mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-25 08:50:53 +07:00
d430d3d7e6
Introduce:
static __always_inline bool static_branch(struct jump_label_key *key);
instead of the old JUMP_LABEL(key, label) macro.
In this way, jump labels become really easy to use:
Define:
struct jump_label_key jump_key;
Can be used as:
if (static_branch(&jump_key))
do unlikely code
enable/disale via:
jump_label_inc(&jump_key);
jump_label_dec(&jump_key);
that's it!
For the jump labels disabled case, the static_branch() becomes an
atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(),
atomic_dec() operations. We show testing results for this change below.
Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct.
Since we now require a 'struct jump_label_key *key', we can store a pointer into
the jump table addresses. In this way, we can enable/disable jump labels, in
basically constant time. This change allows us to completely remove the previous
hashtable scheme. Thanks to Peter Zijlstra for this re-write.
Testing:
I ran a series of 'tbench 20' runs 5 times (with reboots) for 3
configurations, where tracepoints were disabled.
jump label configured in
avg: 815.6
jump label *not* configured in (using atomic reads)
avg: 800.1
jump label *not* configured in (regular reads)
avg: 803.4
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110316212947.GA8792@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Suggested-by: H. Peter Anvin <hpa@linux.intel.com>
Tested-by: David Daney <ddaney@caviumnetworks.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
85 lines
2.6 KiB
C
85 lines
2.6 KiB
C
#ifndef _DYNAMIC_DEBUG_H
|
|
#define _DYNAMIC_DEBUG_H
|
|
|
|
/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
|
|
* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
|
|
* use independent hash functions, to reduce the chance of false positives.
|
|
*/
|
|
extern long long dynamic_debug_enabled;
|
|
extern long long dynamic_debug_enabled2;
|
|
|
|
/*
|
|
* An instance of this structure is created in a special
|
|
* ELF section at every dynamic debug callsite. At runtime,
|
|
* the special section is treated as an array of these.
|
|
*/
|
|
struct _ddebug {
|
|
/*
|
|
* These fields are used to drive the user interface
|
|
* for selecting and displaying debug callsites.
|
|
*/
|
|
const char *modname;
|
|
const char *function;
|
|
const char *filename;
|
|
const char *format;
|
|
unsigned int lineno:24;
|
|
/*
|
|
* The flags field controls the behaviour at the callsite.
|
|
* The bits here are changed dynamically when the user
|
|
* writes commands to <debugfs>/dynamic_debug/control
|
|
*/
|
|
#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
|
|
#define _DPRINTK_FLAGS_INCL_MODNAME (1<<1)
|
|
#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
|
|
#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
|
|
#define _DPRINTK_FLAGS_INCL_TID (1<<4)
|
|
#define _DPRINTK_FLAGS_DEFAULT 0
|
|
unsigned int flags:8;
|
|
char enabled;
|
|
} __attribute__((aligned(8)));
|
|
|
|
|
|
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
|
|
const char *modname);
|
|
|
|
#if defined(CONFIG_DYNAMIC_DEBUG)
|
|
extern int ddebug_remove_module(const char *mod_name);
|
|
extern int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
|
|
__attribute__ ((format (printf, 2, 3)));
|
|
|
|
#define dynamic_pr_debug(fmt, ...) do { \
|
|
static struct _ddebug descriptor \
|
|
__used \
|
|
__attribute__((section("__verbose"), aligned(8))) = \
|
|
{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
|
|
_DPRINTK_FLAGS_DEFAULT }; \
|
|
if (unlikely(descriptor.enabled)) \
|
|
__dynamic_pr_debug(&descriptor, pr_fmt(fmt), ##__VA_ARGS__); \
|
|
} while (0)
|
|
|
|
|
|
#define dynamic_dev_dbg(dev, fmt, ...) do { \
|
|
static struct _ddebug descriptor \
|
|
__used \
|
|
__attribute__((section("__verbose"), aligned(8))) = \
|
|
{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
|
|
_DPRINTK_FLAGS_DEFAULT }; \
|
|
if (unlikely(descriptor.enabled)) \
|
|
dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); \
|
|
} while (0)
|
|
|
|
#else
|
|
|
|
static inline int ddebug_remove_module(const char *mod)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#define dynamic_pr_debug(fmt, ...) \
|
|
do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
|
|
#define dynamic_dev_dbg(dev, fmt, ...) \
|
|
do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0)
|
|
#endif
|
|
|
|
#endif
|