Later, a mechanism to set a limit on how much memory may be used for the overlap prevention structures will be introduced. If that limit is about to be exceeded, a QMP event should be emitted. This very event is specified by this patch.
Signed-off-by: Max Reitz <mre...@redhat.com> --- docs/qmp/qmp-events.txt | 28 ++++++++++++++++++++++++++++ qapi/event.json | 27 +++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt index b19e490..4ec257e 100644 --- a/docs/qmp/qmp-events.txt +++ b/docs/qmp/qmp-events.txt @@ -261,6 +261,34 @@ Example: { "event": "POWERDOWN", "timestamp": { "seconds": 1267040730, "microseconds": 682951 } } +QCOW2_OVERLAP_CHECK_MEMORY_LIMIT_REACHED +---------------------------------------- + +Emitted by the qcow2 block driver if the preset size limit for the in-memory +structures for metadata overlap prevention has been reached and an allocation +of further resources has been denied. This means that it cannot be guaranteed +that overlap checks will be performed for the specified range; if no range is +given, no checks can be expected to be performed whatsoever. + +Note that this event does not guarantee that no check will be performed in the +given range (or on the whole image, if no range is given), but only signals the +possibility that this might be the case. The ability to check the full range or +a part of it may be restored at any point in time. + +Data: +- "reference": Device name if set; node name otherwise. (json-string) +- "start": Offset of the range of clusters (possibly) no longer being + checked for writes overlapping with existing metadata. + (json-int, optional) +- "length": Length of that range in bytes. (json-int, optional) + +Example: + +{ "event": "QCOW2_OVERLAP_CHECK_MEMORY_LIMIT_REACHED", + "data": { "reference": "virtio0", "start": "805306368", + "length": "268435456" }, + "timestamp": { "seconds": 1429331400, "microseconds": 519454 } } + QUORUM_FAILURE -------------- diff --git a/qapi/event.json b/qapi/event.json index c51dc49..a6cd053 100644 --- a/qapi/event.json +++ b/qapi/event.json @@ -330,3 +330,30 @@ ## { 'event': 'VSERPORT_CHANGE', 'data': { 'id': 'str', 'open': 'bool' } } + +## +# @QCOW2_OVERLAP_CHECK_MEMORY_LIMIT_REACHED +# +# Emitted by the qcow2 block driver if the preset size limit for the in-memory +# structures for metadata overlap prevention has been reached and an allocation +# of further resources has been denied. This means that no overlap checks will +# be performed for the specified range. +# +# Note that this event does not guarantee that no check will be performed in the +# given range (or on the whole image, if no range is given), but only signals +# the possibility that this might be the case. The ability to check the full +# range or a part of it may be restored at any point in time. +# +# @reference: device name if set; node name otherwise +# +# @start: #optional offset of the range of clusters (possibly) no longer +# being checked for writes overlapping with existing metadata +# +# @length: #optional length of that range in bytes +# +# Since: 2.4 +## +{ 'event': 'QCOW2_OVERLAP_CHECK_MEMORY_LIMIT_REACHED', + 'data': { 'reference': 'str', + '*start': 'int', + '*length': 'int' } } -- 2.3.7