On Fri, Jan 11, 2019 at 12:55:38PM -0300, Arnaldo Carvalho de Melo wrote: > Hi Peter, > > bpf_perf_event_open() already returns a value, but if > perf_event_output's output_begin (mostly perf_output_begin) fails, > the only way to know about that is looking before/after the rb->lost, > right? > > For ring buffer users that is ok, we'll get a PERF_RECORD_LOST, > etc, but for BPF programs it would be convenient to get that -ENOSPC and > do some fallback, whatever makes sense, like in my augmented_syscalls > stuff for 'perf trace', i.e. don't augment it (i.e. push stuff at the > end of the normal payload), just don't filter the > raw_syscalls:sys_enter, 'perf trace' will get the enter syscall enter > event without the pointer dereference at the end, etc, warn the user but > don't lose a syscall in the strace-like output. > > What do you think? Am I missing something? Probably ;-)
Seems ok to do this.
