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Commit 832a7710 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
Browse files

s390/debug: avoid function call for debug_sprintf_* 



debug_sprintf_event/exception are called even for debug events
with a disabling debug level. All other functions already do
the check in a wrapper function. Lets do the same here.
Due to the var_args the compiler rejects to make this function
inline. So let's wrap this via a macro.
This patch saves around 80 ns on my z196 for a KVM round trip (we
have two debug statements for entry and exit) when KVM is build as
a module.
The savings for built-in drivers is smaller as we then avoid the
PLT overhead for a function call.

Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent ed7d56e1

arch/s390/include/asm/debug.h

+27 −2
Original line number Diff line number Diff line
@@ -151,9 +151,21 @@ debug_text_event(debug_info_t* id, int level, const char* txt) 
 * stored in the s390dbf. See Documentation/s390/s390dbf.txt for more details!

 */

extern debug_entry_t *

debug_sprintf_event(debug_info_t* id,int level,char *string,...)

__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)

	__attribute__ ((format(printf, 3, 4)));



#define debug_sprintf_event(_id, _level, _fmt, ...)			\

({									\

	debug_entry_t *__ret;						\

	debug_info_t *__id = _id;					\

	int __level = _level;						\

	if ((!__id) || (__level > __id->level))				\

		__ret = NULL;						\

	else								\

		__ret = __debug_sprintf_event(__id, __level,		\

					      _fmt, ## __VA_ARGS__);	\

	__ret;								\

})



static inline debug_entry_t*

debug_exception(debug_info_t* id, int level, void* data, int length)
@@ -194,9 +206,22 @@ debug_text_exception(debug_info_t* id, int level, const char* txt) 
 * stored in the s390dbf. See Documentation/s390/s390dbf.txt for more details!

 */

extern debug_entry_t *

debug_sprintf_exception(debug_info_t* id,int level,char *string,...)

__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)

	__attribute__ ((format(printf, 3, 4)));



#define debug_sprintf_exception(_id, _level, _fmt, ...)			\

({									\

	debug_entry_t *__ret;						\

	debug_info_t *__id = _id;					\

	int __level = _level;						\

	if ((!__id) || (__level > __id->level))				\

		__ret = NULL;						\

	else								\

		__ret = __debug_sprintf_exception(__id, __level,	\

						  _fmt, ## __VA_ARGS__);\

	__ret;								\

})



int debug_register_view(debug_info_t* id, struct debug_view* view);

int debug_unregister_view(debug_info_t* id, struct debug_view* view);

arch/s390/kernel/debug.c

+4 −8
Original line number Diff line number Diff line
@@ -1019,7 +1019,7 @@ debug_count_numargs(char *string) 
 */



debug_entry_t*

debug_sprintf_event(debug_info_t* id, int level,char *string,...)

__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)

{

	va_list   ap;

	int numargs,idx;
@@ -1027,8 +1027,6 @@ debug_sprintf_event(debug_info_t* id, int level,char *string,...) 
	debug_sprintf_entry_t *curr_event;

	debug_entry_t *active;



	if((!id) || (level > id->level))

		return NULL;

	if (!debug_active || !id->areas)

		return NULL;

	numargs=debug_count_numargs(string);
@@ -1050,14 +1048,14 @@ debug_sprintf_event(debug_info_t* id, int level,char *string,...) 


	return active;

}

EXPORT_SYMBOL(debug_sprintf_event);

EXPORT_SYMBOL(__debug_sprintf_event);



/*

 * debug_sprintf_exception:

 */



debug_entry_t*

debug_sprintf_exception(debug_info_t* id, int level,char *string,...)

__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)

{

	va_list   ap;

	int numargs,idx;
@@ -1065,8 +1063,6 @@ debug_sprintf_exception(debug_info_t* id, int level,char *string,...) 
	debug_sprintf_entry_t *curr_event;

	debug_entry_t *active;



	if((!id) || (level > id->level))

		return NULL;

	if (!debug_active || !id->areas)

		return NULL;
@@ -1089,7 +1085,7 @@ debug_sprintf_exception(debug_info_t* id, int level,char *string,...) 


	return active;

}

EXPORT_SYMBOL(debug_sprintf_exception);

EXPORT_SYMBOL(__debug_sprintf_exception);



/*

 * debug_register_view: