Re: CPU Concurrency Issues
Matt Ahrens
On Mon, Aug 19, 2019 at 4:30 PM Yonghong Song <ys114321@...> wrote: On Mon, Aug 19, 2019 at 1:54 PM <brad.lewis@...> wrote: When running bpf code from a kprobe / kretprobe, does anything ensure that cpu_id doesn't change while the bpf is running (e.g. due to preemption)? Does anything ensure that no other bpf code runs on this CPU while this kprobe is running (e.g. due to an interrupt firing and hitting a different kprobe)? If either of those things can happen, it seems difficult to atomically increment an entry in a HASH_MAP (even when using the cpu_id as a key). --matt
|
|