So that internal iothread users can explicitly stop one iothread without
destroying it.
Since at it, fix iothread_stop() to allow it to be called multiple
times. Before this patch we may call iothread_stop() more than once on
single iothread, while that may not be correct since qemu_thread_join()
is not allowed to run twice. From manual of pthread_join():
Joining with a thread that has previously been joined results in
undefined behavior.
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20170928025958.1420-4-peterx@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
IOThread is a general framework that contains IO loop environment and a
real thread behind. It's also good to be used internally inside qemu.
Provide some helpers for it to create iothreads to be used internally.
Put all the internal used iothreads into the internal object container.
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20170928025958.1420-3-peterx@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
IOThread uses AioContext event loop and does not run a GMainContext.
Therefore,chardev cannot work in IOThread,such as the chardev is
used for colo-compare packets reception.
This patch makes the IOThread run the GMainContext event loop,
chardev and IOThread can work together.
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Wang Yong <wang.yong155@zte.com.cn>
Signed-off-by: Wang Guang <wang.guang55@zte.com.cn>
Signed-off-by: Jason Wang <jasowang@redhat.com>
These parameters control the poll time self-tuning algorithm. They are
optional and will default to sane values if omitted.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-14-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Poll mode can be configured with -object iothread,poll-max-ns=NUM.
Polling is disabled with a value of 0 nanoseconds.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-7-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Right after main_loop ends, we release various things but keep iothread
alive. The latter is not prepared to the sudden change of resources.
Specifically, after bdrv_close_all(), virtio-scsi dataplane get a
surprise at the empty BlockBackend:
(gdb) bt
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:543
at /usr/src/debug/qemu-2.6.0/hw/scsi/virtio-scsi.c:577
It is because the d->conf.blk->root is set to NULL, then
blk_get_aio_context() returns qemu_aio_context, whereas s->ctx is still
pointing to the iothread:
hw/scsi/virtio-scsi.c:543:
if (s->dataplane_started) {
assert(blk_get_aio_context(d->conf.blk) == s->ctx);
}
To fix this, let's stop iothreads before doing bdrv_close_all().
Cc: qemu-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1473326931-9699-1-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The functions tpm_backend_thread_tpm_reset() and iothread_find()
are completely unused, let's remove them.
Signed-off-by: Thomas Huth <huth@tuxfamily.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Make the IOThread struct definition public so objects can be embedded in
parent structs.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a stand-in for Michael Roth's QContext. I expect this to be
replaced once QContext is completed.
The IOThread object is an AioContext event loop thread. This patch adds
the concept of multiple event loop threads, allowing users to define
them.
When SMP guests run on SMP hosts it makes sense to instantiate multiple
IOThreads. This spreads event loop processing across multiple cores.
Note that additional patches are required to actually bind a device to
an IOThread.
[Andreas Färber <afaerber@suse.de> pointed out that the embedded parent
object instance should be called "parent_obj" and have a newline
afterwards. This patch has been changed to reflect this.
-- Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
