All the caller of xen_tmem_{get,put}_page have a struct page * in hand
and call pfn_to_gfn for the only benefits of these 2 functions.
Rather than passing the pfn in parameter, pass directly the page and use
directly xen_page_to_gfn.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN
is meant, I suspect this is because the first support for Xen was for
PV. This resulted in some misimplementation of helpers on ARM and
confused developers about the expected behavior.
For instance, with pfn_to_mfn, we expect to get an MFN based on the name.
Although, if we look at the implementation on x86, it's returning a GFN.
For clarity and avoid new confusion, replace any reference to mfn with
gfn in any helpers used by PV drivers. The x86 code will still keep some
reference of pfn_to_mfn which may be used by all kind of guests
No changes as been made in the hypercall field, even
though they may be invalid, in order to keep the same as the defintion
in xen repo.
Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a
name to close to the KVM function gfn_to_page.
Take also the opportunity to simplify simple construction such
as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up
will come in follow-up patches.
[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
- Add "make xenconfig" to assist in generating configs for Xen guests.
- Preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests.
- Automatically use hvc0 as the default console in ARM guests.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJVkpoqAAoJEFxbo/MsZsTRu3IH/2AMPx2i65hoSqfHtGf3sz/z
XNfcidVmOElFVXGaW83m0tBWMemT5LpOGRfiq5sIo8xt/8xD2vozEkl/3kkf3RrX
EmZDw3E8vmstBdBTjWdovVhNenRc0m0pB5daS7wUdo9cETq1ag1L3BHTB3fEBApO
74V6qAfnhnq+snqWhRD3XAk3LKI0nWuWaV+5HsmxDtnunGhuRLGVs7mwxZGg56sM
mILA0eApGPdwyVVpuDe0SwV52V8E/iuVOWTcomGEN2+cRWffG5+QpHxQA8bOtF6O
KfqldiNXOY/idM+5+oSm9hespmdWbyzsFqmTYz0LvQvxE8eEZtHHB3gIcHkE8QU=
=danz
-----END PGP SIGNATURE-----
Merge tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from David Vrabel:
"Xen features and cleanups for 4.2-rc0:
- add "make xenconfig" to assist in generating configs for Xen guests
- preparatory cleanups necessary for supporting 64 KiB pages in ARM
guests
- automatically use hvc0 as the default console in ARM guests"
* tag 'for-linus-4.2-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
block/xen-blkback: s/nr_pages/nr_segs/
block/xen-blkfront: Remove invalid comment
block/xen-blkfront: Remove unused macro MAXIMUM_OUTSTANDING_BLOCK_REQS
arm/xen: Drop duplicate define mfn_to_virt
xen/grant-table: Remove unused macro SPP
xen/xenbus: client: Fix call of virt_to_mfn in xenbus_grant_ring
xen: Include xen/page.h rather than asm/xen/page.h
kconfig: add xenconfig defconfig helper
kconfig: clarify kvmconfig is for kvm
xen/pcifront: Remove usage of struct timeval
xen/tmem: use BUILD_BUG_ON() in favor of BUG_ON()
hvc_xen: avoid uninitialized variable warning
xenbus: avoid uninitialized variable warning
xen/arm: allow console=hvc0 to be omitted for guests
arm,arm64/xen: move Xen initialization earlier
arm/xen: Correctly check if the event channel interrupt is present
Change frontswap single pointer to a singly linked list of frontswap
implementations. Update Xen tmem implementation as register no longer
returns anything.
Frontswap only keeps track of a single implementation; any
implementation that registers second (or later) will replace the
previously registered implementation, and gets a pointer to the previous
implementation that the new implementation is expected to pass all
frontswap functions to if it can't handle the function itself. However
that method doesn't really make much sense, as passing that work on to
every implementation adds unnecessary work to implementations; instead,
frontswap should simply keep a list of all registered implementations
and try each implementation for any function. Most importantly, neither
of the two currently existing frontswap implementations in the kernel
actually do anything with any previous frontswap implementation that
they replace when registering.
This allows frontswap to successfully manage multiple implementations by
keeping a list of them all.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using xen/page.h will be necessary later for using common xen page
helpers.
As xen/page.h already include asm/xen/page.h, always use the later.
Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Currently, cleancache_register_ops returns the previous value of
cleancache_ops to allow chaining. However, chaining, as it is
implemented now, is extremely dangerous due to possible pool id
collisions. Suppose, a new cleancache driver is registered after the
previous one assigned an id to a super block. If the new driver assigns
the same id to another super block, which is perfectly possible, we will
have two different filesystems using the same id. No matter if the new
driver implements chaining or not, we are likely to get data corruption
with such a configuration eventually.
This patch therefore disables the ability to override cleancache_ops
altogether as potentially dangerous. If there is already cleancache
driver registered, all further calls to cleancache_register_ops will
return EBUSY. Since no user of cleancache implements chaining, we only
need to make minor changes to the code outside the cleancache core.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As a module_init() function, this should have been this way from the
beginning.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* Fix memory leak when CPU hotplugging.
* Compile bugs with various #ifdefs
* Fix state changes in Xen PCI front not dealing well with new toolstack.
* Cleanups in code (use pr_*, fix 80 characters splits, etc)
* Long standing bug in double-reporting the steal time
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.13 (GNU/Linux)
iQEcBAABAgAGBQJR0Xc1AAoJEFjIrFwIi8fJo68H/jZaJJmytDI7exHTyq8fSGXQ
5OERw5YZeM5jZQG55YC5hmGS5oIpKEdBt+aAEpuofYUhrR/ZFqDr0j+QEiqC36bl
cl0/IAnMBGnyyO6FYY4Sut2H+S5BGYQNbwo9YAtgKtZANr2eLABxYUfMU44I/jCW
M7DAojME9OZLBW3ORYZTGf1A0T8hJINhxZIWhtLMrkckCb9AZMieKdMOHJEWq2jl
aPxx78U+2CLTdLquOLIiBEiTO3vAzx2Wt4prD+uCizWna45H9gBj7GFwBYH7p9Ry
TFyzmDc5PufThTilfDyQW1y4yiNLpFDC/67a1wpwObEBn87hstHgwHQQ5INzqwY=
=Ej7M
-----END PGP SIGNATURE-----
Merge tag 'stable/for-linus-3.11-rc0-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull Xen bugfixes from Konrad Rzeszutek Wilk:
- Fix memory leak when CPU hotplugging.
- Compile bugs with various #ifdefs
- Fix state changes in Xen PCI front not dealing well with new
toolstack.
- Cleanups in code (use pr_*, fix 80 characters splits, etc)
- Long standing bug in double-reporting the steal time
* tag 'stable/for-linus-3.11-rc0-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/time: remove blocked time accounting from xen "clockchip"
xen: Convert printks to pr_<level>
xen: ifdef CONFIG_HIBERNATE_CALLBACKS xen_*_suspend
xen/pcifront: Deal with toolstack missing 'XenbusStateClosing' state.
xen/time: Free onlined per-cpu data structure if we want to online it again.
xen/time: Check that the per_cpu data structure has data before freeing.
xen/time: Don't leak interrupt name when offlining.
xen/time: Encapsulate the struct clock_event_device in another structure.
xen/spinlock: Don't leak interrupt name when offlining.
xen/smp: Don't leak interrupt name when offlining.
xen/smp: Set the per-cpu IRQ number to a valid default.
xen/smp: Introduce a common structure to contain the IRQ name and interrupt line.
xen/smp: Coalesce the free_irq calls in one function.
xen-pciback: fix error return code in pcistub_irq_handler_switch()
Convert printks to pr_<level> (excludes printk(KERN_DEBUG...)
to be more consistent throughout the xen subsystem.
Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME
Coalesce formats and add missing word spaces
Add missing newlines
Align arguments and reflow to 80 columns
Remove DRV_NAME from formats as pr_fmt adds the same content
This does change some of the prefixes of these messages
but it also does make them more consistent.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Commit 10a7a07713 ("xen: tmem: enable Xen
tmem shim to be built/loaded as a module") allows the tmem module
to be loaded any time. For this work the frontswap API had to
be able to asynchronously to call tmem_frontswap_init before
or after the swap image had been set. That was added in git
commit 905cd0e1bf
("mm: frontswap: lazy initialization to allow tmem backends to build/run as modules").
Which means we could do this (The common case):
modprobe tmem [so calls frontswap_register_ops, no ->init]
modifies tmem_frontswap_poolid = -1
swapon /dev/xvda1 [__frontswap_init, calls -> init, tmem_frontswap_poolid is
< 0 so tmem hypercall done]
Or the failing one:
swapon /dev/xvda1 [calls __frontswap_init, sets the need_init bitmap]
modprobe tmem [calls frontswap_register_ops, -->init calls, finds out
tmem_frontswap_poolid is 0, does not make a hypercall.
Later in the module_init, sets tmem_frontswap_poolid=-1]
Which meant that in the failing case we would not call the hypercall
to initialize the pool and never be able to make any frontswap
backend calls.
Moving the frontswap_register_ops after setting the tmem_frontswap_poolid
fixes it.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
In the (not so useful) kernel configuration where CONFIG_SWAP
is undefined and CONFIG_XEN_SELFBALLOONING is defined,
xen_tmem_init would use undefined variable 'static bool frontswap'.
Added #else to have #define frontswap (0) in the case where
CONFIG_FRONTSWAP is not defined.
Signed-off-by: Frederico Cadete <frederico@cadete.eu>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
There is no point. We would just squeeze the guest to put more and
more pages in the swap disk without any purpose.
The only time it makes sense to use the selfballooning and shrinking
is when frontswap is being utilized.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If tmem is built-in or a module, the user has the option on
the command line to influence it by doing: tmem.<some option>
instead of having a variety of "nocleancache", and
"nofrontswap". The others: "noselfballooning" and "selfballooning";
and "noselfshrink" are in a different driver xen-selfballoon.c
and the patches:
xen/tmem: Remove the usage of 'noselfshrink' and use 'tmem.selfshrink' bool instead.
xen/tmem: Remove the usage of 'noselfballoon','selfballoon' and use 'tmem.selfballon' bool instead.
remove them.
Also add documentation.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The variety of disable_[cleancache|frontswap|selfshrinking] are
making this a bit complex. Just remove the "disable_" part and
change the logic around for the "nofrontswap" and "nocleancache"
parameters.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We keep on getting:
drivers/xen/tmem.c:65:13: warning: ‘disable_frontswap_selfshrinking’ defined but not used [-Wunused-variable]
if CONFIG_FRONTSWAP=y and # CONFIG_CLEANCACHE is not set
Found by 0 day test project
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
There are three options - depending on what combination of
CONFIG_FRONTSWAP, CONFIG_CLEANCACHE and CONFIG_XEN_SELFBALLOONING
is used. Lets split them out nicely out in three groups to
make it easier to clean up.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
In the past it either used to be NULL or the "older" backend. Now we
also return -Exx error codes.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow Xen tmem shim to be built/loaded as a module. Xen self-ballooning
and frontswap-selfshrinking are now also "lazily" initialized when the
Xen tmem shim is loaded as a module, unless explicitly disabled by
module parameters.
Note runtime dependency disallows loading if cleancache/frontswap lazy
initialization patches are not present.
If built-in (not built as a module), the original mechanism of enabling
via a kernel boot parameter is retained, but this should be considered
deprecated.
Note that module unload is explicitly not yet supported.
[v1: Removed the [CLEANCACHE|FRONTSWAP]_HAS_LAZY_INIT ifdef]
[v2: Squashed the xen/tmem: Remove the subsys call patch in]
[akpm@linux-foundation.org: fix build (disable_frontswap_selfshrinking undeclared)]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of using a backend_registered to determine whether a backend is
enabled. This allows us to remove the backend_register check and just
do 'if (cleancache_ops)'
[v1: Rebase on top of b97c4b430b0a (ramster->zcache move]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This simplifies the code in the frontswap - we can get rid of the
'backend_registered' test and instead check against frontswap_ops.
[v1: Rebase on top of 703ba7fe5e (ramster->zcache move]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need for those functions/variables to be visible. Make them
static and also fix the compile warnings of this sort:
drivers/xen/<some file>.c: warning: symbol '<blah>' was not declared. Should it be static?
Some of them just require including the header file that
declares the functions.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Add fast-EOI acking of interrupts (clear a bit instead of hypercall)
And bug-fixes:
* Fix CPU bring-up code missing a call to notify other subsystems.
* Fix reading /sys/hypervisor even if PVonHVM drivers are not loaded.
* In Xen ACPI processor driver: remove too verbose WARN messages, fix up
the Kconfig dependency to be a module by default, and add dependency on
CPU_FREQ.
* Disable CPU frequency drivers from loading when booting under Xen
(as we want the Xen ACPI processor to be used instead).
* Cleanups in tmem code.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
iQEcBAABAgAGBQJPbc3DAAoJEFjIrFwIi8fJTQkIAMnH2fPhcHAb4mNaz+3gdmsZ
Flo6V1gMBcO8xKZlUkFgKKPYoOm7lLmvoceXLVSH5oOKSnSJo1zSinzKmcdJQo/D
kPo4/EguNwtzcAcQh2dmT6/IM9O3ihMKUli7Oajif9PLCFFFqTaG3Y3YNBo/rxTY
D3HAnJrIfmIyG0NpLnaFCWhCzUvcB4M7ysutECqcF8l5gnbHxRVeCKD0blM+n9GH
Wyum00dQCwo6h6wTduhPOAxHAM4rncyR3heOB2vDxq9YJHSUhhcva5QCgQ+tdUVt
6U2TQT1L2Px8iXXzr2w9YBpepOVajZReoKhajLjJ5VbkpBZFz5dVNfJ8LpF8RV8=
=z8IB
-----END PGP SIGNATURE-----
Merge tag 'stable/for-linus-3.4-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
Pull more xen updates from Konrad Rzeszutek Wilk:
"One tiny feature that accidentally got lost in the initial git pull:
* Add fast-EOI acking of interrupts (clear a bit instead of
hypercall)
And bug-fixes:
* Fix CPU bring-up code missing a call to notify other subsystems.
* Fix reading /sys/hypervisor even if PVonHVM drivers are not loaded.
* In Xen ACPI processor driver: remove too verbose WARN messages, fix
up the Kconfig dependency to be a module by default, and add
dependency on CPU_FREQ.
* Disable CPU frequency drivers from loading when booting under Xen
(as we want the Xen ACPI processor to be used instead).
* Cleanups in tmem code."
* tag 'stable/for-linus-3.4-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/acpi: Fix Kconfig dependency on CPU_FREQ
xen: initialize platform-pci even if xen_emul_unplug=never
xen/smp: Fix bringup bug in AP code.
xen/acpi: Remove the WARN's as they just create noise.
xen/tmem: cleanup
xen: support pirq_eoi_map
xen/acpi-processor: Do not depend on CPU frequency scaling drivers.
xen/cpufreq: Disable the cpu frequency scaling drivers from loading.
provide disable_cpufreq() function to disable the API.
Use 'bool' for boolean variables. Do proper section placement.
Eliminate an unnecessary export.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Complete the renaming from "flush" to "invalidate" across
both tmem frontends (cleancache and frontswap) and both tmem backends
(Xen and zcache), as required by akpm.
This change is completely cosmetic.
[v10: no change]
[v9: akpm@linux-foundation.org: change "flush" to "invalidate", part 3]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jan Beulich <JBeulich@novell.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Rik Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
[v11: Remove the frontswap part]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Provide the shim code for frontswap for Xen tmem even if the
frontswap patchset is not present yet. (The egg is before
the chicken.)
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Konrad Wilk <konrad.wilk@oracle.com>
This patch provides a shim between the kernel-internal cleancache
API (see Documentation/mm/cleancache.txt) and the Xen Transcendent
Memory ABI (see http://oss.oracle.com/projects/tmem).
Xen tmem provides "hypervisor RAM" as an ephemeral page-oriented
pseudo-RAM store for cleancache pages, shared cleancache pages,
and frontswap pages. Tmem provides enterprise-quality concurrency,
full save/restore and live migration support, compression
and deduplication.
A presentation showing up to 8% faster performance and up to 52%
reduction in sectors read on a kernel compile workload, despite
aggressive in-kernel page reclamation ("self-ballooning") can be
found at:
http://oss.oracle.com/projects/tmem/dist/documentation/presentations/TranscendentMemoryXenSummit2010.pdf
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>
