Merge pull request #1279 from cyphar/pids-limit-0-value

linux: clarify pids cgroup settings

Author: AkihiroSuda

config-linux.md

@@ -666,7 +666,9 @@ For more information, see the kernel cgroups documentation about [pids][cgroup-v
 
 The following parameters can be specified to set up the controller:
 
-* **`limit`** *(int64, REQUIRED)* - specifies the maximum number of tasks in the cgroup
+* **`limit`** *(int64, OPTIONAL)* - specifies the maximum number of tasks in the cgroup, with `-1` indicating no limit (`max`).
+
+> Note: Even though it may superficially seem redundant, `0` is a valid limit value for the `pids` cgroup controller from the kernel's perspective and SHOULD be treated as such by runtimes.
 
 #### Example
 

specs-go/config.go

@@ -434,7 +434,7 @@ type LinuxCPU struct {
 // LinuxPids for Linux cgroup 'pids' resource management (Linux 4.3)
 type LinuxPids struct {
 	// Maximum number of PIDs. Default is "no limit".
-	Limit int64 `json:"limit"`
+	Limit *int64 `json:"limit,omitempty"`
 }
 
 // LinuxNetwork identification and priority configuration