FWIW: While I'm not the best at naming things, it would seem to me that this should be named "Nowait" rather than "Instant". On 06/07/2018 07:59 AM, Michal Privoznik wrote:
The aim of this API is to allow caller do best effort. Some
s/allow caller/allow the caller/ s/do best effort/to avoid waiting for a domain job if the domain is running something else that could take a long time./
functions of ours can work even when acquiring job fails (e.g.
s/of ours// s/job/the job/
qemuConnectGetAllDomainStats()). But what they can't bear is delay if they have to wait up to 30 seconds for each domain.
s/./that is processing some other job./
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_domain.c | 30 +++++++++++++++++++++++++----- src/qemu/qemu_domain.h | 4 ++++ 2 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 5273ab56ac..9657573342 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -6340,11 +6340,15 @@ qemuDomainJobAllowed(qemuDomainObjPrivatePtr priv, qemuDomainJob job) * @obj: domain object * @job: qemuDomainJob to start * @asyncJob: qemuDomainAsyncJob to start + * @instant: don't wait trying to acquire @job
Prefer "nowait" (or some camelCase version of that)
* * Acquires job over domain object which must be locked before * calling. If there's already a job running waits up to * QEMU_JOB_WAIT_TIME after which the functions fails reporting - * an error. + * an error unless @instant is set. + * If @instant is true this function tries to acquire job and if + * it fails returns immediately without waiting. No error is
s/it fails returns/it fails, then it returns/
+ * reported in this case.
Hmm... no error reported - meaning if ret = -1 and use this flag, it's up to the caller to generate the error... For this series, perhaps fine, but someone else using this, perhaps not.
* * Returns: 0 on success, * -2 if unable to start job because of timeout or @@ -6355,7 +6359,8 @@ static int ATTRIBUTE_NONNULL(1) qemuDomainObjBeginJobInternal(virQEMUDriverPtr driver, virDomainObjPtr obj, qemuDomainJob job, - qemuDomainAsyncJob asyncJob) + qemuDomainAsyncJob asyncJob, + bool instant) { qemuDomainObjPrivatePtr priv = obj->privateData; unsigned long long now; @@ -6395,12 +6400,18 @@ qemuDomainObjBeginJobInternal(virQEMUDriverPtr driver, }
while (!nested && !qemuDomainNestedJobAllowed(priv, job)) { + if (instant) + goto cleanup; +
If async is not supported for this (as I believe seen in the new API), then is this path possible?
VIR_DEBUG("Waiting for async job (vm=%p name=%s)", obj, obj->def->name); if (virCondWaitUntil(&priv->job.asyncCond, &obj->parent.lock, then) < 0) goto error; }
while (priv->job.active) { + if (instant) + goto cleanup; + VIR_DEBUG("Waiting for job (vm=%p name=%s)", obj, obj->def->name); if (virCondWaitUntil(&priv->job.cond, &obj->parent.lock, then) < 0) goto error; @@ -6517,7 +6528,7 @@ int qemuDomainObjBeginJob(virQEMUDriverPtr driver, qemuDomainJob job) { if (qemuDomainObjBeginJobInternal(driver, obj, job, - QEMU_ASYNC_JOB_NONE) < 0) + QEMU_ASYNC_JOB_NONE, false) < 0) return -1; else return 0; @@ -6532,7 +6543,7 @@ int qemuDomainObjBeginAsyncJob(virQEMUDriverPtr driver, qemuDomainObjPrivatePtr priv;
if (qemuDomainObjBeginJobInternal(driver, obj, QEMU_JOB_ASYNC, - asyncJob) < 0) + asyncJob, false) < 0) return -1;
priv = obj->privateData; @@ -6561,9 +6572,18 @@ qemuDomainObjBeginNestedJob(virQEMUDriverPtr driver,
return qemuDomainObjBeginJobInternal(driver, obj, QEMU_JOB_ASYNC_NESTED, - QEMU_ASYNC_JOB_NONE); + QEMU_ASYNC_JOB_NONE, + false); }
+int +qemuDomainObjBeginJobInstant(virQEMUDriverPtr driver, + virDomainObjPtr obj, + qemuDomainJob job) +{ + return qemuDomainObjBeginJobInternal(driver, obj, job, + QEMU_ASYNC_JOB_NONE, true);
^^^^^^^^^^^^^^^^^^^^ Doesn't this mean async jobs are not supported. John
+}
/* * obj must be locked and have a reference before calling diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index f17157b951..4b63c00dff 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -512,6 +512,10 @@ int qemuDomainObjBeginNestedJob(virQEMUDriverPtr driver, virDomainObjPtr obj, qemuDomainAsyncJob asyncJob) ATTRIBUTE_RETURN_CHECK; +int qemuDomainObjBeginJobInstant(virQEMUDriverPtr driver, + virDomainObjPtr obj, + qemuDomainJob job) + ATTRIBUTE_RETURN_CHECK;
void qemuDomainObjEndJob(virQEMUDriverPtr driver, virDomainObjPtr obj);