reached end of a block of journal items or read all of journal items. lfjour_cleanup_hook() can clean only journal items every recipient has processed,
so it was often called uselessly.
This commit restricts most of the unusefull scheduling. Only some consumers are given a token alowing them to try to schedule the lfjour_cleanup_hook().
When a consumer wants to schedule the lfjour_cleanup_hook(), it checks whether it has a token. If yes, it decrements number of tokens the journal has given (issued_tokens)
and discards its own token. If issued_tokens reaches zero, the consumer is allowed do schedule the lfjour_cleanup_hook().
There is a maximum number of tokens a journal can give to its customers (max_tokens). A new customer is given a token in its init, if the maximum number of tokens was not reached.
The rest of tokens is given to customers in lfjour_cleanup_hook(). In lf_jour_cleanup_hook(), it is increased the issued_tokens number in order not to call the hook
before it finishes. Then, tokens are given to the slowest recipients (but never to more than max_token recipients). Before leaving lfjour_cleanup_hook(),
the issued_tokens number is decreased. If no other tokens are given, we have to make sure the lfjour_cleanup_hook will be called again. If every item in journal
was read by every recipient, tokens are given to random recipients. If all recipients with tokens managed to finish until now, we give the token to first
unfinished customer we find or we call the hook again.
Instead of several levels of functions, just have two functions
(one for routes, the other for end-of-rib), this allows to create
messages in a simple linear fashion.
Also reduce three duplicite functions to construct BGP header for
BMP messages to just one.
This commit is quite a substantial rework of the underlying layers in
BMP TX:
- several unnecessary layers of indirection dropped, including most of
the original BMP's buffer machinery
- all messages are now written directly into one protocol's buffer
allocated for the whole time big enough to fit every possible message
- output blocks are allocated by pages and immediately returned when
used, improving the overall memory footprint
- no intermediary allocation is done from the heap altogether
- there is a documented and configurable limit on the TX queue size
Actually, completely rewritten the original patch as in v3, the logging
initialization is much more complex and requires allocation.
This way, to bootstrap properly, the logger has a pre-defined log target
to stderr.
We shouldn't convert bytes 2 and 3 of the PDU blindly, there are several
cases where these are used by bytes. Instead, the conversion is done
only where needed.
This fixes misinterpretation bug of ASPA PDU flags on little endian
architectures.
