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2015-10-23xen/balloon: use hotplugged pages for foreign mappings etc.David Vrabel1-0/+1
alloc_xenballooned_pages() is used to get ballooned pages to back foreign mappings etc. Instead of having to balloon out real pages, use (if supported) hotplugged memory. This makes more memory available to the guest and reduces fragmentation in the p2m. This is only enabled if the xen.balloon.hotplug_unpopulated sysctl is set to 1. This sysctl defaults to 0 in case the udev rules to automatically online hotplugged memory do not exist. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- v3: - Add xen.balloon.hotplug_unpopulated sysctl to enable use of hotplug for unpopulated pages.
2015-10-23xen/balloon: make alloc_xenballoon_pages() always allocate low pagesDavid Vrabel1-2/+1
All users of alloc_xenballoon_pages() wanted low memory pages, so remove the option for high memory. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2015-10-23xen/balloon: rationalize memory hotplug statsDavid Vrabel1-4/+1
The stats used for memory hotplug make no sense and are fiddled with in odd ways. Remove them and introduce total_pages to track the total number of pages (both populated and unpopulated) including those within hotplugged regions (note that this includes not yet onlined pages). This will be used in a subsequent commit (xen/balloon: only hotplug additional memory if required) when deciding whether additional memory needs to be hotplugged. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2015-10-23xen/balloon: remove scratch page left oversDavid Vrabel1-3/+0
Commit 0bb599fd30108883b00c7d4a226eeb49111e6932 (xen: remove scratch frames for ballooned pages and m2p override) removed the use of the scratch page for ballooned out pages. Remove some left over function definitions. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2013-08-09xen/balloon: set a mapping for ballooned out pagesStefano Stabellini1-0/+3
Currently ballooned out pages are mapped to 0 and have INVALID_P2M_ENTRY in the p2m. These ballooned out pages are used to map foreign grants by gntdev and blkback (see alloc_xenballooned_pages). Allocate a page per cpu and map all the ballooned out pages to the corresponding mfn. Set the p2m accordingly. This way reading from a ballooned out page won't cause a kernel crash (see http://lists.xen.org/archives/html/xen-devel/2012-12/msg01154.html). Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> CC: alex@alex.org.uk CC: dcrisan@flexiant.com Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-14xen-balloon: convert sysdev_class to a regular subsystemKay Sievers1-3/+3
After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-09-29xen: add an "highmem" parameter to alloc_xenballooned_pagesStefano Stabellini1-2/+3
Add an highmem parameter to alloc_xenballooned_pages, to allow callers to request lowmem or highmem pages. Fix the code style of free_xenballooned_pages' prototype. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-07-25xen/balloon: memory hotplug support for Xen balloon driverDaniel Kiper1-0/+4
Memory hotplug support for Xen balloon driver. It should be mentioned that hotplugged memory is not onlined automatically. It should be onlined by user through standard sysfs interface. Memory could be hotplugged in following steps: 1) dom0: xl mem-max <domU> <maxmem> where <maxmem> is >= requested memory size, 2) dom0: xl mem-set <domU> <memory> where <memory> is requested memory size; alternatively memory could be added by writing proper value to /sys/devices/system/xen_memory/xen_memory0/target or /sys/devices/system/xen_memory/xen_memory0/target_kb on dumU, 3) domU: for i in /sys/devices/system/memory/memory*/state; do \ [ "`cat "$i"`" = offline ] && echo online > "$i"; done Memory could be onlined automatically on domU by adding following line to udev rules: SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'" In that case step 3 should be omitted. Signed-off-by: Daniel Kiper <dkiper@net-space.pl> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-08xen: tmem: self-ballooning and frontswap-selfshrinkingDan Magenheimer1-0/+10
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>
2011-03-16xen-balloon: Add interface to retrieve ballooned pagesKonrad Rzeszutek Wilk1-0/+3
Pages that have been ballooned are useful for other Xen drivers doing grant table actions, because these pages have valid struct page/PFNs but have no valid MFN so are available for remapping. Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> [v2: Deal with rebasing on top of modified balloon code] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-03-16xen-balloon: Move core balloon functionality out of moduleDaniel De Graaf1-0/+22
The basic functionality of ballooning pages is useful for Xen drivers in general. Rather than require a dependency on the balloon module, split the functionality that is reused into the core. The balloon module is still required to follow ballooning requests from xenstore or to view balloon statistics in sysfs. Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2008-10-03xen: remove unused balloon.hJeremy Fitzhardinge1-61/+0
The balloon driver doesn't have any externally callable functions at the moment, so remove the (effectively empty) header. We can add it back if we need to. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24xen: add balloon driverJeremy Fitzhardinge1-0/+61
The balloon driver allows memory to be dynamically added or removed from the domain, in order to allow host memory to be balanced between multiple domains. This patch introduces the Xen balloon driver, though it currently only allows a domain to be shrunk from its initial size (and re-grown back to that size). A later patch will add the ability to grow a domain beyond its initial size. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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