The emacs variable to set the C style from a local variable block is
c-file-style, not c-set-style.
Signed-off-by: David Vrabel <david.vrabel@citrix.com
xc_tmem.c: In function 'xc_tmem_restore':
xc_tmem.c:393:14: error: variable 'save_max_pools' set but not used
[-Werror=unused-but-set-variable]
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Not actually used here but useful to confirm that a handle is passed
down to each location where it will be required once we switch to
hypercall buffers.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
After a great deal of discussion and review with linux
kernel developers, it appears there are "next-generation"
filesystems (such as btrfs, xfs, Lustre) that will not
be able to use tmem due to an ABI limitation... a field
that represents a unique file identifier is 64-bits in
the tmem ABI and may need to be as large as 192-bits.
So to support these guest filesystems, the tmem ABI must be
revised, from "v0" to "v1".
I *think* it is still the case that tmem is experimental
and is not used anywhere yet in production.
The tmem ABI is designed to support multiple revisions,
so the Xen tmem implementation could be updated to
handle both v0 and v1. However this is a bit
messy and would require data structures for both v0
and v1 to appear in public Xen header files.
I am inclined to update the Xen tmem implementation
to only support v1 and gracefully fail v0. This would
result in only a performance loss (as if tmem were
disabled) for newly launched tmem-v0-enabled guests,
but live-migration between old tmem-v0 Xen and new
tmem-v1 Xen machines would fail, and saved tmem-v0
guests will not be able to be restored on a tmem-v1
Xen machine. I would plan to update both pre-4.0.2
and unstable (future 4.1) to only support v1.
I believe these restrictions are reasonable at this
point in the tmem lifecycle, though they may not
be reasonable in the near future; should the tmem
ABI need to be revised from v1 to v2, I understand
backwards compatibility will be required.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
# User Ian Campbell <ian.campbell@citrix.com>
# Date 1282671421 -3600
# Node ID d1dd29a470ef1b9d2c77478a123326036dfe90bb
# Parent d7a4adad9c328decbd384d87b23001aea8951b86
tools/libxc, tools/libelf: Relicense under LGPL v2.1
Relicense these two libraries under LGPL v2.1 only except where
individual files already included the "or later" provision.
Copyright holders have been contacted by Stephen Spector and have all
agreed this change.
Removed tools/libxc/ia64/aclinux.h since it appeared to be
unused. There is a separate, more up to date, copy in
xen/include/acpi/platform/aclinux.h which does appear to be used.
Clarify the license of MiniOS privcmd.h under the same terms as other
tools/include/xen-sys headers.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Stephen Spector <stephen.spector@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
This patch eliminate the global variables in libxenctrl (used for
logging and error reporting).
Instead the information which was in the global variables is now in a
new xc_interface* opaque structure, which xc_interface open returns
instead of the raw file descriptor; furthermore, logging is done via
xentoollog.
There are three new parameters to xc_interface_open to control the
logging, but existing callers can just pass "0" for all three to get
the old behaviour.
All libxc callers have been adjusted accordingly.
Also update QEMU_TAG for corresponding qemu change.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Attached patch implements save/restore/migration/livemigration
for transcendent memory ("tmem"). Without this patch, domains
using tmem may in some cases lose data when doing save/restore
or migrate/livemigrate. Also included in this patch is
support for a new (privileged) hypercall for authorizing
domains to share pools; this provides the foundation to
accomodate upstream linux requests for security for shared
pools.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
This implicitly required coverting the tmem_op structure from
anonymous to standard struct/union sub-fields, and extending the
get-fields.sh helper script to deal with typedef-ed guest handles used
as types of translated compound type fields.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Tmem, when called from a tmem-capable (paravirtualized) guest, makes
use of otherwise unutilized ("fallow") memory to create and manage
pools of pages that can be accessed from the guest either as
"ephemeral" pages or as "persistent" pages. In either case, the pages
are not directly addressible by the guest, only copied to and fro via
the tmem interface. Ephemeral pages are a nice place for a guest to
put recently evicted clean pages that it might need again; these pages
can be reclaimed synchronously by Xen for other guests or other uses.
Persistent pages are a nice place for a guest to put "swap" pages to
avoid sending them to disk. These pages retain data as long as the
guest lives, but count against the guest memory allocation.
Tmem pages may optionally be compressed and, in certain cases, can be
shared between guests. Tmem also handles concurrency nicely and
provides limited QoS settings to combat malicious DoS attempts.
Save/restore and live migration support is not yet provided.
Tmem is primarily targeted for an x86 64-bit hypervisor. On a 32-bit
x86 hypervisor, it has limited functionality and testing due to
limitations of the xen heap. Nearly all of tmem is
architecture-independent; three routines remain to be ported to ia64
and it should work on that architecture too. It is also structured to
be portable to non-Xen environments.
Tmem defaults off (for now) and must be enabled with a "tmem" xen boot
option (and does nothing unless a tmem-capable guest is running). The
"tmem_compress" boot option enables compression which takes about 10x
more CPU but approximately doubles the number of pages that can be
stored.
Tmem can be controlled via several "xm" commands and many interesting
tmem statistics can be obtained. A README and internal specification
will follow, but lots of useful prose about tmem, as well as Linux
patches, can be found at http://oss.oracle.com/projects/tmem .
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
David Vrabel
Olaf Hering
Keir Fraser
Ian Campbell
Keir Fraser