linux/include/xen/balloon.h

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/******************************************************************************
* Xen balloon functionality
*/
#define RETRY_UNLIMITED 0
struct balloon_stats {
/* We aim for 'current allocation' == 'target allocation'. */
unsigned long current_pages;
unsigned long target_pages;
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
unsigned long schedule_delay;
unsigned long max_schedule_delay;
unsigned long retry_count;
unsigned long max_retry_count;
#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
unsigned long hotplug_pages;
unsigned long balloon_hotplug;
#endif
};
extern struct balloon_stats balloon_stats;
void balloon_set_new_target(unsigned long target);
int alloc_xenballooned_pages(int nr_pages, struct page **pages,
bool highmem);
void free_xenballooned_pages(int nr_pages, struct page **pages);
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>
2011-07-08 18:26:21 +00:00
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