From ec7d8e68ef0ec5c635c8f9e93cd881673445a397 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 22 Aug 2025 09:19:23 -0400 Subject: [PATCH] sunrpc: add a Kconfig option to redirect dfprintk() output to trace buffer 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 Reviewed-by: Chuck Lever Reviewed-by: Simon Horman Signed-off-by: Anna Schumaker --- 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 99a6fa4a1d6af..891f6173c951a 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, ...) printk(KERN_DEFAULT fmt, ##__VA_ARGS__) +# 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 2d8b67dac7b5b..a570e7adf270f 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 -- 2.47.3