Hi! Lately we started to write BPF testcases for LTP and after writing a first few tests we found out that running more than a few in a row causes them to fail with EPERM. The culprit is deferred cleanup of the bpf maps that are locked in the memory, see: http://lists.linux.it/pipermail/ltp/2019-August/013349.html We worked around that by bumping the limit for the tests in: https://github.com/linux-test-project/ltp/commit/85c4e886b357f7844f6ab8ec5719168c38703a76 But it looks like this value will not scale, especially for architectures that have larger than 4k pages, running four BPF tests in a row still fails on ppc64le even with the increased limit. Perhaps I'm naive but can't we check, in the kernel, if there is deferred cleanup in progress if we fail to lock memory for a map and retry once it's done? Or is this intended behavior and should we retry on EPERM in userspace? -- Cyril Hrubis chrubis@xxxxxxx
