The thread pool regulates itself: when idle, it kills threads until
empty, when in demand, it creates new threads until full. This behaviour
doesn't play well with latency sensitive workloads where the price of
creating a new thread is too high. For example, when paired with qemu's
'-mlock', or using safety features like SafeStack, creating a new thread
has been measured take multiple milliseconds.
In order to mitigate this let's introduce a new 'EventLoopBase'
property to set the thread pool size. The threads will be created during
the pool's initialization or upon updating the property's value, remain
available during its lifetime regardless of demand, and destroyed upon
freeing it. A properly characterized workload will then be able to
configure the pool to avoid any latency spikes.
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20220425075723.20019-4-nsaenzju@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
'event-loop-base' provides basic property handling for all 'AioContext'
based event loops. So let's define a new 'MainLoopClass' that inherits
from it. This will permit tweaking the main loop's properties through
qapi as well as through the command line using the '-object' keyword[1].
Only one instance of 'MainLoopClass' might be created at any time.
'EventLoopBaseClass' learns a new callback, 'can_be_deleted()' so as to
mark 'MainLoop' as non-deletable.
[1] For example:
-object main-loop,id=main-loop,aio-max-batch=<value>
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20220425075723.20019-3-nsaenzju@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Introduce the 'event-loop-base' abstract class, it'll hold the
properties common to all event loops and provide the necessary hooks for
their creation and maintenance. Then have iothread inherit from it.
EventLoopBaseClass is defined as user creatable and provides a hook for
its children to attach themselves to the user creatable class 'complete'
function. It also provides an update_params() callback to propagate
property changes onto its children.
The new 'event-loop-base' class will live in the root directory. It is
built on its own using the 'link_whole' option (there are no direct
function dependencies between the class and its children, it all happens
trough 'constructor' magic). And also imposes new compilation
dependencies:
qom <- event-loop-base <- blockdev (iothread.c)
And in subsequent patches:
qom <- event-loop-base <- qemuutil (util/main-loop.c)
All this forced some amount of reordering in meson.build:
- Moved qom build definition before qemuutil. Doing it the other way
around (i.e. moving qemuutil after qom) isn't possible as a lot of
core libraries that live in between the two depend on it.
- Process the 'hw' subdir earlier, as it introduces files into the
'qom' source set.
No functional changes intended.
Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20220425075723.20019-2-nsaenzju@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Hi all! Current logic of relying on search through backing chain is not
safe neither convenient.
Sometimes it leads to necessity of extra bitmap copying. Also, we are
going to add "snapshot-access" driver, to access some snapshot state
through NBD. And this driver is not formally a filter, and of course
it's not a COW format driver. So, searching through backing chain will
not work. Instead of widening the workaround of bitmap searching, let's
extend the interface so that user can select bitmap precisely.
Note, that checking for bitmap active status is not copied to the new
API, I don't see a reason for it, user should understand the risks. And
anyway, bitmap from other node is unrelated to this export being
read-only or read-write.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
Message-Id: <20220314213226.362217-3-v.sementsov-og@mail.ru>
[eblake: Adjust S-o-b to Vladimir's new email, with permission]
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
'blockdev-change-medium' is a convinient wrapper for the following
sequence of commands:
* blockdev-open-tray
* blockdev-remove-medium
* blockdev-insert-medium
* blockdev-close-tray
and should be used f.e. to change ISO image inside the CD-ROM tray.
Though the guest could lock the tray and some linux guests like
CentOS 8.5 actually does that. In this case the execution if this
command results in the error like the following:
Device 'scsi0-0-1-0' is locked and force was not specified,
wait for tray to open and try again.
This situation is could be resolved 'blockdev-open-tray' by passing
flag 'force' inside. Thus is seems reasonable to add the same
capability for 'blockdev-change-medium' too.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
Acked-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220412221846.280723-1-den@openvz.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
QAPI patches patches for 2022-04-21
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# gpg: Signature made Thu 21 Apr 2022 07:11:14 AM PDT
# gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg: issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [undefined]
# gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [undefined]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653
* tag 'pull-qapi-2022-04-21' of git://repo.or.cz/qemu/armbru:
qapi: Fix version of cpu0-id field
qapi: Fix typo
qapi: Fix documentation for query-xen-replication-status
docs: qapi: Remove outdated reference to simple unions
qapi-schema: test: add a unit test for parsing array alternates
qapi-schema: test: add a qapi-schema-test for array alternates
qapi-schema: support alternates with array type
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add a new field 'cpu0-id' to the response of query-sev-capabilities QMP
command. The value of the field is the base64-encoded unique ID of CPU0
(socket 0), which can be used to retrieve the signed CEK of the CPU from
AMD's Key Distribution Service (KDS).
Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220228093014.882288-1-dovmurik@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Example output has the optional member @dnssearch as string type. It
should be an array of String objects instead. Fix it.
For reference, see NetdevUserOptions.
Signed-off-by: Victor Toso <victortoso@redhat.com>
Message-Id: <20220401110712.26911-1-victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked for precision]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Example output lacks mandatory member @timestamp. Provide it.
Example output lacks mandatory member flags.recursive. Provide it.
Minor: Change quotes from '' to "" in @action-required member.
Signed-off-by: Victor Toso <victortoso@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20220328140604.41484-12-victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message fixed up]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Example output lacks mandatory member @timestamp. Provide it.
Example output is not properly formatted. Fixing it by:
- Adding '<-' to signalize it is receiving the data;
- Breaking lines similar to the other examples.
Signed-off-by: Victor Toso <victortoso@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20220328140604.41484-8-victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Example output lacks mandatory member @timestamp. Provide it.
Example output is not properly formatted. Fixing it by:
- Adding '<-' to signalize it is receiving the data;
- Adding extra spaces around members @result, @total and @completed
Signed-off-by: Victor Toso <victortoso@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20220328140604.41484-6-victortoso@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
When switching between guest and host on a Mac using command-tab the
command key is sent to the guest which can trigger functionality in the
guest OS. Specifying left-command-key=off disables forwarding this key
to the guest. Defaults to enabled.
Also updated the cocoa display documentation to reference the new
left-command-key option along with the existing show-cursor option.
Signed-off-by: Carwyn Ellis <carwynellis@gmail.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@gmail.com>
[PMD: Set QAPI structure @since tag to 7.0]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
When connecting to an NBD server with TLS and x509 credentials,
the client must validate the hostname it uses for the connection,
against that published in the server's certificate. If the client
is tunnelling its connection over some other channel, however, the
hostname it uses may not match the info reported in the server's
certificate. In such a case, the user needs to explicitly set an
override for the hostname to use for certificate validation.
This is achieved by adding a 'tls-hostname' property to the NBD
block driver.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220304193610.3293146-4-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
The new block driver simply utilizes snapshot-access API of underlying
block node.
In further patches we want to use it like this:
[guest] [NBD export]
| |
| root | root
v file v
[copy-before-write]<------[snapshot-access]
| |
| file | target
v v
[active-disk] [temp.img]
This way, NBD client will be able to read snapshotted state of active
disk, when active disk is continued to be written by guest. This is
known as "fleecing", and currently uses another scheme based on qcow2
temporary image which backing file is active-disk. New scheme comes
with benefits - see next commit.
The other possible application is exporting internal snapshots of
qcow2, like this:
[guest] [NBD export]
| |
| root | root
v file v
[qcow2]<---------[snapshot-access]
For this, we'll need to implement snapshot-access API handlers in
qcow2 driver, and improve snapshot-access block driver (and API) to
make it possible to select snapshot by name. Another thing to improve
is size of snapshot. Now for simplicity we just use size of bs->file,
which is OK for backup, but for qcow2 snapshots export we'll need to
imporve snapshot-access API to get size of snapshot.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20220303194349.2304213-12-vsementsov@virtuozzo.com>
[hreitz: Rebased on block GS/IO split]
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
