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| author | Dan Magenheimer <dan.magenheimer@oracle.com> | 2011-07-08 12:26:21 -0600 |
|---|---|---|
| committer | Dan Magenheimer <dan.magenheimer@oracle.com> | 2011-07-08 12:26:21 -0600 |
| commit | a50777c791031d7345ce95785ea6220f67339d90 (patch) | |
| tree | 8246cc346988df9cdaf3e2cea2b0e8eb20156fd7 /drivers/xen/Kconfig | |
| parent | 55922c9d1b84b89cb946c777fddccb3247e7df2c (diff) | |
| download | lwn-a50777c791031d7345ce95785ea6220f67339d90.tar.gz lwn-a50777c791031d7345ce95785ea6220f67339d90.zip | |
xen: tmem: self-ballooning and frontswap-selfshrinking
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>
Diffstat (limited to 'drivers/xen/Kconfig')
| -rw-r--r-- | drivers/xen/Kconfig | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index a59638b37c1a..fd3266696a4d 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -9,6 +9,23 @@ config XEN_BALLOON the system to expand the domain's memory allocation, or alternatively return unneeded memory to the system. +config XEN_SELFBALLOONING + bool "Dynamically self-balloon kernel memory to target" + depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP + default n + help + Self-ballooning dynamically balloons available kernel memory driven + by the current usage of anonymous memory ("committed AS") and + controlled by various sysfs-settable parameters. Configuring + FRONTSWAP is highly recommended; if it is not configured, self- + ballooning is disabled by default but can be enabled with the + 'selfballooning' kernel boot parameter. If FRONTSWAP is configured, + frontswap-selfshrinking is enabled by default but can be disabled + with the 'noselfshrink' kernel boot parameter; and self-ballooning + is enabled by default but can be disabled with the 'noselfballooning' + kernel boot parameter. Note that systems without a sufficiently + large swap device should not enable self-ballooning. + config XEN_SCRUB_PAGES bool "Scrub pages before returning them to system" depends on XEN_BALLOON |