On Mon, 29 Jun 2020 22:16:59 -0700 Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote:
> > > > Warning, not even compiled tested. > > Thanks! I see what you mean now. Great! :-) > > > > > -- Steve > > > > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > > index 6575bb0a0434..aeba5ee7325a 100644 > > --- a/kernel/trace/Makefile > > +++ b/kernel/trace/Makefile > > @@ -31,6 +31,8 @@ ifdef CONFIG_GCOV_PROFILE_FTRACE > > GCOV_PROFILE := y > > endif > > > > +CFLAGS_bpf_trace.o := -I$(src) > > not following. why this is needed? It's required in order to have the TRACE_EVENT macro magic work. More info about it here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/trace_events/Makefile > > > + > > CFLAGS_trace_benchmark.o := -I$(src) > > CFLAGS_trace_events_filter.o := -I$(src) > > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index dc05626979b8..01bedf335b2e 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -19,6 +19,9 @@ > > #include "trace_probe.h" > > #include "trace.h" > > > > +#define CREATE_TRACE_EVENTS > > CREATE_TRACE_POINTS ? Doh, yeah. I did say it wasn't even compiled tested ;-) > > > +#include "bpf_trace.h" > > + > > #define bpf_event_rcu_dereference(p) > > \ > > rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) > > > > @@ -473,13 +476,29 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, > > fmt_size, u64, arg1, > > fmt_cnt++; > > } > > > > +static DEFINE_SPINLOCK(trace_printk_lock); > > +#define BPF_TRACE_PRINTK_SIZE 1024 > > + > > +static inline void do_trace_printk(const char *fmt, ...) > > +{ > > + static char buf[BPF_TRACE_PRINT_SIZE]; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&trace_printk_lock, flags); > > + va_start(ap, fmt); > > + vsnprintf(buf, BPF_TRACE_PRINT_SIZE, fmt, ap); > > + va_end(ap); > > + > > + trace_bpf_trace_printk(buf); > > + spin_unlock_irqrestore(&trace_printk_lock, flags); > > interesting. I don't think anyone would care about spin_lock overhead. > It's better because 'trace_bpf_trace_printk' would be a separate event > that can be individually enabled/disabled? > I guess it can work. > Thanks! I hope this does everything you need for bpf_trace_printk. If there's something that's not working for you, PLEASE reach out to me and ask what you need. Cheers! -- Steve
