Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

config-linux: add memory.checkBeforeUpdate #1158

Merged
merged 1 commit into from
Sep 9, 2022
Merged

config-linux: add memory.checkBeforeUpdate #1158

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions config-linux.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -336,6 +336,11 @@ The following properties do not specify memory limits, but are covered by the `m
To disable it, specify a value of `true`.
* **`useHierarchy`** *(bool, OPTIONAL)* - enables or disables hierarchical memory accounting.
If enabled (`true`), child cgroups will share the memory limits of this cgroup.
* **`checkBeforeUpdate`** *(bool, OPTIONAL)* - enables container memory usage check before setting a new limit.
giuseppe marked this conversation as resolved.
Show resolved Hide resolved
If enabled (`true`), runtime MAY check if a new memory limit is lower than the current usage, and MUST
reject the new limit. Practically, when cgroup v1 is used, the kernel rejects the limit lower than the
current usage, and when cgroup v2 is used, an OOM killer is invoked. This setting can be used on
cgroup v2 to mimic the cgroup v1 behavior.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Should we call out that there is TOCTOU race possible here and it won't be able to exactly match cgroups v1 behavior?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

To me this is an implementation detail, and this is merely a spec. In fact it should not even explain why we need it, but I guess some context would not hurt.


#### Example

Expand Down
3 changes: 3 additions & 0 deletions schema/config-linux.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -169,6 +169,9 @@
},
"useHierarchy": {
"type": "boolean"
},
"checkBeforeUpdate": {
"type": "boolean"
}
}
},
Expand Down
3 changes: 2 additions & 1 deletion schema/test/config/good/spec-example.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -270,7 +270,8 @@
"kernelTCP": -1,
"swappiness": 0,
"disableOOMKiller": false,
"useHierarchy": false
"useHierarchy": false,
"checkBeforeUpdate": false
},
"cpu": {
"shares": 1024,
Expand Down
4 changes: 4 additions & 0 deletions specs-go/config.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -319,6 +319,10 @@ type LinuxMemory struct {
DisableOOMKiller *bool `json:"disableOOMKiller,omitempty"`
// Enables hierarchical memory accounting
UseHierarchy *bool `json:"useHierarchy,omitempty"`
// CheckBeforeUpdate enables checking if a new memory limit is lower
// than the current usage during update, and if so, rejecting the new
// limit.
CheckBeforeUpdate *bool `json:"checkBeforeUpdate,omitempty"`
}

// LinuxCPU for Linux cgroup 'cpu' resource management
Expand Down