Hi Jeff,
On 8/21/25 1:16 PM, Jeff Layton wrote:
> We have a lot of old dprintk() call sites that aren't going anywhere
> anytime soon. At the same time, turning them up is a serious burden on
> the host due to the console locking overhead.
>
> Add a new Kconfig option that redirects dfprintk() output to the trace
> buffer. This is more efficient than logging to the console and allows
> for proper interleaving of dprintk and static tracepoint events.
>
> Since using trace_printk() causes scary warnings to pop at boot time,
> this new option defaults to "n".
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> include/linux/sunrpc/debug.h | 10 ++++++++--
> net/sunrpc/Kconfig | 14 ++++++++++++++
> 2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
> index 99a6fa4a1d6af0b275546a53957f07c9a509f2ac..fd9f79fa534ef001b3ec5e6d7e4b1099843b64a4 100644
> --- a/include/linux/sunrpc/debug.h
> +++ b/include/linux/sunrpc/debug.h
> @@ -30,17 +30,23 @@ extern unsigned int nlm_debug;
> #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
> # define ifdebug(fac) if (unlikely(rpc_debug & RPCDBG_##fac))
>
> +# if IS_ENABLED(CONFIG_SUNRPC_DEBUG_TRACE)
> +# define __sunrpc_printk(fmt, ...) trace_printk(fmt, ##__VA_ARGS__)
> +# else
> +# define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
This is the only reference I can find to "pr_default()" in my tree, and my compiler isn't
very happy about it. Am I missing a patch somewhere?
Thanks,
Anna
> +# endif
> +
> # define dfprintk(fac, fmt, ...) \
> do { \
> ifdebug(fac) \
> - printk(KERN_DEFAULT fmt, ##__VA_ARGS__); \
> + __sunrpc_printk(fmt, ##__VA_ARGS__); \
> } while (0)
>
> # define dfprintk_rcu(fac, fmt, ...) \
> do { \
> ifdebug(fac) { \
> rcu_read_lock(); \
> - printk(KERN_DEFAULT fmt, ##__VA_ARGS__); \
> + __sunrpc_printk(fmt, ##__VA_ARGS__); \
> rcu_read_unlock(); \
> } \
> } while (0)
> diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
> index 2d8b67dac7b5b58a8a86c3022dd573746fb22547..a570e7adf270fb8976f751266bbffe39ef696c6a 100644
> --- a/net/sunrpc/Kconfig
> +++ b/net/sunrpc/Kconfig
> @@ -101,6 +101,20 @@ config SUNRPC_DEBUG
>
> If unsure, say Y.
>
> +config SUNRPC_DEBUG_TRACE
> + bool "RPC: Send dfprintk() output to the trace buffer"
> + depends on SUNRPC_DEBUG && TRACING
> + default n
> + help
> + dprintk() output can be voluminous, which can overwhelm the
> + kernel's logging facility as it must be sent to the console.
> + This option causes dprintk() output to go to the trace buffer
> + instead of the kernel log.
> +
> + This will cause warnings about trace_printk() being used to be
> + logged at boot time, so say N unless you are debugging a problem
> + with sunrpc-based clients or services.
> +
> config SUNRPC_XPRT_RDMA
> tristate "RPC-over-RDMA transport"
> depends on SUNRPC && INFINIBAND && INFINIBAND_ADDR_TRANS
>
