cps: don't wait for routing daemons to make progress#484
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AltraMayor merged 6 commits intomasterfrom Jun 4, 2021
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The code that supports routing daemons used to live in cps/kni.c. This patch moves this code to the new file cps/rd.c. This move splits cps/kni.c into two files about even in the number of lines. The file cps/kni.c had more tahn 2K linas before this patch.
Library CORO implements coroutines.
In order to list the routing table for routing daemons, the CPS block needs to acquire a spin lock. This patch yields the coroutine, so the CPS block goes and does something instead of busy wait for the lock.
The system call sendto() may block for quite a while when a routing daemon is busy. This patch tests if calling sendto() is going to block, if so, it yields to other activities.
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Tested in production. |
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The code of the CPS block that communicates with routing daemon via rtnetlink(7) may wait for routing daemons to receive large replies (e.g. dumping a large routing table) in order to make progress. This wait disrupts the CPS block, which not only is expected to serve the rtnetlink interface, but also the KNI interfaces, and internal messages via its mailbox.
This pull request moves the rtnetlink code in the CPS block into a coroutine. Thus, whenever a wait is needed, the coroutine yields the control to the other activities that the CPS block is responsible for.