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authorDan Magenheimer <dan.magenheimer@oracle.com>2011-07-08 12:26:21 -0600
committerDan Magenheimer <dan.magenheimer@oracle.com>2011-07-08 12:26:21 -0600
commita50777c791031d7345ce95785ea6220f67339d90 (patch)
tree8246cc346988df9cdaf3e2cea2b0e8eb20156fd7 /include/xen/balloon.h
parent55922c9d1b84b89cb946c777fddccb3247e7df2c (diff)
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 'include/xen/balloon.h')
-rw-r--r--include/xen/balloon.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/xen/balloon.h b/include/xen/balloon.h
index a2b22f01a51d..4076ed72afbd 100644
--- a/include/xen/balloon.h
+++ b/include/xen/balloon.h
@@ -23,3 +23,13 @@ void balloon_set_new_target(unsigned long target);
int alloc_xenballooned_pages(int nr_pages, struct page** pages);
void free_xenballooned_pages(int nr_pages, struct page** pages);
+
+struct sys_device;
+#ifdef CONFIG_XEN_SELFBALLOONING
+extern int register_xen_selfballooning(struct sys_device *sysdev);
+#else
+static inline int register_xen_selfballooning(struct sys_device *sysdev)
+{
+ return -ENOSYS;
+}
+#endif

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