Re: [PATCH 1/2] locking: Add lock contention tracepoints

From: Steven Rostedt
Date: Thu Mar 17 2022 - 12:08:05 EST


On Thu, 17 Mar 2022 09:32:55 -0400 (EDT)
Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:

> Unless there is a particular reason for using preprocessor defines here, the
> following form is typically better because it does not pollute the preprocessor
> defines, e.g.:
>
> enum lock_contention_flags {
> LCB_F_SPIN = 1U << 0;
> LCB_F_READ = 1U << 1;
> LCB_F_WRITE = 1U << 2;
> LCB_F_RT = 1U << 3;
> LCB_F_PERCPU = 1U << 4;
> };

If you do this, then to use the __print_flags(), You'll also need to add:

TRACE_DEFINE_ENUM(LCB_F_SPIN);
TRACE_DEFINE_ENUM(LCB_F_READ);
TRACE_DEFINE_ENUM(LCB_F_WRITE);
TRACE_DEFINE_ENUM(LCB_F_RT);
TRACE_DEFINE_ENUM(LCB_F_PERCPU);

Which does slow down boot up slightly.

-- Steve