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2012-06-15Add event notification for guest balloon changesDaniel P. Berrange
After setting a balloon target value, applications have to continually poll 'query-balloon' to determine whether the guest has reacted to this request. The virtio-balloon backend knows exactly when the guest has reacted though, and thus it is possible to emit a JSON event to tell the mgmt application whenever the guest balloon changes. This introduces a new 'qemu_balloon_changed()' API which is to be called by balloon driver backends, whenever they have a change in balloon value. This takes the 'actual' balloon value, as would be found in the BalloonInfo struct. The qemu_balloon_change API emits a JSON monitor event which looks like: {"timestamp": {"seconds": 1337162462, "microseconds": 814521}, "event": "BALLOON_CHANGE", "data": {"actual": 944766976}} * balloon.c, balloon.h: Introduce qemu_balloon_changed() for emitting balloon change events on the monitor * hw/virtio-balloon.c: Invoke qemu_balloon_changed() whenever the guest changes the balloon actual value * monitor.c, monitor.h: Define QEVENT_BALLOON_CHANGE Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Acked-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-12-06qapi: Convert balloonLuiz Capitulino
Note that the command being dropped uses the deprecated MONITOR_CMD_ASYNC API, but the new command is a regular synchronous command. There shouldn't be visible differences though, as MONITOR_CMD_ASYNC is internal only. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-10-27qapi: Convert query-balloonLuiz Capitulino
Please, note that some of the code supporting memory statistics is still around (eg. virtio_balloon_receive_stats() and reset_stats()). Also, the qmp_query_balloon() function is synchronous and thus doesn't make any use of the (not fully working) monitor's asynchronous command support (the old non-qapi implementation did). Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-09-09balloon: Disassociate handlers from balloon device on unplugAmit Shah
When a balloon device gets unplugged, allow the balloon handlers to be freed. Reported-by: Shaolong Hu <shu@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-04balloon: Don't allow multiple balloon handler registrationsAmit Shah
Multiple balloon devices don't make sense; disallow more than one registration attempt to register handlers. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2011-08-04balloon: Separate out stat and balloon handlingAmit Shah
Passing on '0' as ballooning target to indicate retrieval of stats is bad API. It also makes 'balloon 0' in the monitor cause a segfault. Have two different functions handle the different functionality instead. Detailed explanation from Markus's review: 1. do_info_balloon() is an info_async() method. It receives a callback with argument, to be called exactly once (callback frees the argument). It passes the callback via qemu_balloon_status() and indirectly through qemu_balloon_event to virtio_balloon_to_target(). virtio_balloon_to_target() executes its balloon stats half. It stores the callback in the device state. If it can't send a stats request, it resets stats and calls the callback right away. Else, it sends a stats request. The device model runs the callback when it receives the answer. Works. 2. do_balloon() is a cmd_async() method. It receives a callback with argument, to be called when the command completes. do_balloon() calls it right before it succeeds. Odd, but should work. Nevertheless, it passes the callback on via qemu_ballon() and indirectly through qemu_balloon_event to virtio_balloon_to_target(). a. If the argument is non-zero, virtio_balloon_to_target() executes its balloon half, which doesn't use the callback in any way. Odd, but works. b. If the argument is zero, virtio_balloon_to_target() executes its balloon stats half, just like in 1. It either calls the callback right away, or arranges for it to be called later. Thus, the callback runs twice: use after free and double free. Test case: start with -S -device virtio-balloon, execute "balloon 0" in human monitor. Runs the callback first from virtio_balloon_to_target(), then again from do_balloon(). Reported-by: Mike Cao <bcao@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com>
2011-08-04balloon: Make functions, local vars staticAmit Shah
balloon.h had function declarations for a couple of functions that are local to balloon.c. Make them static. Drop the 'qemu_' prefix for balloon.c-local variables, and make them static. Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com>
2010-04-09move balloon handling to balloon.cPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
2010-03-29Allow various header files to be included from non-CPU codeBlue Swirl
Allow balloon.h, gdbstub.h and kvm.h to be included from non-CPU code. Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-01-26virtio: Add memory statistics reporting to the balloon driverAdam Litke
When using ballooning to manage overcommitted memory on a host, a system for guests to communicate their memory usage to the host can provide information that will minimize the impact of ballooning on the guests. The current method employs a daemon running in each guest that communicates memory statistics to a host daemon at a specified time interval. The host daemon aggregates this information and inflates and/or deflates balloons according to the level of host memory pressure. This approach is effective but overly complex since a daemon must be installed inside each guest and coordinated to communicate with the host. A simpler approach is to collect memory statistics in the virtio balloon driver and communicate them directly to the hypervisor. Signed-off-by: Adam Litke <agl@us.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-10-01Revert "Get rid of _t suffix"Anthony Liguori
In the very least, a change like this requires discussion on the list. The naming convention is goofy and it causes a massive merge problem. Something like this _must_ be presented on the list first so people can provide input and cope with it. This reverts commit 99a0949b720a0936da2052cb9a46db04ffc6db29. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-10-01Get rid of _t suffixmalc
Some not so obvious bits, slirp and Xen were left alone for the time being. Signed-off-by: malc <av1474@comtv.ru>
2008-12-04Add missing file from previous commit.aliguori
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5875 c046a42c-6fe2-441c-8c8c-71466251a162