* [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
@ 2020-04-20 18:43 Orson Zhai
2020-04-20 19:10 ` Leon Romanovsky
0 siblings, 1 reply; 8+ messages in thread
From: Orson Zhai @ 2020-04-20 18:43 UTC (permalink / raw)
To: Jason Baron, Randy Dunlap, linux-kernel, linux-doc, netdev, linux-rdma
Cc: Jonathan Corbet, Petr Mladek, Sergey Senozhatsky, Steven Rostedt,
Greg Kroah-Hartman, David S . Miller, Jakub Kicinski,
Doug Ledford, Jason Gunthorpe, Andrew Morton, orsonzhai,
kernel-team, Orson Zhai
From: Orson Zhai <orson.zhai@unisoc.com>
Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
debug will be tied to them.
This is useful for people who only want to enable dynamic debug for
kernel modules without worrying about kernel image size and memory
consumption is increasing too much.
Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Changes to V2:
1) Change DEBUG_MODULE to DYNAMIC_DEBUG_MODULE.
2) Change more #if defined(DYNAMIC_DEBUG) condition (in net.h, netdevice.h
and ib_verbs.h).
3) Rewrite description in howto document.
4) Add acked-by from Greg.
Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++
include/linux/dev_printk.h | 6 ++++--
include/linux/dynamic_debug.h | 2 +-
include/linux/net.h | 3 ++-
include/linux/netdevice.h | 6 ++++--
include/linux/printk.h | 14 +++++++++-----
include/rdma/ib_verbs.h | 6 ++++--
lib/Kconfig.debug | 12 ++++++++++++
lib/Makefile | 2 +-
lib/dynamic_debug.c | 9 +++++++--
10 files changed, 49 insertions(+), 16 deletions(-)
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 0dc2eb8..1012bd9 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if
``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
enabled per-callsite.
+If you do not want to enable dynamic debug globally (i.e. in some embedded
+system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
+debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
+modules which you'd like to dynamically debug later.
+
If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
shortcut for ``print_hex_dump(KERN_DEBUG)``.
diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
index 5aad06b..3028b64 100644
--- a/include/linux/dev_printk.h
+++ b/include/linux/dev_printk.h
@@ -109,7 +109,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...)
#define dev_info(dev, fmt, ...) \
_dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define dev_dbg(dev, fmt, ...) \
dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
#elif defined(DEBUG)
@@ -181,7 +182,8 @@ do { \
dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
#define dev_info_ratelimited(dev, fmt, ...) \
dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
/* descriptor check is first to prevent flooding with "callbacks suppressed" */
#define dev_dbg_ratelimited(dev, fmt, ...) \
do { \
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 4cf02ec..abcd5fd 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -48,7 +48,7 @@ struct _ddebug {
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *modname);
extern int ddebug_remove_module(const char *mod_name);
diff --git a/include/linux/net.h b/include/linux/net.h
index 6451425..7b7b21a 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -264,7 +264,8 @@ do { \
net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
#define net_info_ratelimited(fmt, ...) \
net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define net_dbg_ratelimited(fmt, ...) \
do { \
DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 130a668..e874643 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4868,7 +4868,8 @@ do { \
#define MODULE_ALIAS_NETDEV(device) \
MODULE_ALIAS("netdev-" device)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define netdev_dbg(__dev, format, args...) \
do { \
dynamic_netdev_dbg(__dev, format, ##args); \
@@ -4938,7 +4939,8 @@ do { \
#define netif_info(priv, type, dev, fmt, args...) \
netif_level(info, priv, type, dev, fmt, ##args)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define netif_dbg(priv, type, netdev, format, args...) \
do { \
if (netif_msg_##type(priv)) \
diff --git a/include/linux/printk.h b/include/linux/printk.h
index e061635..b64c39c 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -286,8 +286,9 @@ extern int kptr_restrict;
/*
* These can be used to print at the various log levels.
* All of these will print unconditionally, although note that pr_debug()
- * and other debug macros are compiled out unless either DEBUG is defined
- * or CONFIG_DYNAMIC_DEBUG is set.
+ * and other debug macros are compiled out unless either DEBUG is defined,
+ * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
+ * DYNAMIC_DEBUG_MODULE being defined for any modules.
*/
#define pr_emerg(fmt, ...) \
printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
@@ -322,7 +323,8 @@ extern int kptr_restrict;
/* If you are writing a driver, please use dev_dbg instead */
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#include <linux/dynamic_debug.h>
/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
@@ -448,7 +450,8 @@ extern int kptr_restrict;
#endif
/* If you are writing a driver, please use dev_dbg instead */
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
/* descriptor check is first to prevent flooding with "callbacks suppressed" */
#define pr_debug_ratelimited(fmt, ...) \
do { \
@@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
#endif
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
groupsize, buf, len, ascii) \
dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index bbc5cfb..e072ef6 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -100,7 +100,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...);
__printf(2, 3) __cold
void ibdev_info(const struct ib_device *ibdev, const char *format, ...);
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define ibdev_dbg(__dev, format, args...) \
dynamic_ibdev_dbg(__dev, format, ##args)
#else
@@ -133,7 +134,8 @@ do { \
#define ibdev_info_ratelimited(ibdev, fmt, ...) \
ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
/* descriptor check is first to prevent flooding with "callbacks suppressed" */
#define ibdev_dbg_ratelimited(ibdev, fmt, ...) \
do { \
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 21d9c5f..9ab791b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
default n
depends on PRINTK
depends on (DEBUG_FS || PROC_FS)
+ select DYNAMIC_DEBUG_CORE
help
Compiles debug level messages into the kernel, which would not
@@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
See Documentation/admin-guide/dynamic-debug-howto.rst for additional
information.
+config DYNAMIC_DEBUG_CORE
+ bool "Enable core function of dynamic debug support"
+ depends on PRINTK
+ depends on (DEBUG_FS || PROC_FS)
+ help
+ Enable core functional support of dynamic debug. It is useful
+ when you want to tie dynamic debug to your kernel modules with
+ DYNAMIC_DEBUG_MODULE defined for each of them, especially for
+ the case of embedded system where the kernel image size is
+ sensitive for people.
+
config SYMBOLIC_ERRNAME
bool "Support symbolic error names in printf"
default y if PRINTK
diff --git a/lib/Makefile b/lib/Makefile
index 685aee6..8952772 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
-obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
+obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
obj-$(CONFIG_NLATTR) += nlattr.o
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8f199f4..321437b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
int verbose_bytes = 0;
if (&__start___verbose == &__stop___verbose) {
- pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
- return 1;
+ if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
+ pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
+ return 1;
+ }
+ pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
+ ddebug_init_success = 1;
+ return 0;
}
iter = __start___verbose;
modname = iter->modname;
--
2.7.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-04-20 18:43 [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only Orson Zhai
@ 2020-04-20 19:10 ` Leon Romanovsky
2020-04-22 13:06 ` Orson Zhai
0 siblings, 1 reply; 8+ messages in thread
From: Leon Romanovsky @ 2020-04-20 19:10 UTC (permalink / raw)
To: Orson Zhai
Cc: Jason Baron, Randy Dunlap, linux-kernel, linux-doc, netdev,
linux-rdma, Jonathan Corbet, Petr Mladek, Sergey Senozhatsky,
Steven Rostedt, Greg Kroah-Hartman, David S . Miller,
Jakub Kicinski, Doug Ledford, Jason Gunthorpe, Andrew Morton,
orsonzhai, kernel-team, Orson Zhai
On Tue, Apr 21, 2020 at 02:43:48AM +0800, Orson Zhai wrote:
> From: Orson Zhai <orson.zhai@unisoc.com>
>
> Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
> CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
> debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
> debug will be tied to them.
>
> This is useful for people who only want to enable dynamic debug for
> kernel modules without worrying about kernel image size and memory
> consumption is increasing too much.
Let's talk about extreme case, what is the output of bloat-o-meter
for allyesconfig build with and without dynamic debug?
I imagine that people who are interested in decreasing memory
footprint will use minimal config anyway, so it is very interesting
to see who is the target audience for this change?
Thanks
>
> Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> Changes to V2:
> 1) Change DEBUG_MODULE to DYNAMIC_DEBUG_MODULE.
> 2) Change more #if defined(DYNAMIC_DEBUG) condition (in net.h, netdevice.h
> and ib_verbs.h).
> 3) Rewrite description in howto document.
> 4) Add acked-by from Greg.
>
>
> Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++
> include/linux/dev_printk.h | 6 ++++--
> include/linux/dynamic_debug.h | 2 +-
> include/linux/net.h | 3 ++-
> include/linux/netdevice.h | 6 ++++--
> include/linux/printk.h | 14 +++++++++-----
> include/rdma/ib_verbs.h | 6 ++++--
> lib/Kconfig.debug | 12 ++++++++++++
> lib/Makefile | 2 +-
> lib/dynamic_debug.c | 9 +++++++--
> 10 files changed, 49 insertions(+), 16 deletions(-)
>
> diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
> index 0dc2eb8..1012bd9 100644
> --- a/Documentation/admin-guide/dynamic-debug-howto.rst
> +++ b/Documentation/admin-guide/dynamic-debug-howto.rst
> @@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if
> ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
> enabled per-callsite.
>
> +If you do not want to enable dynamic debug globally (i.e. in some embedded
> +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
> +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
> +modules which you'd like to dynamically debug later.
> +
> If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
> shortcut for ``print_hex_dump(KERN_DEBUG)``.
>
> diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
> index 5aad06b..3028b64 100644
> --- a/include/linux/dev_printk.h
> +++ b/include/linux/dev_printk.h
> @@ -109,7 +109,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...)
> #define dev_info(dev, fmt, ...) \
> _dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define dev_dbg(dev, fmt, ...) \
> dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
> #elif defined(DEBUG)
> @@ -181,7 +182,8 @@ do { \
> dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
> #define dev_info_ratelimited(dev, fmt, ...) \
> dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> #define dev_dbg_ratelimited(dev, fmt, ...) \
> do { \
> diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> index 4cf02ec..abcd5fd 100644
> --- a/include/linux/dynamic_debug.h
> +++ b/include/linux/dynamic_debug.h
> @@ -48,7 +48,7 @@ struct _ddebug {
>
>
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
> int ddebug_add_module(struct _ddebug *tab, unsigned int n,
> const char *modname);
> extern int ddebug_remove_module(const char *mod_name);
> diff --git a/include/linux/net.h b/include/linux/net.h
> index 6451425..7b7b21a 100644
> --- a/include/linux/net.h
> +++ b/include/linux/net.h
> @@ -264,7 +264,8 @@ do { \
> net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
> #define net_info_ratelimited(fmt, ...) \
> net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define net_dbg_ratelimited(fmt, ...) \
> do { \
> DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 130a668..e874643 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -4868,7 +4868,8 @@ do { \
> #define MODULE_ALIAS_NETDEV(device) \
> MODULE_ALIAS("netdev-" device)
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define netdev_dbg(__dev, format, args...) \
> do { \
> dynamic_netdev_dbg(__dev, format, ##args); \
> @@ -4938,7 +4939,8 @@ do { \
> #define netif_info(priv, type, dev, fmt, args...) \
> netif_level(info, priv, type, dev, fmt, ##args)
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define netif_dbg(priv, type, netdev, format, args...) \
> do { \
> if (netif_msg_##type(priv)) \
> diff --git a/include/linux/printk.h b/include/linux/printk.h
> index e061635..b64c39c 100644
> --- a/include/linux/printk.h
> +++ b/include/linux/printk.h
> @@ -286,8 +286,9 @@ extern int kptr_restrict;
> /*
> * These can be used to print at the various log levels.
> * All of these will print unconditionally, although note that pr_debug()
> - * and other debug macros are compiled out unless either DEBUG is defined
> - * or CONFIG_DYNAMIC_DEBUG is set.
> + * and other debug macros are compiled out unless either DEBUG is defined,
> + * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
> + * DYNAMIC_DEBUG_MODULE being defined for any modules.
> */
> #define pr_emerg(fmt, ...) \
> printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
> @@ -322,7 +323,8 @@ extern int kptr_restrict;
>
>
> /* If you are writing a driver, please use dev_dbg instead */
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #include <linux/dynamic_debug.h>
>
> /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
> @@ -448,7 +450,8 @@ extern int kptr_restrict;
> #endif
>
> /* If you are writing a driver, please use dev_dbg instead */
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> #define pr_debug_ratelimited(fmt, ...) \
> do { \
> @@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
>
> #endif
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
> groupsize, buf, len, ascii) \
> dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index bbc5cfb..e072ef6 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -100,7 +100,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...);
> __printf(2, 3) __cold
> void ibdev_info(const struct ib_device *ibdev, const char *format, ...);
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> #define ibdev_dbg(__dev, format, args...) \
> dynamic_ibdev_dbg(__dev, format, ##args)
> #else
> @@ -133,7 +134,8 @@ do { \
> #define ibdev_info_ratelimited(ibdev, fmt, ...) \
> ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__)
>
> -#if defined(CONFIG_DYNAMIC_DEBUG)
> +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> #define ibdev_dbg_ratelimited(ibdev, fmt, ...) \
> do { \
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 21d9c5f..9ab791b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
> default n
> depends on PRINTK
> depends on (DEBUG_FS || PROC_FS)
> + select DYNAMIC_DEBUG_CORE
> help
>
> Compiles debug level messages into the kernel, which would not
> @@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
> See Documentation/admin-guide/dynamic-debug-howto.rst for additional
> information.
>
> +config DYNAMIC_DEBUG_CORE
> + bool "Enable core function of dynamic debug support"
> + depends on PRINTK
> + depends on (DEBUG_FS || PROC_FS)
> + help
> + Enable core functional support of dynamic debug. It is useful
> + when you want to tie dynamic debug to your kernel modules with
> + DYNAMIC_DEBUG_MODULE defined for each of them, especially for
> + the case of embedded system where the kernel image size is
> + sensitive for people.
> +
> config SYMBOLIC_ERRNAME
> bool "Support symbolic error names in printf"
> default y if PRINTK
> diff --git a/lib/Makefile b/lib/Makefile
> index 685aee6..8952772 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
>
> obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
>
> -obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
> +obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
> obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
>
> obj-$(CONFIG_NLATTR) += nlattr.o
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index 8f199f4..321437b 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
> int verbose_bytes = 0;
>
> if (&__start___verbose == &__stop___verbose) {
> - pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> - return 1;
> + if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
> + pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> + return 1;
> + }
> + pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
> + ddebug_init_success = 1;
> + return 0;
> }
> iter = __start___verbose;
> modname = iter->modname;
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-04-20 19:10 ` Leon Romanovsky
@ 2020-04-22 13:06 ` Orson Zhai
2020-04-22 14:25 ` Leon Romanovsky
0 siblings, 1 reply; 8+ messages in thread
From: Orson Zhai @ 2020-04-22 13:06 UTC (permalink / raw)
To: Leon Romanovsky
Cc: Orson Zhai, Jason Baron, Randy Dunlap, Linux Kernel Mailing List,
linux-doc, netdev, linux-rdma, Jonathan Corbet, Petr Mladek,
Sergey Senozhatsky, Steven Rostedt, Greg Kroah-Hartman,
David S . Miller, Jakub Kicinski, Doug Ledford, Jason Gunthorpe,
Andrew Morton, Android Kernel Team, Orson Zhai
On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
>
> On Tue, Apr 21, 2020 at 02:43:48AM +0800, Orson Zhai wrote:
> > From: Orson Zhai <orson.zhai@unisoc.com>
> >
> > Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
> > CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
> > debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
> > debug will be tied to them.
> >
> > This is useful for people who only want to enable dynamic debug for
> > kernel modules without worrying about kernel image size and memory
> > consumption is increasing too much.
>
> Let's talk about extreme case, what is the output of bloat-o-meter
> for allyesconfig build with and without dynamic debug?
It is a good question.
I have done exactly what you ask for x86 build yesterday. Here is the result:
Total: Before=306735842, After=312600260, chg +1.91%
In my case of a mobile phone, the difference is about 2MiB on 14MiB kernel image
(not compressed).
The reduced size is often critical sometimes, especially for low-end phones, say
a system with 512MB DDR memory.
Another smaller arm system in my hand, kernel size reduced about
600KiB to the zImage
of 4.2MiB.
>
> I imagine that people who are interested in decreasing memory
> footprint will use minimal config anyway, so it is very interesting
> to see who is the target audience for this change?
My motivation came from the concept of GKI (Generic Kernel Image) in Android.
Google will release a common kernel image (binary) to all of the Android system
vendors in the world instead of letting them to build their owns as before.
Every SoC vendor's device drivers will be provided in kernel modules only.
By my patch, the driver owners could debug their modules in field (say
production releases)
without having to enable dynamic debug for the whole GKI.
-Orson
>
> Thanks
>
> >
> > Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> > Changes to V2:
> > 1) Change DEBUG_MODULE to DYNAMIC_DEBUG_MODULE.
> > 2) Change more #if defined(DYNAMIC_DEBUG) condition (in net.h, netdevice.h
> > and ib_verbs.h).
> > 3) Rewrite description in howto document.
> > 4) Add acked-by from Greg.
> >
> >
> > Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++
> > include/linux/dev_printk.h | 6 ++++--
> > include/linux/dynamic_debug.h | 2 +-
> > include/linux/net.h | 3 ++-
> > include/linux/netdevice.h | 6 ++++--
> > include/linux/printk.h | 14 +++++++++-----
> > include/rdma/ib_verbs.h | 6 ++++--
> > lib/Kconfig.debug | 12 ++++++++++++
> > lib/Makefile | 2 +-
> > lib/dynamic_debug.c | 9 +++++++--
> > 10 files changed, 49 insertions(+), 16 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
> > index 0dc2eb8..1012bd9 100644
> > --- a/Documentation/admin-guide/dynamic-debug-howto.rst
> > +++ b/Documentation/admin-guide/dynamic-debug-howto.rst
> > @@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if
> > ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
> > enabled per-callsite.
> >
> > +If you do not want to enable dynamic debug globally (i.e. in some embedded
> > +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
> > +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
> > +modules which you'd like to dynamically debug later.
> > +
> > If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
> > shortcut for ``print_hex_dump(KERN_DEBUG)``.
> >
> > diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
> > index 5aad06b..3028b64 100644
> > --- a/include/linux/dev_printk.h
> > +++ b/include/linux/dev_printk.h
> > @@ -109,7 +109,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...)
> > #define dev_info(dev, fmt, ...) \
> > _dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define dev_dbg(dev, fmt, ...) \
> > dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
> > #elif defined(DEBUG)
> > @@ -181,7 +182,8 @@ do { \
> > dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
> > #define dev_info_ratelimited(dev, fmt, ...) \
> > dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > #define dev_dbg_ratelimited(dev, fmt, ...) \
> > do { \
> > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> > index 4cf02ec..abcd5fd 100644
> > --- a/include/linux/dynamic_debug.h
> > +++ b/include/linux/dynamic_debug.h
> > @@ -48,7 +48,7 @@ struct _ddebug {
> >
> >
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
> > int ddebug_add_module(struct _ddebug *tab, unsigned int n,
> > const char *modname);
> > extern int ddebug_remove_module(const char *mod_name);
> > diff --git a/include/linux/net.h b/include/linux/net.h
> > index 6451425..7b7b21a 100644
> > --- a/include/linux/net.h
> > +++ b/include/linux/net.h
> > @@ -264,7 +264,8 @@ do { \
> > net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
> > #define net_info_ratelimited(fmt, ...) \
> > net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define net_dbg_ratelimited(fmt, ...) \
> > do { \
> > DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > index 130a668..e874643 100644
> > --- a/include/linux/netdevice.h
> > +++ b/include/linux/netdevice.h
> > @@ -4868,7 +4868,8 @@ do { \
> > #define MODULE_ALIAS_NETDEV(device) \
> > MODULE_ALIAS("netdev-" device)
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define netdev_dbg(__dev, format, args...) \
> > do { \
> > dynamic_netdev_dbg(__dev, format, ##args); \
> > @@ -4938,7 +4939,8 @@ do { \
> > #define netif_info(priv, type, dev, fmt, args...) \
> > netif_level(info, priv, type, dev, fmt, ##args)
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define netif_dbg(priv, type, netdev, format, args...) \
> > do { \
> > if (netif_msg_##type(priv)) \
> > diff --git a/include/linux/printk.h b/include/linux/printk.h
> > index e061635..b64c39c 100644
> > --- a/include/linux/printk.h
> > +++ b/include/linux/printk.h
> > @@ -286,8 +286,9 @@ extern int kptr_restrict;
> > /*
> > * These can be used to print at the various log levels.
> > * All of these will print unconditionally, although note that pr_debug()
> > - * and other debug macros are compiled out unless either DEBUG is defined
> > - * or CONFIG_DYNAMIC_DEBUG is set.
> > + * and other debug macros are compiled out unless either DEBUG is defined,
> > + * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
> > + * DYNAMIC_DEBUG_MODULE being defined for any modules.
> > */
> > #define pr_emerg(fmt, ...) \
> > printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
> > @@ -322,7 +323,8 @@ extern int kptr_restrict;
> >
> >
> > /* If you are writing a driver, please use dev_dbg instead */
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #include <linux/dynamic_debug.h>
> >
> > /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
> > @@ -448,7 +450,8 @@ extern int kptr_restrict;
> > #endif
> >
> > /* If you are writing a driver, please use dev_dbg instead */
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > #define pr_debug_ratelimited(fmt, ...) \
> > do { \
> > @@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
> >
> > #endif
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
> > groupsize, buf, len, ascii) \
> > dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
> > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> > index bbc5cfb..e072ef6 100644
> > --- a/include/rdma/ib_verbs.h
> > +++ b/include/rdma/ib_verbs.h
> > @@ -100,7 +100,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...);
> > __printf(2, 3) __cold
> > void ibdev_info(const struct ib_device *ibdev, const char *format, ...);
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > #define ibdev_dbg(__dev, format, args...) \
> > dynamic_ibdev_dbg(__dev, format, ##args)
> > #else
> > @@ -133,7 +134,8 @@ do { \
> > #define ibdev_info_ratelimited(ibdev, fmt, ...) \
> > ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__)
> >
> > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > #define ibdev_dbg_ratelimited(ibdev, fmt, ...) \
> > do { \
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index 21d9c5f..9ab791b 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
> > default n
> > depends on PRINTK
> > depends on (DEBUG_FS || PROC_FS)
> > + select DYNAMIC_DEBUG_CORE
> > help
> >
> > Compiles debug level messages into the kernel, which would not
> > @@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
> > See Documentation/admin-guide/dynamic-debug-howto.rst for additional
> > information.
> >
> > +config DYNAMIC_DEBUG_CORE
> > + bool "Enable core function of dynamic debug support"
> > + depends on PRINTK
> > + depends on (DEBUG_FS || PROC_FS)
> > + help
> > + Enable core functional support of dynamic debug. It is useful
> > + when you want to tie dynamic debug to your kernel modules with
> > + DYNAMIC_DEBUG_MODULE defined for each of them, especially for
> > + the case of embedded system where the kernel image size is
> > + sensitive for people.
> > +
> > config SYMBOLIC_ERRNAME
> > bool "Support symbolic error names in printf"
> > default y if PRINTK
> > diff --git a/lib/Makefile b/lib/Makefile
> > index 685aee6..8952772 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
> >
> > obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
> >
> > -obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
> > +obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
> > obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
> >
> > obj-$(CONFIG_NLATTR) += nlattr.o
> > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> > index 8f199f4..321437b 100644
> > --- a/lib/dynamic_debug.c
> > +++ b/lib/dynamic_debug.c
> > @@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
> > int verbose_bytes = 0;
> >
> > if (&__start___verbose == &__stop___verbose) {
> > - pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > - return 1;
> > + if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
> > + pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > + return 1;
> > + }
> > + pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
> > + ddebug_init_success = 1;
> > + return 0;
> > }
> > iter = __start___verbose;
> > modname = iter->modname;
> > --
> > 2.7.4
> >
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-04-22 13:06 ` Orson Zhai
@ 2020-04-22 14:25 ` Leon Romanovsky
2020-04-22 16:02 ` Orson Zhai
0 siblings, 1 reply; 8+ messages in thread
From: Leon Romanovsky @ 2020-04-22 14:25 UTC (permalink / raw)
To: Orson Zhai
Cc: Orson Zhai, Jason Baron, Randy Dunlap, Linux Kernel Mailing List,
linux-doc, netdev, linux-rdma, Jonathan Corbet, Petr Mladek,
Sergey Senozhatsky, Steven Rostedt, Greg Kroah-Hartman,
David S . Miller, Jakub Kicinski, Doug Ledford, Jason Gunthorpe,
Andrew Morton, Android Kernel Team, Orson Zhai
On Wed, Apr 22, 2020 at 09:06:08PM +0800, Orson Zhai wrote:
> On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
> >
> > On Tue, Apr 21, 2020 at 02:43:48AM +0800, Orson Zhai wrote:
> > > From: Orson Zhai <orson.zhai@unisoc.com>
> > >
> > > Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
> > > CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
> > > debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
> > > debug will be tied to them.
> > >
> > > This is useful for people who only want to enable dynamic debug for
> > > kernel modules without worrying about kernel image size and memory
> > > consumption is increasing too much.
> >
> > Let's talk about extreme case, what is the output of bloat-o-meter
> > for allyesconfig build with and without dynamic debug?
>
> It is a good question.
> I have done exactly what you ask for x86 build yesterday. Here is the result:
> Total: Before=306735842, After=312600260, chg +1.91%
>
> In my case of a mobile phone, the difference is about 2MiB on 14MiB kernel image
> (not compressed).
> The reduced size is often critical sometimes, especially for low-end phones, say
> a system with 512MB DDR memory.
>
> Another smaller arm system in my hand, kernel size reduced about
> 600KiB to the zImage
> of 4.2MiB.
The numbers support the assumption that "memory consumption is increasing
too much" sentence is not fully accurate. According to the result of
compilation for mobile phone, it looks like the problem with explode of
prints, which is better to clean, before introducing extra config.
>
> >
> > I imagine that people who are interested in decreasing memory
> > footprint will use minimal config anyway, so it is very interesting
> > to see who is the target audience for this change?
>
> My motivation came from the concept of GKI (Generic Kernel Image) in Android.
> Google will release a common kernel image (binary) to all of the Android system
> vendors in the world instead of letting them to build their owns as before.
> Every SoC vendor's device drivers will be provided in kernel modules only.
> By my patch, the driver owners could debug their modules in field (say
> production releases)
> without having to enable dynamic debug for the whole GKI.
Will Google release that binary with CONFIG_DYNAMIC_DEBUG_CORE disabled?
If yes, by introducing you kernel config, these driver authors won't
be able to enable debug on GKI (at least for production) at all.
If no, what is the point of this change?
>
> -Orson
>
> >
> > Thanks
> >
> > >
> > > Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
> > > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > ---
> > > Changes to V2:
> > > 1) Change DEBUG_MODULE to DYNAMIC_DEBUG_MODULE.
> > > 2) Change more #if defined(DYNAMIC_DEBUG) condition (in net.h, netdevice.h
> > > and ib_verbs.h).
> > > 3) Rewrite description in howto document.
> > > 4) Add acked-by from Greg.
> > >
> > >
> > > Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++
> > > include/linux/dev_printk.h | 6 ++++--
> > > include/linux/dynamic_debug.h | 2 +-
> > > include/linux/net.h | 3 ++-
> > > include/linux/netdevice.h | 6 ++++--
> > > include/linux/printk.h | 14 +++++++++-----
> > > include/rdma/ib_verbs.h | 6 ++++--
> > > lib/Kconfig.debug | 12 ++++++++++++
> > > lib/Makefile | 2 +-
> > > lib/dynamic_debug.c | 9 +++++++--
> > > 10 files changed, 49 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
> > > index 0dc2eb8..1012bd9 100644
> > > --- a/Documentation/admin-guide/dynamic-debug-howto.rst
> > > +++ b/Documentation/admin-guide/dynamic-debug-howto.rst
> > > @@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if
> > > ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
> > > enabled per-callsite.
> > >
> > > +If you do not want to enable dynamic debug globally (i.e. in some embedded
> > > +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
> > > +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
> > > +modules which you'd like to dynamically debug later.
> > > +
> > > If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
> > > shortcut for ``print_hex_dump(KERN_DEBUG)``.
> > >
> > > diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
> > > index 5aad06b..3028b64 100644
> > > --- a/include/linux/dev_printk.h
> > > +++ b/include/linux/dev_printk.h
> > > @@ -109,7 +109,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...)
> > > #define dev_info(dev, fmt, ...) \
> > > _dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define dev_dbg(dev, fmt, ...) \
> > > dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
> > > #elif defined(DEBUG)
> > > @@ -181,7 +182,8 @@ do { \
> > > dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
> > > #define dev_info_ratelimited(dev, fmt, ...) \
> > > dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > #define dev_dbg_ratelimited(dev, fmt, ...) \
> > > do { \
> > > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> > > index 4cf02ec..abcd5fd 100644
> > > --- a/include/linux/dynamic_debug.h
> > > +++ b/include/linux/dynamic_debug.h
> > > @@ -48,7 +48,7 @@ struct _ddebug {
> > >
> > >
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
> > > int ddebug_add_module(struct _ddebug *tab, unsigned int n,
> > > const char *modname);
> > > extern int ddebug_remove_module(const char *mod_name);
> > > diff --git a/include/linux/net.h b/include/linux/net.h
> > > index 6451425..7b7b21a 100644
> > > --- a/include/linux/net.h
> > > +++ b/include/linux/net.h
> > > @@ -264,7 +264,8 @@ do { \
> > > net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
> > > #define net_info_ratelimited(fmt, ...) \
> > > net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define net_dbg_ratelimited(fmt, ...) \
> > > do { \
> > > DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
> > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > > index 130a668..e874643 100644
> > > --- a/include/linux/netdevice.h
> > > +++ b/include/linux/netdevice.h
> > > @@ -4868,7 +4868,8 @@ do { \
> > > #define MODULE_ALIAS_NETDEV(device) \
> > > MODULE_ALIAS("netdev-" device)
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define netdev_dbg(__dev, format, args...) \
> > > do { \
> > > dynamic_netdev_dbg(__dev, format, ##args); \
> > > @@ -4938,7 +4939,8 @@ do { \
> > > #define netif_info(priv, type, dev, fmt, args...) \
> > > netif_level(info, priv, type, dev, fmt, ##args)
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define netif_dbg(priv, type, netdev, format, args...) \
> > > do { \
> > > if (netif_msg_##type(priv)) \
> > > diff --git a/include/linux/printk.h b/include/linux/printk.h
> > > index e061635..b64c39c 100644
> > > --- a/include/linux/printk.h
> > > +++ b/include/linux/printk.h
> > > @@ -286,8 +286,9 @@ extern int kptr_restrict;
> > > /*
> > > * These can be used to print at the various log levels.
> > > * All of these will print unconditionally, although note that pr_debug()
> > > - * and other debug macros are compiled out unless either DEBUG is defined
> > > - * or CONFIG_DYNAMIC_DEBUG is set.
> > > + * and other debug macros are compiled out unless either DEBUG is defined,
> > > + * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
> > > + * DYNAMIC_DEBUG_MODULE being defined for any modules.
> > > */
> > > #define pr_emerg(fmt, ...) \
> > > printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
> > > @@ -322,7 +323,8 @@ extern int kptr_restrict;
> > >
> > >
> > > /* If you are writing a driver, please use dev_dbg instead */
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #include <linux/dynamic_debug.h>
> > >
> > > /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
> > > @@ -448,7 +450,8 @@ extern int kptr_restrict;
> > > #endif
> > >
> > > /* If you are writing a driver, please use dev_dbg instead */
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > #define pr_debug_ratelimited(fmt, ...) \
> > > do { \
> > > @@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
> > >
> > > #endif
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
> > > groupsize, buf, len, ascii) \
> > > dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
> > > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> > > index bbc5cfb..e072ef6 100644
> > > --- a/include/rdma/ib_verbs.h
> > > +++ b/include/rdma/ib_verbs.h
> > > @@ -100,7 +100,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...);
> > > __printf(2, 3) __cold
> > > void ibdev_info(const struct ib_device *ibdev, const char *format, ...);
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > #define ibdev_dbg(__dev, format, args...) \
> > > dynamic_ibdev_dbg(__dev, format, ##args)
> > > #else
> > > @@ -133,7 +134,8 @@ do { \
> > > #define ibdev_info_ratelimited(ibdev, fmt, ...) \
> > > ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__)
> > >
> > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > #define ibdev_dbg_ratelimited(ibdev, fmt, ...) \
> > > do { \
> > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > > index 21d9c5f..9ab791b 100644
> > > --- a/lib/Kconfig.debug
> > > +++ b/lib/Kconfig.debug
> > > @@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
> > > default n
> > > depends on PRINTK
> > > depends on (DEBUG_FS || PROC_FS)
> > > + select DYNAMIC_DEBUG_CORE
> > > help
> > >
> > > Compiles debug level messages into the kernel, which would not
> > > @@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
> > > See Documentation/admin-guide/dynamic-debug-howto.rst for additional
> > > information.
> > >
> > > +config DYNAMIC_DEBUG_CORE
> > > + bool "Enable core function of dynamic debug support"
> > > + depends on PRINTK
> > > + depends on (DEBUG_FS || PROC_FS)
> > > + help
> > > + Enable core functional support of dynamic debug. It is useful
> > > + when you want to tie dynamic debug to your kernel modules with
> > > + DYNAMIC_DEBUG_MODULE defined for each of them, especially for
> > > + the case of embedded system where the kernel image size is
> > > + sensitive for people.
> > > +
> > > config SYMBOLIC_ERRNAME
> > > bool "Support symbolic error names in printf"
> > > default y if PRINTK
> > > diff --git a/lib/Makefile b/lib/Makefile
> > > index 685aee6..8952772 100644
> > > --- a/lib/Makefile
> > > +++ b/lib/Makefile
> > > @@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
> > >
> > > obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
> > >
> > > -obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
> > > +obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
> > > obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
> > >
> > > obj-$(CONFIG_NLATTR) += nlattr.o
> > > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> > > index 8f199f4..321437b 100644
> > > --- a/lib/dynamic_debug.c
> > > +++ b/lib/dynamic_debug.c
> > > @@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
> > > int verbose_bytes = 0;
> > >
> > > if (&__start___verbose == &__stop___verbose) {
> > > - pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > > - return 1;
> > > + if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
> > > + pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > > + return 1;
> > > + }
> > > + pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
> > > + ddebug_init_success = 1;
> > > + return 0;
> > > }
> > > iter = __start___verbose;
> > > modname = iter->modname;
> > > --
> > > 2.7.4
> > >
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-04-22 14:25 ` Leon Romanovsky
@ 2020-04-22 16:02 ` Orson Zhai
2020-05-15 9:55 ` Petr Mladek
0 siblings, 1 reply; 8+ messages in thread
From: Orson Zhai @ 2020-04-22 16:02 UTC (permalink / raw)
To: Leon Romanovsky
Cc: Orson Zhai, Jason Baron, Randy Dunlap, Linux Kernel Mailing List,
linux-doc, netdev, linux-rdma, Jonathan Corbet, Petr Mladek,
Sergey Senozhatsky, Steven Rostedt, Greg Kroah-Hartman,
David S . Miller, Jakub Kicinski, Doug Ledford, Jason Gunthorpe,
Andrew Morton, Android Kernel Team, Orson Zhai
On Wed, Apr 22, 2020 at 10:25 PM Leon Romanovsky <leon@kernel.org> wrote:
>
> On Wed, Apr 22, 2020 at 09:06:08PM +0800, Orson Zhai wrote:
> > On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
> > >
> > > On Tue, Apr 21, 2020 at 02:43:48AM +0800, Orson Zhai wrote:
> > > > From: Orson Zhai <orson.zhai@unisoc.com>
> > > >
> > > > Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
> > > > CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
> > > > debug. With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
> > > > debug will be tied to them.
> > > >
> > > > This is useful for people who only want to enable dynamic debug for
> > > > kernel modules without worrying about kernel image size and memory
> > > > consumption is increasing too much.
> > >
> > > Let's talk about extreme case, what is the output of bloat-o-meter
> > > for allyesconfig build with and without dynamic debug?
> >
> > It is a good question.
> > I have done exactly what you ask for x86 build yesterday. Here is the result:
> > Total: Before=306735842, After=312600260, chg +1.91%
> >
> > In my case of a mobile phone, the difference is about 2MiB on 14MiB kernel image
> > (not compressed).
> > The reduced size is often critical sometimes, especially for low-end phones, say
> > a system with 512MB DDR memory.
> >
> > Another smaller arm system in my hand, kernel size reduced about
> > 600KiB to the zImage
> > of 4.2MiB.
>
> The numbers support the assumption that "memory consumption is increasing
> too much" sentence is not fully accurate.
OK, I may change the description more accurate. I was thinking about
only embedded
environment for this patch. But it really should be accurate for all
kinds users to learn
about it.
.
> According to the result of
> compilation for mobile phone, it looks like the problem with explode of
> prints, which is better to clean, before introducing extra config.
I don't think the debug log print is too much in my kernel. I didn't add extra
debug print other than its original code.
In fact it is very close to one of GKI kernels which could be found at
AOSP kernel/common branch: android-5.4.
>
> >
> > >
> > > I imagine that people who are interested in decreasing memory
> > > footprint will use minimal config anyway, so it is very interesting
> > > to see who is the target audience for this change?
> >
> > My motivation came from the concept of GKI (Generic Kernel Image) in Android.
> > Google will release a common kernel image (binary) to all of the Android system
> > vendors in the world instead of letting them to build their owns as before.
> > Every SoC vendor's device drivers will be provided in kernel modules only.
> > By my patch, the driver owners could debug their modules in field (say
> > production releases)
> > without having to enable dynamic debug for the whole GKI.
>
> Will Google release that binary with CONFIG_DYNAMIC_DEBUG_CORE disabled?
>
In Google's plan, there will be only one GKI (no debug version) for
one Android version per kernel version per year.
So if I request to enable it and they accept my request (actually they
did), the config will be opened in that
GKI release for this year.
> If yes, by introducing you kernel config, these driver authors won't
> be able to enable debug on GKI (at least for production) at all.
> If no, what is the point of this change?
I am sorry to make you feel confused.
One of the main purpose of this change is to export the core
functions of dynamic debug to kernel modules.
These functions are defined in lib/dynamic_debug.c.
EXPORT_SYMBOL(__dynamic_pr_debug);
EXPORT_SYMBOL(__dynamic_dev_dbg);
EXPORT_SYMBOL(__dynamic_netdev_dbg);
EXPORT_SYMBOL(__dynamic_ibdev_dbg);
These are only being built when CONFIG_DYNAMIC_DEBUG is set. But all
pr_debug in GKI will be built-in as well.
It will increase not very much size as you pointed out but might worth
to be considerred for some cases.
To eliminate this "side-effect", my change will give an option to
people like Google guys to export these symbols
without the burden of size it adds before.
-Orson
>
> >
> > -Orson
> >
> > >
> > > Thanks
> > >
> > > >
> > > > Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
> > > > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > ---
> > > > Changes to V2:
> > > > 1) Change DEBUG_MODULE to DYNAMIC_DEBUG_MODULE.
> > > > 2) Change more #if defined(DYNAMIC_DEBUG) condition (in net.h, netdevice.h
> > > > and ib_verbs.h).
> > > > 3) Rewrite description in howto document.
> > > > 4) Add acked-by from Greg.
> > > >
> > > >
> > > > Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++
> > > > include/linux/dev_printk.h | 6 ++++--
> > > > include/linux/dynamic_debug.h | 2 +-
> > > > include/linux/net.h | 3 ++-
> > > > include/linux/netdevice.h | 6 ++++--
> > > > include/linux/printk.h | 14 +++++++++-----
> > > > include/rdma/ib_verbs.h | 6 ++++--
> > > > lib/Kconfig.debug | 12 ++++++++++++
> > > > lib/Makefile | 2 +-
> > > > lib/dynamic_debug.c | 9 +++++++--
> > > > 10 files changed, 49 insertions(+), 16 deletions(-)
> > > >
> > > > diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
> > > > index 0dc2eb8..1012bd9 100644
> > > > --- a/Documentation/admin-guide/dynamic-debug-howto.rst
> > > > +++ b/Documentation/admin-guide/dynamic-debug-howto.rst
> > > > @@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if
> > > > ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
> > > > enabled per-callsite.
> > > >
> > > > +If you do not want to enable dynamic debug globally (i.e. in some embedded
> > > > +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic
> > > > +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any
> > > > +modules which you'd like to dynamically debug later.
> > > > +
> > > > If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
> > > > shortcut for ``print_hex_dump(KERN_DEBUG)``.
> > > >
> > > > diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
> > > > index 5aad06b..3028b64 100644
> > > > --- a/include/linux/dev_printk.h
> > > > +++ b/include/linux/dev_printk.h
> > > > @@ -109,7 +109,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...)
> > > > #define dev_info(dev, fmt, ...) \
> > > > _dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define dev_dbg(dev, fmt, ...) \
> > > > dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
> > > > #elif defined(DEBUG)
> > > > @@ -181,7 +182,8 @@ do { \
> > > > dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
> > > > #define dev_info_ratelimited(dev, fmt, ...) \
> > > > dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > > #define dev_dbg_ratelimited(dev, fmt, ...) \
> > > > do { \
> > > > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> > > > index 4cf02ec..abcd5fd 100644
> > > > --- a/include/linux/dynamic_debug.h
> > > > +++ b/include/linux/dynamic_debug.h
> > > > @@ -48,7 +48,7 @@ struct _ddebug {
> > > >
> > > >
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
> > > > int ddebug_add_module(struct _ddebug *tab, unsigned int n,
> > > > const char *modname);
> > > > extern int ddebug_remove_module(const char *mod_name);
> > > > diff --git a/include/linux/net.h b/include/linux/net.h
> > > > index 6451425..7b7b21a 100644
> > > > --- a/include/linux/net.h
> > > > +++ b/include/linux/net.h
> > > > @@ -264,7 +264,8 @@ do { \
> > > > net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
> > > > #define net_info_ratelimited(fmt, ...) \
> > > > net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define net_dbg_ratelimited(fmt, ...) \
> > > > do { \
> > > > DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
> > > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > > > index 130a668..e874643 100644
> > > > --- a/include/linux/netdevice.h
> > > > +++ b/include/linux/netdevice.h
> > > > @@ -4868,7 +4868,8 @@ do { \
> > > > #define MODULE_ALIAS_NETDEV(device) \
> > > > MODULE_ALIAS("netdev-" device)
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define netdev_dbg(__dev, format, args...) \
> > > > do { \
> > > > dynamic_netdev_dbg(__dev, format, ##args); \
> > > > @@ -4938,7 +4939,8 @@ do { \
> > > > #define netif_info(priv, type, dev, fmt, args...) \
> > > > netif_level(info, priv, type, dev, fmt, ##args)
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define netif_dbg(priv, type, netdev, format, args...) \
> > > > do { \
> > > > if (netif_msg_##type(priv)) \
> > > > diff --git a/include/linux/printk.h b/include/linux/printk.h
> > > > index e061635..b64c39c 100644
> > > > --- a/include/linux/printk.h
> > > > +++ b/include/linux/printk.h
> > > > @@ -286,8 +286,9 @@ extern int kptr_restrict;
> > > > /*
> > > > * These can be used to print at the various log levels.
> > > > * All of these will print unconditionally, although note that pr_debug()
> > > > - * and other debug macros are compiled out unless either DEBUG is defined
> > > > - * or CONFIG_DYNAMIC_DEBUG is set.
> > > > + * and other debug macros are compiled out unless either DEBUG is defined,
> > > > + * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
> > > > + * DYNAMIC_DEBUG_MODULE being defined for any modules.
> > > > */
> > > > #define pr_emerg(fmt, ...) \
> > > > printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
> > > > @@ -322,7 +323,8 @@ extern int kptr_restrict;
> > > >
> > > >
> > > > /* If you are writing a driver, please use dev_dbg instead */
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #include <linux/dynamic_debug.h>
> > > >
> > > > /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
> > > > @@ -448,7 +450,8 @@ extern int kptr_restrict;
> > > > #endif
> > > >
> > > > /* If you are writing a driver, please use dev_dbg instead */
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > > #define pr_debug_ratelimited(fmt, ...) \
> > > > do { \
> > > > @@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
> > > >
> > > > #endif
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
> > > > groupsize, buf, len, ascii) \
> > > > dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
> > > > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> > > > index bbc5cfb..e072ef6 100644
> > > > --- a/include/rdma/ib_verbs.h
> > > > +++ b/include/rdma/ib_verbs.h
> > > > @@ -100,7 +100,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...);
> > > > __printf(2, 3) __cold
> > > > void ibdev_info(const struct ib_device *ibdev, const char *format, ...);
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > #define ibdev_dbg(__dev, format, args...) \
> > > > dynamic_ibdev_dbg(__dev, format, ##args)
> > > > #else
> > > > @@ -133,7 +134,8 @@ do { \
> > > > #define ibdev_info_ratelimited(ibdev, fmt, ...) \
> > > > ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__)
> > > >
> > > > -#if defined(CONFIG_DYNAMIC_DEBUG)
> > > > +#if defined(CONFIG_DYNAMIC_DEBUG) || \
> > > > + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
> > > > /* descriptor check is first to prevent flooding with "callbacks suppressed" */
> > > > #define ibdev_dbg_ratelimited(ibdev, fmt, ...) \
> > > > do { \
> > > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > > > index 21d9c5f..9ab791b 100644
> > > > --- a/lib/Kconfig.debug
> > > > +++ b/lib/Kconfig.debug
> > > > @@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
> > > > default n
> > > > depends on PRINTK
> > > > depends on (DEBUG_FS || PROC_FS)
> > > > + select DYNAMIC_DEBUG_CORE
> > > > help
> > > >
> > > > Compiles debug level messages into the kernel, which would not
> > > > @@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
> > > > See Documentation/admin-guide/dynamic-debug-howto.rst for additional
> > > > information.
> > > >
> > > > +config DYNAMIC_DEBUG_CORE
> > > > + bool "Enable core function of dynamic debug support"
> > > > + depends on PRINTK
> > > > + depends on (DEBUG_FS || PROC_FS)
> > > > + help
> > > > + Enable core functional support of dynamic debug. It is useful
> > > > + when you want to tie dynamic debug to your kernel modules with
> > > > + DYNAMIC_DEBUG_MODULE defined for each of them, especially for
> > > > + the case of embedded system where the kernel image size is
> > > > + sensitive for people.
> > > > +
> > > > config SYMBOLIC_ERRNAME
> > > > bool "Support symbolic error names in printf"
> > > > default y if PRINTK
> > > > diff --git a/lib/Makefile b/lib/Makefile
> > > > index 685aee6..8952772 100644
> > > > --- a/lib/Makefile
> > > > +++ b/lib/Makefile
> > > > @@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
> > > >
> > > > obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
> > > >
> > > > -obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
> > > > +obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
> > > > obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
> > > >
> > > > obj-$(CONFIG_NLATTR) += nlattr.o
> > > > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> > > > index 8f199f4..321437b 100644
> > > > --- a/lib/dynamic_debug.c
> > > > +++ b/lib/dynamic_debug.c
> > > > @@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
> > > > int verbose_bytes = 0;
> > > >
> > > > if (&__start___verbose == &__stop___verbose) {
> > > > - pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > > > - return 1;
> > > > + if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
> > > > + pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
> > > > + return 1;
> > > > + }
> > > > + pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
> > > > + ddebug_init_success = 1;
> > > > + return 0;
> > > > }
> > > > iter = __start___verbose;
> > > > modname = iter->modname;
> > > > --
> > > > 2.7.4
> > > >
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-04-22 16:02 ` Orson Zhai
@ 2020-05-15 9:55 ` Petr Mladek
2020-05-16 3:55 ` Orson Zhai
0 siblings, 1 reply; 8+ messages in thread
From: Petr Mladek @ 2020-05-15 9:55 UTC (permalink / raw)
To: Orson Zhai
Cc: Leon Romanovsky, Orson Zhai, Jason Baron, Randy Dunlap,
Linux Kernel Mailing List, linux-doc, netdev, linux-rdma,
Jonathan Corbet, Sergey Senozhatsky, Steven Rostedt,
Greg Kroah-Hartman, David S . Miller, Jakub Kicinski,
Doug Ledford, Jason Gunthorpe, Andrew Morton,
Android Kernel Team, Orson Zhai
On Thu 2020-04-23 00:02:48, Orson Zhai wrote:
> On Wed, Apr 22, 2020 at 10:25 PM Leon Romanovsky <leon@kernel.org> wrote:
> >
> > On Wed, Apr 22, 2020 at 09:06:08PM +0800, Orson Zhai wrote:
> > > On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
> > > My motivation came from the concept of GKI (Generic Kernel Image) in Android.
> > > Google will release a common kernel image (binary) to all of the Android system
> > > vendors in the world instead of letting them to build their owns as before.
> > > Every SoC vendor's device drivers will be provided in kernel modules only.
> > > By my patch, the driver owners could debug their modules in field (say
> > > production releases)
> > > without having to enable dynamic debug for the whole GKI.
> >
> > Will Google release that binary with CONFIG_DYNAMIC_DEBUG_CORE disabled?
> >
> In Google's plan, there will be only one GKI (no debug version) for
> one Android version per kernel version per year.
Are there plans to use modules with debug messages enabled on production
systems?
IMHO, the debug messages are primary needed during development and
when fixing bugs. I am sure that developers will want to enable many
more features that will help with debugging and which will be disabled
on production systems.
I expect that Google will not release only the single binary. They
should release also the sources and build configuration. Then
developers might build their own versions with the needed debugging
features enabled.
Best Regards,
Petr
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-05-15 9:55 ` Petr Mladek
@ 2020-05-16 3:55 ` Orson Zhai
2020-05-18 9:50 ` Petr Mladek
0 siblings, 1 reply; 8+ messages in thread
From: Orson Zhai @ 2020-05-16 3:55 UTC (permalink / raw)
To: Petr Mladek
Cc: Leon Romanovsky, Orson Zhai, Jason Baron, Randy Dunlap,
Linux Kernel Mailing List, linux-doc, netdev, linux-rdma,
Jonathan Corbet, Sergey Senozhatsky, Steven Rostedt,
Greg Kroah-Hartman, David S . Miller, Jakub Kicinski,
Doug Ledford, Jason Gunthorpe, Andrew Morton,
Android Kernel Team, Orson Zhai
On Fri, May 15, 2020 at 5:55 PM Petr Mladek <pmladek@suse.com> wrote:
>
> On Thu 2020-04-23 00:02:48, Orson Zhai wrote:
> > On Wed, Apr 22, 2020 at 10:25 PM Leon Romanovsky <leon@kernel.org> wrote:
> > >
> > > On Wed, Apr 22, 2020 at 09:06:08PM +0800, Orson Zhai wrote:
> > > > On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
> > > > My motivation came from the concept of GKI (Generic Kernel Image) in Android.
> > > > Google will release a common kernel image (binary) to all of the Android system
> > > > vendors in the world instead of letting them to build their owns as before.
> > > > Every SoC vendor's device drivers will be provided in kernel modules only.
> > > > By my patch, the driver owners could debug their modules in field (say
> > > > production releases)
> > > > without having to enable dynamic debug for the whole GKI.
> > >
> > > Will Google release that binary with CONFIG_DYNAMIC_DEBUG_CORE disabled?
> > >
> > In Google's plan, there will be only one GKI (no debug version) for
> > one Android version per kernel version per year.
>
> Are there plans to use modules with debug messages enabled on production
> systems?
Yes, but in a managed way. They are not being enabled directly to log buffer.
Users / FAEs (Field Application Engineer) might control to open or
close every single one on-the-fly.
>
> IMHO, the debug messages are primary needed during development and
> when fixing bugs. I am sure that developers will want to enable many
> more features that will help with debugging and which will be disabled
> on production systems.
I agree with you in general speaking.
For real production build we usually keep a few critical debugging
methods in case of some
potential bugs which are extremely hard to be found in production test.
Dynamic debug is one of these methods.
I assume it is widely used for maintenance to PC or server because I
can find it is enabled in some
popular Linux distribution configs.
Here is the search result from my PC with Ubuntu default installation.
zhai@ThinkPad:/boot$ cat config-4.15.0-99-generic | grep DYNAMIC_DEBUG
CONFIG_DYNAMIC_DEBUG=y
>
> I expect that Google will not release only the single binary. They
> should release also the sources and build configuration. Then
Yes, they have released the source and configuration which could be freely
downloaded from Google's website.
> developers might build their own versions with the needed debugging
> features enabled.
Yes, we do have the debug build for this.
But as I mentioned above, it is a little bit different for my requirement.
Actually my patch is to address the problem for embedded system where
image size is needed to be
considered when CONFIG_DYNAMIC_DEBUG is being enable globally.
For a "make allyesconfig" build, 2,335,704 bytes will be increased by
enabling CONFIG_DYNAMIC_DEBUG.
It is trivial for PC or server but might matter for embedded product.
So my patch is to give user an option to
only enable dynamic debug for modules especially in this GKI case.
Thanks
Orson
>
> Best Regards,
> Petr
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only
2020-05-16 3:55 ` Orson Zhai
@ 2020-05-18 9:50 ` Petr Mladek
0 siblings, 0 replies; 8+ messages in thread
From: Petr Mladek @ 2020-05-18 9:50 UTC (permalink / raw)
To: Orson Zhai
Cc: Leon Romanovsky, Orson Zhai, Jason Baron, Randy Dunlap,
Linux Kernel Mailing List, linux-doc, netdev, linux-rdma,
Jonathan Corbet, Sergey Senozhatsky, Steven Rostedt,
Greg Kroah-Hartman, David S . Miller, Jakub Kicinski,
Doug Ledford, Jason Gunthorpe, Andrew Morton,
Android Kernel Team, Orson Zhai
On Sat 2020-05-16 11:55:04, Orson Zhai wrote:
> On Fri, May 15, 2020 at 5:55 PM Petr Mladek <pmladek@suse.com> wrote:
> >
> > On Thu 2020-04-23 00:02:48, Orson Zhai wrote:
> > > On Wed, Apr 22, 2020 at 10:25 PM Leon Romanovsky <leon@kernel.org> wrote:
> > > >
> > > > On Wed, Apr 22, 2020 at 09:06:08PM +0800, Orson Zhai wrote:
> > > > > On Tue, Apr 21, 2020 at 3:10 AM Leon Romanovsky <leon@kernel.org> wrote:
> > > > > My motivation came from the concept of GKI (Generic Kernel Image) in Android.
> > > > > Google will release a common kernel image (binary) to all of the Android system
> > > > > vendors in the world instead of letting them to build their owns as before.
> > > > > Every SoC vendor's device drivers will be provided in kernel modules only.
> > > > > By my patch, the driver owners could debug their modules in field (say
> > > > > production releases)
> > > > > without having to enable dynamic debug for the whole GKI.
> > > >
> > > > Will Google release that binary with CONFIG_DYNAMIC_DEBUG_CORE disabled?
> > > >
> > > In Google's plan, there will be only one GKI (no debug version) for
> > > one Android version per kernel version per year.
> >
> > Are there plans to use modules with debug messages enabled on production
> > systems?
>
> Yes, but in a managed way. They are not being enabled directly to log buffer.
> Users / FAEs (Field Application Engineer) might control to open or
> close every single one on-the-fly.
I see.
> > IMHO, the debug messages are primary needed during development and
> > when fixing bugs. I am sure that developers will want to enable many
> > more features that will help with debugging and which will be disabled
> > on production systems.
>
> I agree with you in general speaking.
> For real production build we usually keep a few critical debugging
> methods in case of some
> potential bugs which are extremely hard to be found in production test.
> Dynamic debug is one of these methods.
> I assume it is widely used for maintenance to PC or server because I
> can find it is enabled in some
> popular Linux distribution configs.
Fair enough.
Feel free to add:
Acked-by: Petr Mladek <pmladek@suse.com>
Best Regards,
Petr
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-05-18 9:50 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-20 18:43 [PATCH V2] dynamic_debug: Add an option to enable dynamic debug for modules only Orson Zhai
2020-04-20 19:10 ` Leon Romanovsky
2020-04-22 13:06 ` Orson Zhai
2020-04-22 14:25 ` Leon Romanovsky
2020-04-22 16:02 ` Orson Zhai
2020-05-15 9:55 ` Petr Mladek
2020-05-16 3:55 ` Orson Zhai
2020-05-18 9:50 ` Petr Mladek
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).