> On Jan. 7, 2020, 9:43 p.m., Greg Mann wrote:
> > src/slave/slave.cpp
> > Lines 3623 (patched)
> > <https://reviews.apache.org/r/71858/diff/4/?file=2191535#file2191535line3628>
> >
> > Should this be an `Option`? So that we can only set
> > `containerConfig.limits` when limits have actually been set?
>
> Qian Zhang wrote:
> I added a check `if (!executorLimits.empty()) {` before setting
> `containerConfig.limit`, HDYT?
>
> Greg Mann wrote:
> If we use an option, then the type in the function signature more
> precisely expresses the semantics of the function, which improves readability
> IMO.
>
> Qian Zhang wrote:
> I actually thought about it before, but it may make the code a bit more
> complicated. Here is the code where we call `launchExecutor()`:
> ```
> defer(
> self(),
> &Self::launchExecutor,
> lambda::_1,
> frameworkId,
> executorInfo_,
> executorLimits,
> taskGroup.isNone() ? task.get() : Option<TaskInfo>::none()));
> ```
>
> The type of the variable `executorLimits` is `google::protobuf::Map`
> rather than `Option<google::protobuf::Map>`. So if we change the type of the
> parameter `executorLimits` of the `launchExecutor` method to
> `Option<google::protobuf::Map>`, its `isSome()` will actually always be true
> since a map `executorLimits` will always be passed to it, that means checking
> `executorLimits.isSome()` in `launchExecutor` is actually redundant. To make
> it not redundant, I may need to change the type of the variable
> `executorLimits` from `google::protobuf::Map` to
> `Option<google::protobuf::Map>`in the caller's code and define another local
> variable of type `google::protobuf::Map` and set `executorLimits` to that
> variable when we need to set executor's resource limits, I think it is bit
> more complicated than the current code in this patch.
>
> Another option would be set the default value of the `executorLimits`
> parameter to an empty map (i.e. `{}`), like:
> ```
> const google::protobuf::Map<string, Value::Scalar>& executorLimits = {},
> ```
> Does it help?
>
> Qian Zhang wrote:
> The reason that I did not set the default value of the `executorLimits`
> parameter to `{}` is, the variable `executorLimits` in the caller side is
> `{}` by default :-)
>
> Greg Mann wrote:
> > To make it not redundant, I may need to change the type of the variable
> executorLimits from google::protobuf::Map to Option\<google::protobuf::Map>in
> the caller's code and define another local variable of type
> google::protobuf::Map and set executorLimits to that variable when we need to
> set executor's resource limits
>
> Personally, that approach sounds better to me. I might be missing
> something, but this seems like a classic use case for the `Option` type.
>
> Qian Zhang wrote:
> I think the classic use case for the `Option` type is like:
> ```
> Option<int> var;
> if (...) {
> var = <An int value>
> }
> ```
>
> But here with the `Option` type, the code will be something like:
> ```
> Option<Map> executorLimits;
> Map executorLimits_;
>
> if (executorCpuLimit.isSome()) {
> executorLimits_.insert({"cpus", executorCpuLimit.get()});
> }
>
> if (executorMemLimit.isSome()) {
> executorLimits_.insert({"mem", executorMemLimit.get()});
> }
>
> if (!executorLimits_.empty()) {
> executorLimits = executorLimits_;
> }
>
> ```
>
> The above code is a bit redundant to me, I think the code like the below
> is better:
> ```
> Map executorLimits;
>
> if (executorCpuLimit.isSome()) {
> executorLimits.insert({"cpus", executorCpuLimit.get()});
> }
>
> if (executorMemLimit.isSome()) {
> executorLimits.insert({"mem", executorMemLimit.get()});
> }
> ```
Ah, this is related to my other comment about refactoring L3140 to L3201 :)
If we used an `Option` and refactored as I proposed, and if we will always set
the CPU and mem hard limits together (i.e. never set just CPU hard limits but
not mem hard limits), then we could do something like:
```
foreach (const TaskInfo& task, tasks) {
if (!task.limits().empty()) {
return true;
}
}
return false;
};
Option<Map<string, Value::Scalar>> executorLimits;
if (limitsAreSet(tasks)) {
executorLimitsResult = Map<string, Value::Scalar>(
{"cpus": Value::Scalar(),
"mem": Value::Scalar()});
foreach (const TaskInfo& _task, tasks) {
if (_task.limits().count("cpus")) {
executorLimitsResult.at("cpus") += _task.limits().at("cpus");
} else {
Option<Value::Scalar> taskCpus =
Resources(_task.resources()).get<Value::Scalar>("cpus");
if (taskCpus.isSome()) {
executorLimitsResult.at("cpus") += taskCpus.get();
}
}
if (_task.limits().count("mem")) {
executorLimitsResult.at("mem") += _task.limits().at("mem");
} else {
Option<Value::Scalar> taskMem =
Resources(_task.resources()).get<Value::Scalar>("mem");
if (taskMem.isSome()) {
executorLimitsResult.at("mem") += taskMem.get();
}
}
}
executorLimits = executorLimitsResult;
}
// Launch executor with 'executorLimits'...
```
WDYT?
- Greg
-----------------------------------------------------------
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https://reviews.apache.org/r/71858/#review219154
-----------------------------------------------------------
On Jan. 8, 2020, 2:40 a.m., Qian Zhang wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/71858/
> -----------------------------------------------------------
>
> (Updated Jan. 8, 2020, 2:40 a.m.)
>
>
> Review request for mesos, Andrei Budnik and Greg Mann.
>
>
> Bugs: MESOS-10046
> https://issues.apache.org/jira/browse/MESOS-10046
>
>
> Repository: mesos
>
>
> Description
> -------
>
> WIP: Set resource limits when launching executor container.
>
>
> Diffs
> -----
>
> src/slave/slave.hpp 77b5bc0082c6bb73fbd48a2ebe812629921645cb
> src/slave/slave.cpp 3839a120446339fea8aa857f431a2dba28ed4002
>
>
> Diff: https://reviews.apache.org/r/71858/diff/6/
>
>
> Testing
> -------
>
>
> Thanks,
>
> Qian Zhang
>
>
