value (in KiB) must be written manually to
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xenstore. The following example sets the target to 512MB:
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xenstore-write /local/domain/<dom_id>/memory/target-tot_pages $((1024*512))
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Now xenpaging tries to page-out as many pages to keep the overall memory
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footprint of the guest at 512MB.
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Todo:
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- integrate xenpaging into libxl
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# vim: tw=72
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