Pulp

The tasking system should be able to allow resources to be shared between tasks if only read access is requested.

The following design should allow to implement this without a migration and in a backwards compatible way:

• reuse the reserved_resources_record ListField shared resources will be prefixed by "shared:" exclusive resources will be used as is
• dispatch will add another parameter "shared_resources" in a backwards compatible way
• workers will augment the list of in_use_resources with a flag if any previous task requested a resource exclusive

Note: shared access that was scheduled after exclusive access still needs to wait. That is, one task requesting exclusive access to a resource will introduce a barrier for all other tasks requesting the same resource in any way.

https://hackmd.io/Y0l9nBm9SFmPiIBXBz8lwQ?view#Idea-Example-with-shared-and-exclusive-locks