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@kernel.org>
---
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__)
+# 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
--
2.50.1Hi Jeff,
kernel test robot noticed the following build errors:
[auto build test ERROR on 80a1bea0cd81de70c56b37a8292c23d57419776f]
url: https://github.com/intel-lab-lkp/linux/commits/Jeff-Layton/sunrpc-remove-dfprintk_cont-and-dfprintk_rcu_cont/20250822-011902
base: 80a1bea0cd81de70c56b37a8292c23d57419776f
patch link: https://lore.kernel.org/r/20250821-nfs-testing-v1-2-f06099963eda%40kernel.org
patch subject: [PATCH 2/2] sunrpc: add a Kconfig option to redirect dfprintk() output to trace buffer
config: parisc-randconfig-001-20250822 (https://download.01.org/0day-ci/archive/20250822/202508221433.vcMr9C38-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 9.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250822/202508221433.vcMr9C38-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202508221433.vcMr9C38-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/proc.c:39:
fs/nfs/proc.c: In function 'nfs_proc_get_root':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/proc.c:66:2: note: in expansion of macro 'dprintk'
66 | dprintk("%s: call getattr\n", __func__);
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/nfs2xdr.c:21:
fs/nfs/nfs2xdr.c: In function 'decode_nfsdata':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/nfs2xdr.c:110:2: note: in expansion of macro 'dprintk'
110 | dprintk("NFS: server cheating in read result: "
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from fs/nfs/unlink.c:12:
fs/nfs/unlink.c: In function 'nfs_sillyrename':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
fs/nfs/unlink.c:453:2: note: in expansion of macro 'dfprintk'
453 | dfprintk(VFS, "NFS: silly-rename(%pd2, ct=%d)\n",
| ^~~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/nfs_fs.h:30,
from fs/nfs/direct.c:52:
fs/nfs/direct.c: In function 'nfs_file_direct_read':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
fs/nfs/direct.c:444:2: note: in expansion of macro 'dfprintk'
444 | dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
| ^~~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/auth.h:13,
from include/linux/nfs.h:12,
from fs/nfs/export.c:9:
fs/nfs/export.c: In function 'nfs_encode_fh':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/export.c:42:2: note: in expansion of macro 'dprintk'
42 | dprintk("%s: max fh len %d inode %p parent %p",
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/super.c:34:
fs/nfs/super.c: In function 'nfs_statfs':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/super.c:310:2: note: in expansion of macro 'dprintk'
310 | dprintk("%s: statfs error = %d\n", __func__, -error);
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/inode.c:27:
fs/nfs/inode.c: In function 'nfs_ilookup':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/inode.c:425:2: note: in expansion of macro 'dprintk'
425 | dprintk("%s: returning %p\n", __func__, inode);
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/mount_clnt.c:15:
fs/nfs/mount_clnt.c: In function 'nfs_mount':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/mount_clnt.c:168:2: note: in expansion of macro 'dprintk'
168 | dprintk("NFS: sending MNT request for %s:%s\n",
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/nfs_fs.h:30,
from fs/nfs/fs_context.c:18:
fs/nfs/fs_context.c: In function 'nfs_validate_transport_protocol':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/internal.h:175:5: note: in expansion of macro 'dprintk'
175 | ({ dprintk(fmt "\n", ## __VA_ARGS__); -EINVAL; }))
| ^~~~~~~
fs/nfs/fs_context.c:388:9: note: in expansion of macro 'nfs_invalf'
388 | return nfs_invalf(fc, "NFS: Unsupported transport protocol udp");
| ^~~~~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/nfs_fs.h:30,
from fs/nfs/file.c:26:
fs/nfs/file.c: In function 'nfs_file_open':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/file.c:66:2: note: in expansion of macro 'dprintk'
66 | dprintk("NFS: open file(%pD2)\n", filp);
| ^~~~~~~
cc1: some warnings being treated as errors
--
In file included from include/linux/sunrpc/types.h:16,
from include/linux/sunrpc/sched.h:15,
from include/linux/sunrpc/clnt.h:20,
from fs/nfs/write.c:19:
fs/nfs/write.c: In function 'nfs_update_folio':
>> include/linux/sunrpc/debug.h:36:37: error: implicit declaration of function 'pr_default'; did you mean 'pr_devel'? [-Werror=implicit-function-declaration]
36 | # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
| ^~~~~~~~~~
include/linux/sunrpc/debug.h:42:3: note: in expansion of macro '__sunrpc_printk'
42 | __sunrpc_printk(fmt, ##__VA_ARGS__); \
| ^~~~~~~~~~~~~~~
include/linux/sunrpc/debug.h:25:2: note: in expansion of macro 'dfprintk'
25 | dfprintk(FACILITY, fmt, ##__VA_ARGS__)
| ^~~~~~~~
fs/nfs/write.c:1348:2: note: in expansion of macro 'dprintk'
1348 | dprintk("NFS: nfs_update_folio(%pD2 %d@%lld)\n", file, count,
| ^~~~~~~
cc1: some warnings being treated as errors
..
vim +36 include/linux/sunrpc/debug.h
32
33 # if IS_ENABLED(CONFIG_SUNRPC_DEBUG_TRACE)
34 # define __sunrpc_printk(fmt, ...) trace_printk(fmt, ##__VA_ARGS__)
35 # else
> 36 # define __sunrpc_printk(fmt, ...) pr_default(fmt, ##__VA_ARGS__)
37 # endif
38
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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@kernel.org>
> ---
> 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
>
On Thu, 2025-08-21 at 15:44 -0400, Anna Schumaker wrote:
> 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@kernel.org>
> > ---
> > 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
>
No, my apologies. I had made a change in my test branch and didn't pick
it back into my send branch. That should be:
# define __sunrpc_printk(fmt, ...) printk(KERN_DEFAULT fmt, ##__VA_ARGS__)
I can resend if you are amenable to this patch.
> > +# 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
> >
--
Jeff Layton <jlayton@kernel.org>
On 8/21/25 3:51 PM, Jeff Layton wrote:
> On Thu, 2025-08-21 at 15:44 -0400, Anna Schumaker wrote:
>> 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@kernel.org>
>>> ---
>>> 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
>>
>
> No, my apologies. I had made a change in my test branch and didn't pick
> it back into my send branch. That should be:
>
> # define __sunrpc_printk(fmt, ...) printk(KERN_DEFAULT fmt, ##__VA_ARGS__)
>
> I can resend if you are amenable to this patch.
Yes, please do resend!
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
>>>
>
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