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>
36 lines
983 B
C
36 lines
983 B
C
/******************************************************************************
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* Xen balloon functionality
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*/
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#define RETRY_UNLIMITED 0
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struct balloon_stats {
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/* We aim for 'current allocation' == 'target allocation'. */
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unsigned long current_pages;
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unsigned long target_pages;
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/* Number of pages in high- and low-memory balloons. */
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unsigned long balloon_low;
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unsigned long balloon_high;
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unsigned long schedule_delay;
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unsigned long max_schedule_delay;
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unsigned long retry_count;
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unsigned long max_retry_count;
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};
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extern struct balloon_stats balloon_stats;
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void balloon_set_new_target(unsigned long target);
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int alloc_xenballooned_pages(int nr_pages, struct page** pages);
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void free_xenballooned_pages(int nr_pages, struct page** pages);
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struct sys_device;
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#ifdef CONFIG_XEN_SELFBALLOONING
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extern int register_xen_selfballooning(struct sys_device *sysdev);
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#else
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static inline int register_xen_selfballooning(struct sys_device *sysdev)
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{
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return -ENOSYS;
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}
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#endif
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