We can do with a forward declaration instead to reduce
the dependency, and include reader_concurrency_semaphore.hh
in test/lib/reader_permit.cc instead.
We need to include "../../reader_permit.hh" to get the
definition of class reader_permit. We need the include
path to prevent recursive include (or rename test/lib/reader_permit.hh
but this creates a lot of code churn).
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20210204122002.1041808-1-bhalevy@scylladb.com>
Require a schema and an operation name to be given to each permit when
created. The schema is of the table the read is executed against, and
the operation name, which is some name identifying the operation the
permit is part of. Ideally this should be different for each site the
permit is created at, to be able to discern not only different kind of
reads, but different code paths the read took.
As not all read can be associated with one schema, the schema is allowed
to be null.
The name will be used for debugging purposes, both for coredump
debugging and runtime logging of permit-related diagnostics.
We want to switch from using a single limit to a dual soft/hard limit.
As a first step we switch the limit field of `query_class_config` to use
the recently introduced type for this. As this field has a single user
at the moment -- reverse queries (and not a lot of propagation) -- we
update it in this same patch to use the soft/hard limit: warn on
reaching the soft limit and abort on the hard limit (the previous
behaviour).
This contains a reader concurrency semaphore for the tests, that they
can use to obtain a valid permit for reads. Soon we are going to start
working towards a point where all APIs taking a permit will require a
valid one. Before we start this work we must ensure test code is able to
obtain a valid permit.
