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a50777c791
This patch introduces two in-kernel drivers for Xen transcendent memory
("tmem") functionality that complement cleancache and frontswap. Both
use control theory to dynamically adjust and optimize memory utilization.
Selfballooning controls the in-kernel Xen balloon driver, targeting a goal
value (vm_committed_as), thus pushing less frequently used clean
page cache pages (through the cleancache code) into Xen tmem where
Xen can balance needs across all VMs residing on the physical machine.
Frontswap-selfshrinking controls the number of pages in frontswap,
driving it towards zero (effectively doing a partial swapoff) when
in-kernel memory pressure subsides, freeing up RAM for other VMs.
More detail is provided in the header comment of xen-selfballooning.c.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v8: konrad.wilk@oracle.com: set default enablement depending on frontswap]
[v7: konrad.wilk@oracle.com: fix capitalization and punctuation in comments]
[v6: fix frontswap-selfshrinking initialization]
[v6: konrad.wilk@oracle.com: fix init pr_infos; add comments about swap]
[v5: konrad.wilk@oracle.com: add NULL to attr list; move inits up to decls]
[v4: dkiper@net-space.pl: use strict_strtoul plus a few syntactic nits]
[v3: konrad.wilk@oracle.com: fix potential divides-by-zero]
[v3: konrad.wilk@oracle.com: add many more comments, fix nits]
[v2: rebased to linux-3.0-rc1]
[v2: Ian.Campbell@citrix.com: reorganize as new file (xen-selfballoon.c)]
[v2: dkiper@net-space.pl: proper access to vm_committed_as]
[v2: dkiper@net-space.pl: accounting fixes]
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: <xen-devel@lists.xensource.com>
126 lines
4.0 KiB
Plaintext
126 lines
4.0 KiB
Plaintext
menu "Xen driver support"
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depends on XEN
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config XEN_BALLOON
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bool "Xen memory balloon driver"
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default y
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help
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The balloon driver allows the Xen domain to request more memory from
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the system to expand the domain's memory allocation, or alternatively
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return unneeded memory to the system.
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config XEN_SELFBALLOONING
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bool "Dynamically self-balloon kernel memory to target"
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depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP
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default n
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help
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Self-ballooning dynamically balloons available kernel memory driven
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by the current usage of anonymous memory ("committed AS") and
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controlled by various sysfs-settable parameters. Configuring
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FRONTSWAP is highly recommended; if it is not configured, self-
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ballooning is disabled by default but can be enabled with the
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'selfballooning' kernel boot parameter. If FRONTSWAP is configured,
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frontswap-selfshrinking is enabled by default but can be disabled
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with the 'noselfshrink' kernel boot parameter; and self-ballooning
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is enabled by default but can be disabled with the 'noselfballooning'
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kernel boot parameter. Note that systems without a sufficiently
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large swap device should not enable self-ballooning.
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config XEN_SCRUB_PAGES
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bool "Scrub pages before returning them to system"
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depends on XEN_BALLOON
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default y
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help
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Scrub pages before returning them to the system for reuse by
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other domains. This makes sure that any confidential data
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is not accidentally visible to other domains. Is it more
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secure, but slightly less efficient.
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If in doubt, say yes.
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config XEN_DEV_EVTCHN
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tristate "Xen /dev/xen/evtchn device"
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default y
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help
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The evtchn driver allows a userspace process to triger event
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channels and to receive notification of an event channel
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firing.
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If in doubt, say yes.
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config XEN_BACKEND
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bool "Backend driver support"
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depends on XEN_DOM0
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default y
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help
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Support for backend device drivers that provide I/O services
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to other virtual machines.
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config XENFS
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tristate "Xen filesystem"
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default y
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help
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The xen filesystem provides a way for domains to share
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information with each other and with the hypervisor.
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For example, by reading and writing the "xenbus" file, guests
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may pass arbitrary information to the initial domain.
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If in doubt, say yes.
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config XEN_COMPAT_XENFS
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bool "Create compatibility mount point /proc/xen"
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depends on XENFS
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default y
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help
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The old xenstore userspace tools expect to find "xenbus"
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under /proc/xen, but "xenbus" is now found at the root of the
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xenfs filesystem. Selecting this causes the kernel to create
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the compatibility mount point /proc/xen if it is running on
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a xen platform.
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If in doubt, say yes.
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config XEN_SYS_HYPERVISOR
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bool "Create xen entries under /sys/hypervisor"
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depends on SYSFS
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select SYS_HYPERVISOR
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default y
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help
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Create entries under /sys/hypervisor describing the Xen
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hypervisor environment. When running native or in another
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virtual environment, /sys/hypervisor will still be present,
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but will have no xen contents.
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config XEN_XENBUS_FRONTEND
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tristate
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config XEN_GNTDEV
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tristate "userspace grant access device driver"
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depends on XEN
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default m
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select MMU_NOTIFIER
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help
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Allows userspace processes to use grants.
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config XEN_GRANT_DEV_ALLOC
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tristate "User-space grant reference allocator driver"
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depends on XEN
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default m
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help
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Allows userspace processes to create pages with access granted
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to other domains. This can be used to implement frontend drivers
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or as part of an inter-domain shared memory channel.
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config XEN_PLATFORM_PCI
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tristate "xen platform pci device driver"
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depends on XEN_PVHVM && PCI
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default m
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help
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Driver for the Xen PCI Platform device: it is responsible for
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initializing xenbus and grant_table when running in a Xen HVM
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domain. As a consequence this driver is required to run any Xen PV
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frontend on Xen HVM.
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config SWIOTLB_XEN
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def_bool y
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depends on PCI
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select SWIOTLB
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endmenu
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