Dear eBPF community
If I understand correctly, per_cpu maps are meant to avoid threading issues, and for example the need to call BPF_XADD to keep counters safe. There is something I am unclear about: - Is it possible for a BPF program to be preempted by another BPF program on the same CPU? If this is the case, it seems that the following scenario could arise: BPF program 1 on cpu 0 reads a counter and is preempted before incrementing it BPF program 2 on cpu 0 reads the same counter, increments it, and finishes BPF program 1 on cpu 0 increments the counter At which point both programs would have read the same value for the counter, with possible problems ensuing. Is this a valid scenario? Am I missing something about how the per_cpu maps are intended to be used? Thanks Pablo Alvarez -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#1531): https://lists.iovisor.org/g/iovisor-dev/message/1531 Mute This Topic: https://lists.iovisor.org/mt/28471975/21656 Group Owner: iovisor-dev+ow...@lists.iovisor.org Unsubscribe: https://lists.iovisor.org/g/iovisor-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
