Performance: Mark channel and buffer event disabled check unlikely

Channel and buffer are typically enabled when tracing, else the probes
would not be connected. Ensure the compiler optimizes for the right
usual case.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/lib/ringbuffer/frontend_api.h b/lib/ringbuffer/frontend_api.h
index b92ff290c300f07e90498612719fdfe190d9d79a..517af6350b7c620a881dddf13401b4979969a793 100644 (file)
--- a/lib/ringbuffer/frontend_api.h
+++ b/lib/ringbuffer/frontend_api.h
@@ -162,14 +162,14 @@ int lib_ring_buffer_reserve(const struct lib_ring_buffer_config *config,
        unsigned long o_begin, o_end, o_old;
        size_t before_hdr_pad = 0;
 
-       if (atomic_read(&chan->record_disabled))
+       if (unlikely(atomic_read(&chan->record_disabled)))
                return -EAGAIN;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
                buf = per_cpu_ptr(chan->backend.buf, ctx->cpu);
        else
                buf = chan->backend.buf;
-       if (atomic_read(&buf->record_disabled))
+       if (unlikely(atomic_read(&buf->record_disabled)))
                return -EAGAIN;
        ctx->buf = buf;